THE
INCIDENCE
OF
CONGENITAL
MALFORMATIONS:
A
STUDY
OF
5,964 PREGNANCIESBy RUSTIN MCINTOSH, M.D.,* KATHARINE K. MERRITT, M.D.,
Muiy R. RICHARDS, M.D., Mmi H. SAMUELS, M.D.,
AND MARJORIE T. BELLOWS, M.S.f
New York City
505
PART I
T
HIS report presents material on theincidence of congenital malformations
among the products of gestation of 5,964
women admitted to the ante partum clinic
of the Sloane Hospital for Women over a
period of five years. It is part of a study
undertaken by members of the Departments
of Obstetrics and Pediatrics, College of
Phy-sicians and Surgeons, Columbia University
to determine the relation of infections and
other illnesses occurring during pregnancy,
to the incidence of abortions, stillbirths,
prematurity, infant deaths and congenital
malformations.
The study was begun in the Sloane ante
partum clinic in October, 1946, and the last
infants admitted were examined at one year
of age about March 11, 1953.
PLAN OF STUDY
All expectant mothers admitted to the
Sloane ante partum clinic with a duration of
pregnancy of four months or less on their
first visit were included in the
investiga-tion.
Of the 6,381 women admitted to the
study, 417 were excluded prior to delivery
for the following reasons: departure from
New York City prior to delivery; transfer to
From the Departments of Pediatrics, and of
Obstetrics and Gynecology, Columbia University
College of Physicians and Surgeons, Babies
Hos-pital, and Sloane Hospital for Women.
This investigation was aided by grants from the
Rockefeller Foundation, the Life Insurance Medical
Research Fund, the Snyder Ophthalmic Fund, the
New York State Department of Health and the
Association for the Aid of Crippled Children.
(Received for publication July 9, 1954.)
Address: 622 W. 168th Street, New York 32,
N.Y.
f
Statistician, American Heart Association.private care; discharge from clinic because
of habitual failure to keep appointments, or
discharge from clinic because it was found
that they were not pregnant. Women who
had ectopic pregnancies and therapeutic
abortions were also excluded. There remain
5,964 pregnancies included in this analysis.
Type of Patients Admitted to the Ante
Pm-turn Clinic
The clinic accepts the vast majority of all
patients who apply for admission. In the
rare instance when selection is necessary
because of a full clinic quota for a particular
month, preference is given to those women
who have had previous ante partum care
in the institution, or to those patients who
are of special obstetrical or medical
inter-est.
In assessing the economic status of the
group studied, it was found that
approxi-mately half of the patients paid the
estab-lished clinic rate for their care during
preg-nancy, for delivery and for a follow-up visit.
A considerable proportion of these carried
medical insurance. The remainder either
were admitted free, made a partial
pay-ment, or had their expenses paid in part by
the New York City Department of
Web-fare. There was no distinction made with
regard to race, creed or color, and payment
status was the same for both white and
non-white women.
Plan of Procedure
The pregnant woman’s initial history was
taken by one of the physicians on the study
team, and the mother was closely
ques-tioned about the illnesses which she had
had since her last menstrual period. A
in-fectious amid contagious ilimiesses in the
pa-tient or her family and specific questions
were asked about symptoms of measles,
rubella, chickenpox, mumps, poliomyelitis,
Or infectious hepatitis. The patient was
asked if she had been to a doctor or whether
a doctor had been to hen home since her
pregnancy began, and for what reason. On
each subsequemit visit to the ante partum
clinic, any important events in the woman’s
pregnancy between her previous visit and
the current one were noted by specially
trained non-medical members of the study
group.
The regular schedule for visits to the ante
partum clinic required one visit a month to
the eighth month, two during the eighth
momlth and one per week in the ninth
month.
The working questionnaire used on the
first and subsequent visits to determine
whether there had been any illness during
pregnancy is shown below:
If the mother arrived at the ante partum
clinic on her second or a simbsequent visit
with complaint of an acute illness or rash,
her condition was usually checked by a
doctor on the team. If she telephoned that
she on a member of the family was ill, and
a contagious disease was suspected, a
visit-ing nurse was sent to her home, or an effort
was made to find out from the attending
physician the nature of her illness. The
per-tinent data accumulated on the working
sheets were subsequently summarized
to-gether with information from the patient’s
obstretrical summary after delivery had
taken place.
The infant was given a careful physical
examination in the neonatal period by a
pediatrician on the study team, with
par-ticular attention to the detection of
congeni-tal malformations. The birth weight, length
and head and chest circumference were
re-corded. Roentgenograms of the head
(lat-eral) and of the chest (antero-posterior)
Unit No Date of last clinic visit Date of present visit
Name Date of next appt
1. Have you had any illness since (this pregnancy began) (the last time you were here) No
Describe Dates
Fever Bed
2. have you been to a doctor since (this pregnancy began) (the last time you were here) No
For what Dates
Name and address of M.D
3. Have you had any colds, sore throats, cough, sinus involvement: No
I)escribe Dates
4. Have you had any rash or skin trouble: No Dates
J)escribe
5. Have you had a) cold sores : No I)ate d) abscessed teeth :No Date
b) boils : No Date e) swollen glands :No Date
c) earache : No Date f) eye inflammation :No Date
6. Have you had nausea, vomiting or diarrhea: No Dates
Describe
7. Have you had any signs of jaundice: No Date
8. Have any members of your family been ill: No
Date Relation Describe
Date Relation Describe
Date Relation Describe
9. Have you had any injections or vaccinations: No Date For
‘FABLE I
OuTcoME OF
Total De!,i’eries
\‘umber Per cent
were made, and arm examination of the eyes
(
external amid funduscopic) was carried outby an ophthalmologist. Additional RG or
ophthalmological examinations were made
when any abnormality was suspected. Six
and twelve-month follow-up examinations
of the infants were made in special clinics
organized for the purpose. Members of the
Department of Dentistry attended the
spe-cial follow-up clinics regularly to examine
the teeth of the infants. When abnormalities
were present or suspected the patients were
referred to other clinics of the Medical
Cen-ter, especially those of the Departments of
Neurology, Ophthalmology, Orthopedics,
Otolaryngoiogy, Urology and the Pediatric
Cardiac Clinic.
A great effort was made to have an
ex-amination made of the “lost” products of
conception. Fetuses approximately 10 cm.
or less in length ( those on which it was felt
that a regular autopsy could not be done)
were sent to the Department of
Embryol-ogy, Carnegie Institution of Washington,
Baltimore, Maryland, for examination.
Larger fetuses and practically all stillborn
infants, and infants who died in the
neo-natal period, were subjected to postmortem
study in the Pathological Laboratory of the
Babies Hospital (Presbyterian Hospital). A
modified examination was made of fetuses
which had a gestational age of
approxi-mately 16 to 20 weeks (length
approxi-mately 10 cm. to 16 cm., and weight
ap-proximately 100 gm. to 300 gm.). The
era-nial vault and its contents were inspected,
also the neck, the thorax and the abdomen,
and the presence or the absence of the
van-ous organs, their location and their size were
noted. If the organs appeared to be
ex-ternally normal no fine dissection was done,
except of the heart, the ascending aorta,
and the pulmonary artery. A dissecting
microscope was used for the cardiovascular
system when necessary. No microscopic
see-tions were made of small fetuses. Fetuses
a These pathological examinations were made
through the cooperation of Drs. George W. Corner,
C. H. Heuser, and Elizabeth NI. Ramsey.
Abortions 304 5.0
Stillbirths I I I I.S
Neonatal deaths* 105 1 .5
Live birthst 5530 91 .4
‘Total (leliveries (11)53 1 00 .0
* The terni “neonatal (leaths is used for infants
who died within a month of l)irth.
t Live births excludes neonatal deaths.
of the larger weight group, stillborn
in-fants, and infants who died in the neonatal
period had the usual routine autopsy
pro-cedure, including microscopic sections.
When permitted, microscopic examimiation
of the eyes was made by a member of the
staff of the Institute of Ophthalmology.
A total of 5,964 pregnancies which
re-suited in 6,053 products of conception were
studied. There were 5,878 single births, 166
twins, and 9 triplets. The outcome of these
pregnancies is shown in Table I.
Table II shows the number and
propor-tion of autopsies performed on abortions,
stillbirths, and infants who died in the
neo-natal period.
The autopsy rate on the abortions is low
because in 29.3% of the cases, abortion
oc-curred outside of the hospital, and in an
additional 34.2%, although the women were
hospitalized, the fetus was not recovered.
The study team did not get an opportunity
to examine the stillborn infants, although a
TABLE II
NUMBER AND PER CENT OF AUTOPSIES PERFORMED
Total
Autopsies
-?sTnmber
Performed
Per cent
Abortions 304 1 1 1 36.5
Stillbirths 1 1 1 96 86.5
.Ige of .tlother
Total White Non-white
Percentage Distribution by Aye
Total t’L’hite Non-white
Urmder20years 289 174 115 4.8 .5.1 4.3
20-24 1629 878 751 26.9 .l6.() ‘28.1
25-29 1845 968 877 30.5 ‘28.6 3L8
30-34 1357 788 569 22.4 23.3 21.3
35-3t) 747 450 297 12.3 13.3 11.1
40 years 1111(1 over 186 121 6.5 3.1 3.6 2.4
Total 6053 3379 2674 100.0 100.0 100.0
Order of Birth
Number of Deliveries
Total White Non-White
1 2146 1156 990 35.5 34.2 37.0
2 1864 985 879 30.8 29.2 32.9
3 1059 617 442 17.5 18.3 16.5
4andhigher 984 621 363 16.3 18.4 13.6
total 6053 3379 2674 100.0 100.0 100.0
‘FABLE III
NUMBER ANI) 1EIWENTAGE I)msTumBuTIoN OF l)ELmvEmuEs BY Coioi AND AGE OF MOTHER
.\‘umber of Deliveries
gross description was available from the
delivery room record. It did not examine
personally all the infants born alive,
be-cause some did not survive long enough to
be transferred from the delivery room to the
nursery, or died very soon after their
ar-rival there. In these instances, data were
obtained from notes written by members
of the Obstetric or Pediatric house staffs.
Atmtopsies were performed, however, on
over 85% of both stillbirths and neonatal
deaths.
The study team was successful in
observ-imig 92.4% of the 5,517 infants who were still
living at six months. For 159 infants (2.9%)
not examined by the study team at this later
age, information was obtained by special
request from the family physician or from
other clinics at six or 12 months of age, or
at both ages. Thus there were only 262
infants (4.7%) upon whom no follow-up
cx-amination was made by the study team or
reported on by a private or clinic physician.
The racial distribution of the mothers
merits special comment. The 6,053
dcliv-cries included 3,379 (55.8%) white mothers
and 2,674 (44.2%) non-white. A large part of
the population is Puerto Rican amid the color
distinction was based on the mother’s
state-ment as to race. It is probable that time
nomi-white group is more homogeneous racially
than is the white, since most Puerto Ricans
claim white parentage regardless of
pig-ment considerations.
As shown by Tables III and IV, the
white and non-white groups were
distnib-uted very similarly with respect to both age
and parity. The white women were slightly
older as a group than the non-white and a
slightly larger number were in later
preg-TABLE IV
NUMBER ANI) PERCENTAGE DISTRIBUTION OF DELIVERIES BY CoLOR
OF MOTHER AND ORDER OF BIRTH
Percentage Distribution by Order of Birth
* Excludes neonatal deaths.
TABLE V
NUMBER AND PER CENT OF INFANTS \VITH CONGENITAL
MALFORMATIONS AMONG THOSE WEIGHING MORE
THAN 500 GRAMS AT BIRTH, BY
OUTCOME OF DELIVERY
With Congenital Total Malformations Deliveries --_________
Number Per cent
Antepartum deaths 81 1 1 13.6
Iritrapartum deaths 30 7 23.3
Neonatal deaths 98 29 29.6
Live births* 553() 386 7.0
Total 5739 483 7.5
* Live births excludes neonatal (leatls.
nancies. Both groups of women had the
same amount and quality of prenatal care,
as far as clinic attention and advice were
concerned. To the study team who saw
mothers and infants in clinics, the white and
non-white groups appeared, superficially, to
be comparable as to economic and
educa-tional status. In other words it would
ap-pear that environmental differences which
affect comparison of most white and
non-white groups are not strongly evident in this
particular population.
PART II
iNCIDENCE OF CONGENITAL MALFORMATIONS
Of the 5,739 deliveries in which the fetus
weighed over 500 grams, 433 products of
conception, or 7.5% were found to have
con-genital malformations. (Throughout the
fol-lowing analysis, the 314 abortions in which
the fetus weighed 500 gms. or less are
excluded because of the unreliability of
in-formation regarding the presence or
ab-sence of congenital defects.) Table V shows
the proportion of infants with defects among
stillbirths, neonatal deaths (infants dying
under 1 mo. of age) and among live births0
surviving the neonatal period. The
percent-age of infants with malformations increased
0 Wherever the termii “live-born” is used, it refers
to live born exclusive of deaths under one month.
progressively from 13.6% among fetuses
still-born before delivery, through 23.3% among
stillborn infants at delivery, to 29.6% among
infants who died within 30 days after birth.
In the last group, the frequency of
mal-formations was over four times as high as
among infants who survived the neonatal
period (7.0%). The differences among
ant-partum, intrapartum and neonatal rates may
indicate that many malformations which are
compatible with intrauterine life impose a
fatal hazard at parturition, while others are
incompatible with extrauterine life.
Incidence By Sex and Color Among Live
Born Infants (Table VI)
The proportion of live born male infant
with congenital defects (8.4) was more than
half again as high as among females (5.5)
and the greater male incidence was
ob-served in both white and non-white infants.
Non-white infants with 7.8% showing
de-fects had a rate significantly higher than the
figure for whites (6.3%), and the difference
was observed among both males and
fe-males. The rates for the four sex and color
groups ranged from 9.7% with anomalies
among non-white males to 5.2% among white
females.
TABLE VI
NUMBER AND PER CENT OF LIVEBORN* INFANTS WITh
CONGENITAL MALFORMATIONS BY SEX AND (‘OLOII
Total
Jvith Congenital Malformations
Number Per cent
Males 2793 235 8.4
White 1571 116 7.4
Non-white 1222 119 9.7
Females 2737 151 5.5
White 1530 80 5.2
Non-white 1207 71 .5.9
Total white 3101 196 6.3
Total non-white 2429 190 7.5
Tot (11
JJ’ith Congenital .1! a/formations
Number Per cent
Total
Jh’itlt Congenital Jlalfornmations
Number Per cent
Males 224 17 7.5 2569 218 8.4
\\‘hite 106 8 7.5 1465 108 7.4
Non-white 115 9 7.6 1104 110 10.0
Feitiales 239 28 1 1.7 2495 123 4.9
White 106 13 12.3 1424 67 4.7
Non-white 133 15 11 .3 1074 56 5.2
‘l’otalwhite 212 21 9.9 2889 175 6.1
lotal ImOII-White ‘251 24 9.6 ‘2178 166 7.6
‘rtmI 463 45 9.7 5067 341 6.7
TABLE VII
NUMBER AND PER CENT OF LIvEBouN* INFANTS \VITH CONGENITAL MALFORMATIONS
BY \VEIGIIT AT I)ELmvEIY, SEX AND COLOR
2#{246}0()Grams and hinder Over 2500 Grams
* Excludes imeommatal deaths.
Incidence By Weight Groups Among
Live-born Infants (Table VII)
Live born infants weighing 2500 grams or
less at birth had a significantly higher
pro-portion with defects (9.7%) than did those
weighing over 2500 grams (6.7%). The
differ-ence was most marked among females in
whom the rate for the lower weight group
was 11.7% as compared with 4.9% in the
higher weight group. A comparable
differ-ence ill the frequency of congenital
anoma-lies according to birth weight was observed
among both white and non-white females.
Among males none of the differences
ob-served between weight groups for either
wiiite, non-white or the total group were
significant. Females of the lower weight
group have a somewhat higher risk of
con-genital defects than do males; but females
iii the higher weight group have a lower
risk than do higher weight males.
Incidence According to Maternal Age,
Order of Birth and Color Among Live-born
Infants (Table VIII)
The age of the mother was not shown to
have an effect on the incidemi#{231}e of
mal-formed infants. This confirms the findings
of Carter1 and Worcester et al.2 Birth order
among white women did appear to be
re-lated to incidence, the proportion with
con-genital malformations among third and
higher order births (8.2%) being significantly
higher than for lower order births (5.3%).
Among non-white mothers there were no
significant differences by age or birth order.
PART III
Typi.s OF MALFORMATION
The problem of classification of
congeni-tal malformations presents certain
difficul-ties, as other investigators17 in this field
have found. Since none of the systems of
classification used by the investigators just
listed seems fully satisfactory, and since it
is impracticable to fit all the malformations
encountered into the list of Congenital
Mal-formations included in the Manual of the
International Statistical Classification of
Diseases, Injuries and Causes of Death,8 the
following classification has been adopted
which utilizes a maximum of the
informa-tion available and permits several types
Age of Mother and
Total JJ’hite Non-white
With Congenital With Congenital With (‘ongenital Order of Birth
Total Malformations Total Malformations Total Malformations
Number Per cent Number Per cent Number Per cent
Under 30 years
1st & 2nd births ‘3rd & higher
30 years & over
1st & 2nd births
3rd & higher
233 6.7
179 6.5
54 7.7 3469
2765
704
2061 933
I 128
1888 111 5.9 1581 122 7.7
1512 80 5.3 1253 99 7.9
376 31 8.2 328 23 7.0
3698 241 6.5 1990 105 5.3 1708 136 8.0
1832 145 7.9 1111 9!
5530 386 7.0 3101 196
8.2 721 54 7.5
6.3 2129 190 7.8
1st & 2nd births
(all ages)
3rd &higher
(all ages)
I’otal
TABLE VIII
NUMBER AND PER CENT OF LmvEBouN* INFANTS WITh CONGENITAL MALFORMATIONS
BY AGE OF MOTHER, OISDEu OF BmrTmI AND Coiom
153 7.4 1213 85 7.0 848 68 5.0
62 6.6 478 25 5.2 455 37 8.1
91 8.1 735 60 8.2 393 31 7.9
* Excludes neonatal deaths.
a. Every malformation was classified according
to system as follows:
I. Cardiovascular.
II. Central nervous (includes mental
de-ficiency and malformations of the eye).
III. Gastrointestinal (includes malformations
of mouth and teeth).
IV. Genitouninary.
V. Muscubo-skeletal (including nialfor-mations of skull and spine).
VI. Respiratory (including diaphnagmatic
hernia).
VII. Skin.
VIII. Miscellaneous (the only malformations
included were neoplasms, hemophilia,
erythroid dysplasia, hygnoma and
hemi-hypertrophy).
b. Where multiple malformations of a system
were present, each was counted as a separate
malformation with the following exceptions,
in which one on more defects were counted as
a single anomaly:
1. Cleft palate and harelip occurring
to-gether.
2. Hemivertebra and rib anomalies occurring
together.
3. Tetrad of Fallot.
4. Double or triple renal pelves with dOnl)le
on triple renal ureters, and absence of
kid-ney and ureter.
5. Identical nialformations of both feet or
both hands (e.g., right and left talipes
equino-vanus) were counted once but right
metatarsus yams and left talipes
equino-vanus were counted as two malformations.
Spina bifida with meningomyelocele was
counted as a separate malformation of two
systems (central nervous and
musculo-skele-tal), but the coincidental involvement of the
skin was not scored as a separate
malforma-tion of the skin.
No attempt was made to distinguish
mal-formations according to their pathogenesis,
i.e., to separate genetically transmitted
anomalies from those resulting from
modi-fication of the uterine environment.
The statistical analysis utilizes incidence rates based on several axes of classification as follows:
1. Number of infants with one on more
malformations.
2. Number of systems with omie or more
malformations.
3. Number of malformations of a specific
System Total
NuflibeT of anomalies first suspected or noted at:
Birth ti Months 12 Months Over
12 Months
Cardiovascular 42 15 20 5 ‘2
Central Nervous 65 27 21 16 1
Gastrointestinal 41 10 19 12
-(;eimitouritmar 41 29 #{149} 10 ‘2
-Musculo-skeletal 173 79 70 19 5
Respiratory 7 3 ‘2 1 1
Skin 91 36 36 15 4
Mis(ellaIl.NflIs 5 ‘2 ‘2 1
-‘I’otal 465 201 180 71 13
System. Total
Per (.entfirst suspected or noted at:
.
Birth 6 Months 12 Months Over
12 i!ont/s
Cardiovascular bOo 35.7 47.6 11 .9 4.5
(‘entral Nervous 100.() 41 .5 32.3 ‘24.6 1.6
(;Imstroilltestilmal 100.0 24.4 46.3 29.3
-(;eimitotirimiar
Musculo-skeletal
1(K).()
1 00 .0
70.7
45 .7
24.4
40 .5
4.9
1 0.9 2 .9
Respiratory
Skimm
100.0
bOo
42.9
39.6
28.5
‘39.6
14.3
16.5
14.3
4.3
IiscelIatieous 100 .0 40 .0 40 .0 20 .0
-Total 100.0 43.2 38.7 15.3 2.8
a Each malformation is counted once. There were 465 mualforniations found in 386 live born infants who
sur-TABLE IX
NUMBER OF MALFORMATIONS* OBsEIvED AMONG LIVE-HORN INFANTS BY OnGAN
vived the neonatal period.
SYSTEM AND AGE WHEN ANOMALY WAS FIRST SUSPECTED
Table IX shows the examination (birth, 6
mo., or 1 yr.) at which abnormalities were
first suspected or noted in live born
in-fants who survived the neonatal period.
Dc-cision as to the presence of a malformation
was not always made at the time it was first
suspected since many of the children were
referred to special clinics or for RG and in
some cases a longer period of observation
was deemed necessary. On the other hand,
some children discharged as normal after
the neonatal period or at six months, were
seen by other clinics or private physicians in
the interval between examinations and
mal-formations diagnosed by them were not
re-corded until the six or twelve-month study
examination.
Only 43.2% of the malformations
pre-sented signs, symptoms or RG abnormalities
which were observable at birth. This rather
surprising fact emphasizes the need for
cau-tion in making assurances of normality to
real or adoptive parents on the basis of
physical examination in the neonatal period.
Anomalies of the genitourinary system
ap-peared to be most easily diagnosed at birth,
but this group is primarily composed of
hydroceles, hypospadias and undescended
testes, and undoubtedly many clinically
silent malformations of the internal
genito-urinary organs remain undiagnosed. Less
than one-fifth (18.1%) of all malformations
were unrecognized until the follow-up
Type of Malformation Type of Malformation 41 19 I -3 1 ‘2 ‘2 11 -8 -11 -3 S ‘2 I 4 - ‘2 I 3 41 35 -- a - 4 - 4 - 3 - 4 - ‘2 - ‘2 - 1 - a I ‘2 I -15 -15 ‘2 8 -I -- a - 3 ‘2 1 - ‘2 22 1 65 19 ‘2 -‘2 3 - 8 11 -4 3 23* ‘2 1 ‘2 Ii I 4 -3 -4 -ney Hydroureter
Other malformations of ureter
Exstrophy of bladder Hypoplasia of bladder Malformations of urachus Atresia of urethra Stricture of meatus
Hypospadias
IJndescended testes
Ilydrocele
Cleft scrotum
Malformations of uterus
TABLE X
NUMBER OF MALFORMATIONS BY ORGAN SYSTEM AND TYPE
Number of
Instances Among
Still-Live- born born &
Neo-natal I)ealhs .\uinber of Instances Among Still-Lire- born l)orn ($.
.\eo-natal Deaths
I. (‘ardiovascularSsystem
Tetrad of Fallot
Patent ductus arteriosus Other malformations of
due-tus arteriosus
Coarctation of aorta
Right sided aorta
Other InBlformations of great
vessels
Malformations of valves:
aortie
pulmonary
Septal defects
Malformations of coronary vessels
Malformations of pulmonary
venous return
Endocardial fibrosis
Miscellaneous
Unclassified malformations of
heart
ii. Central Nervous System Microcephaly
Hydrocephalus
Anencephaly
Mongolism
Meningomyelocele and
men-ingoencephalocele
Other malformations of brain Microphthalmia
Cataract
Ptosis Nystagmus
Other malformations of eye
42 ‘27 III. Gastrointestinal System
3 ‘2 Harelip, alone
6 - Cleftpalate, alone Cleft palate and harelip
- ‘2 Malformations of uvula
I - Malformations of teeth
‘2 1 Tracheo-esophageal fistula
Pyloric stenosis
I 9 Ialformiiations of small
intes-testitie
- ‘2 iIalforniations of large
intes-1 1 tine
3 ‘2 NIalformnations of rectum
Omphalocele
I I Malformations of mnesetmtery
and peritoneutn
Iv. Genitourinary System
Absence of kidney
Malformations of renal pelvis
Polycystic disease of kidney
Ilydronephrosis
Other malformations of
kid-ranged from 29.3% of gastrointestinal
mal-formations not observed until 12 months to
only 4.9% of genitourinary. Malformations
of the teeth account for the late diagnoses
in the gastrointestinal group; severe mental
retardation for late diagnoses in the
cen-tral nervous system group.
The 13 malformations first suspected after
the age of one year are indication that even
with six and twelve-month follow-up
clini-cal examination, a certain number were
missed and undoubtedly longer follow-up
would have revealed additional
malforma-tions. Of the 13, four were previously
un-suspected anomalies found in three infants
173 30 J1. Respiratory System 7 5
(I 3 Thyroglossal duct or branchial
cleft 4
-- I) Atresia of larynx - 1
3 ‘2 \Ialformation of larynx 1
-I - Anomalous lobe of lung - I
‘2 1 Azygos lobe of lung I
-‘2 1 1)iaphragmatic hernia I 3
a a 3 I I’ll. Skin Pilonidal sinus I)ermnal sinus I)ermoid cyst IteratO(lerma Ectodermal dysplasia Epidermolysis huHosa Accessory nipples
Preauricular appendage or till) Preauricular fistula or
inden-tation
Crus anthelicus tertiuni
Malforniation of lobule of ear
Skin tabs VII!. Miscellaneous Sacrococcygeal teratoma Ilamnartoma (kidney) Erythroid dysplasia hemophilia Hygroma Hemihypertrophy I ‘FABLE X-(continued)
Type of Malformation
Number of Instances _1mong
Still-Lire- born born (f#{149}
Veo-natal
Deaths
Type of Malformation
.\umb(r (f Instances A mong
Still-born Lime- ct.
Neo-born natal Deaths
I‘. 51 usculo-Skeletal System Sputa bifi(la
(‘rammioschisis or crammiorachis-chisis llenlivertel)ra Spondylolisthesis Scoliosis l)ysostosis Prenmature sytiostosis
()ther nmalformnatiomis of skull
Ialformmimitions ofhip
Metatarsus varus ‘I’alipes
Polydactylismn
Syti(lIlCtyliStIi
Flexion (lefOrtl)ities of digits
Atiotniily of digits undiagnosed Internal torsion of tibia
Ialformmiatiomms of knees om
(1-bOWs
Absence of foot forticollis
Pseudoarthrosis of clavicle
Errors iii segmnemmtation of ril)s Gargoylismii
Chondrodystrophy
Klippel-Feil syndromne
Fibrous dysplasia of niaxilla
and mandible a 53 ‘25 30 ii II 8 3 1 I -I -I -1 -1 -‘) -- I
* Includes iS with Inarke(l muemital deficiency.
91 ‘2 19 -‘2 -1 -1 -5 1 - I ‘25 -17 -14 -‘2 -3 -‘2 -5 1 - I I -1 -I -1 -I
-order to determine the significance of a
heart murmur. The anomalies so discovered
were ectodermal dyspiasia, accessory
nip-pies, marked mental deficiency and
pre-auricular appendage. An additional four
anomalies were discovered accidentally
(during review of clinical charts) among
children who were being carried on regular
pediatric services or who were admitted to
the hospital after the age of one year. The
missed malformations so discovered were
as follows : hammertoe, scoliosis,
thyro-glossal cyst and lumbar dermal sinus. Other
malformations had been found by the study
team before the age of one year in two of
these children. Five anomalies were brought
to the attention of the study team by other
members of the hospital staff who saw the
children after the age of one year. The
mal-formations found in this way included
fi-brous dysplasia of mandible and maxiila,
patent ductus arteriosus, unclassified heart
malformation, dislocation of hip, and
TABLE XI
INcInENeE OF CONGENITAL MALFORMATIONS BY thtG.N SYSTEMS* AMONG
STILLBIRTHS, NEONATAL l)EATHS ANt) LIVE IlmuTits
‘i’umber of Infants With Defects of Specified System
System
Total Stillbirths Neonatal Deaths Lire Births
Cardiovascular 49 6 10 33
Central Nervous 74 S 6 6()
Gastrointestinal 55 5 I) 41
Genitourinary 57 4 14 39
Musculo-skeletal 171 S 9 154
Respiratory 1’2 - 5 7
Skin 90 ‘2 85
Miscellaneous 6 1 5
IS ‘29 356
Stillbirths .‘seonatal Deaths Lime Births
Total malformed infants 433
Per cent of Infants with (‘ongenital Malformations of Each System
System Total
Del iveries
Cardiovascular 0.9 5.4 I0.’2 0.6
Central Nervous I.3 7.‘2 6.I I.I
Gastrointestinal I.0 4.5 9.‘2 0.7
Genitourinary Musculo-skeletal
1.0 3 .0
3.6 7.‘2
14.3
9.‘2
0.7
‘2.8
Respiratory
Skiti
0.’2 1.6
-5.1
‘2.0
0.1
1.6
Miscellaneous 0.1 0.9 - 0.1
Total malformed infants 7.5 16 .‘2 ‘29.6 7.0
* The 85 infants with multiple defects are counted once in each system involved.
malformation noted during the study
fol-low-up. These 13 malformations have been
included in all rates even though they were
not found during the routine one-year
fol-low-up which all infants received.
Table X shows in detail the types of
mal-formation found in 386 live-born infants
and 47 stillbirths and neonatal deaths. In
this table each malformation is listed
sepa-rately. It is to be noted that the types of
malformation are quite different in infants
who survived as compared to those who did
not. This is due to the factors of: 1)
lethal-ity of certain defects and combinations of
defects in grossly malformed fetuses; 2)
pathological diagnoses of conditions that
could not be observed in a living child, and
3) impossibility of diagnosing at autopsy or
at an early age certain defects that
mani-fest themselves with the functional
develop-ment of the infant. The findings of this
table will be discussed in conjunction with
the incidence rates by organ system groups
shown in Table XI.
Cardiovascular system. Defects of the
cardiovascular system were found in 0.9%
of total births, 5.4% of stillbirths, 10.2% of all
neonatal deaths and 0.6% of live-born
sur-viving infants. Forty-two cardiovascular
anomalies (Table X) were observed in the
33 live-born infants (Table XI) and 27 in
16 stillbirths and neonatal deaths. Patent
ductus arteriosus and patent foramen ovale
were diagnosed only in live-born infants
surviving to six months. Malformations of
diagnoses. The 22 unclassified
malforma-tions of the heart among live born infants
were clinical diagnoses supported by
care-ful study and observation in the pediatric
cardiac clinic.
Central nervous system. The incidence of
defects of the cemitral nervous system was
1.3% of total births, 7.2% of stillbirths, 6.1%
of neonatal deaths, and 1.1% of live births.
There were 65 central nervous system
de-fects found in 60 live born infants and 19
among 14 stillbirths and neonatal deaths.
Severe mental deficiency, mongolism and
cataract together accounted for two-thirds
of the nervous system defects in the
live-born infants. Anencephaly, hydrocephaly
and meningomyelocele and
meningoenee-phalocele accounted for nearly four-fifths
of the defects in the stillbirths and neonatal
deaths. The only eases of mental deficiency
included as malformations were those that
were gross and completely obvious. The
short follow-up period did not afford an
opportunity for the detection of mild
de-grees of mental deficiency.
Gastrointestinal system. Anomalies of the
mouth and teeth are included with defects
of the gastrointestinal system. Under this
definition, 1.0% of all infants delivered were
found to have defects of the gastrointestinal
system: 4.5% of stillbirths; 9.2% of neonatal
deaths, and 0.7% of live born children.
Mal-formations of the uvula (chiefly bifid uvula),
cleft palate, harelip, and malformations of
the teeth accounted for three-fifths and
pyloric stenosis for one-quarter of the 41
malformations among live-born children.
Nomie of the live-born children was found to
have multiple defects of the system.
Nine-teen defects were identified among 14
still-births and neonatal deaths.
Genitourinary system. Defects of the
genitourinary system were found in 1.0% of
total births, 3.6% of stillbirths, 14.3% of neo-natal deaths, and 0.7% of live births.
Thirty-five defects were found among 18 stillbirths
and neonatal deaths. All of the diagnosed
malformations of the kidney and bladder
were found in this group, the great majority
being discovered at autopsy. Thirty-nine
live born children had 41 malformations of
the genitourinary system, of which all hut
three were hypospadias, undescended tests
and hydrocele. Because of the diagnostic
difficulties in the latter two conditions,
per-sistence of the finding at six and 12 months
was required for their imiclusioii.
Musculo-skeletal system. The incidence of
musculo-skeletal defects was highest of any
organ system group: 3.0% among total
births; 7.2% among stillbirths; 9.2% among
neonatal deaths, and 2.8% among live born
infants. Thirty defects of this system were
found in 17 stillbirths and neonatal deaths,
12 representing either spina bifida,
cranio-sehisis or craniorachischisis. Among 154
live-born infants with 173 musculo-skeletal
de-feets, there were 78 instances of talipes or
metatarsus varus, and 52 of polydactylism,
syndactylism or flexion deformities of the
fingers or toes. In practically all cases of
talipes and metatarsus varus the diagnosis
was verified by RG.
Respiratory system. Only 12
malforma-tions of the respiratory system were
diag-nosed, giving an incidence rate of only 0.2%
of all births. Five stillbirths and neonatal
deaths had one malformation apiece, of
which three were diaphragmatic hernia.
One anomaly of the lung was diagnosed by
RG, and one at autopsy in a neonatal death.
Four of the seven malformations in seven
live born infants were thyroglossal duct or
branchial cleft.
Skin. Skin defects were observed in 1.6%
of total births. All but two of the 91 skin
de-feets occurred among 88 live-born infants.
Two-fifths were defects of the external ear,
27% were accessory nipple, and one-fifth
were pilonidal sinus. A diagnosis of
pilonidal sinus was withheld if the end of
the tract could be visualized. Nevi were
not included as malformations.
Miscellaneous. Five live-born infants and
one stillborn infant had malformations not
classifiable in any organ system group.
These diagnoses are listed in Table X.
The results shown in Table XI may be
summarized as follows.
TABLE XII
MALFORMED STILLBIRTHS AND NEONATAL DEATHS ACCORDING TO NUMBER OF ORGAN
SYSTEMS INVOLVED AND NUMBER OF MALFORMATIONS PER INFANT
Malformations
per Infant
Vmirnber of Infants
----IJ’it/ t Involvement of:
T0 at 1
One
System,
Two Systems
Three Systems
-lour Systems
-____________
Fit’e Systems
1 16 16 - - -
-‘2 15 4 II - -
-3 5 3 1 I -
-4 ‘2 - 1 . 1 -
-5 3 - ‘2 1 -
-6 - - -
-7 1 - - I -
-8 1 - - I -
-9 ‘2 - -
-
- ‘210 I - - - I
-11 I - - - - I
Total 47 ‘23 15 5 I 3
every organ system group had a markedly
higher incidence of malformation among
neonatal deaths than among stillbirths.
Among stillbirths and neonatal deaths
com-bined, the incidence was about the same
(from 13-18%) for all organ groups except
respiratory system and skin. In live-born
infants, the pattern was quite different. The
museulo-skeletal system was affected in the
highest proportion of infants (2.8%),
fol-lowed by skin with 1.6%. This may be, in
part, a reflection of the greater ease of
diagnosis of minor external defects than
of minor internal defects. The rate of
oc-currence of malformations of the
respira-tory system is notably low.
Multiple Defects
Tables XII and XIII show for malformed
stillbirths and neonatal deaths and for
live-born malformed infants, the number of
de-fects observed and the number of organ
system groups in which defects were noted.
Of the malformed stillbirths and neonatal
deaths 66.0% and of the malformed live-born
infants 14.8% had more than one
malforma-tion. More than one system was involved
in 51.1% of the malformed stillbirths and
neonatal deaths as compared with 9.1% of
the malformed live-born infants.
Table XIV shows for each system the
numbers and percentages of defective
in-fants with a single malformation, with
mul-tiple malformations of a single system and
with multiple malformations involving more
than one system. In interpreting these tables
it should be borne in mind that each infant
is counted once in each system in which a
malformation was present. Thus the grossly
malformed infants that were stillborn or
TABLE XIII
MALFORMED Lrv BORN INFANTS ACCORDING TO
NUM-BER OF ORGAN SYSTEMS INVOLVED AND NUMBER OF
MALFORMATIONS PER INFANT
Malformations per Infant
Number of Infants With Involv ement of:
T I I0 a
One System
Two Systems
-Three Systems
1 3’29 3’29 -
-‘2 44 ‘20 ‘24
-3 8 ‘2 ‘2 4
4 3 - 1 ‘2
5 1 - 1
-6 - - -
-7 1 - 1
System
One (‘.5!. ilfu/tip/e Ilfultiple One (il. J!u/tijde ilultiple lotal ()fOne (‘.5!. of (‘.51.in Total of One (il. of (._!I. in
System One Sys- Multiple System One 5ys- Multiple Only tern Only Systems Only tern Only Systems
Stillbirths and ?‘ieonatai Deaths
16 6 4 6 100.0 37.5
14 - 1 13 100.0
-14 ‘2 - 12 100.0 14.3
18 5 ‘2 11 100(1 ‘27.8
17 ‘2 - 15 100.0 11.5
5 1 - 4 100.0 ‘20.()
‘2 - - ‘2 100.0
-Live-born Infants Surviving “ieonatal Perw(I
‘2 1’2 100.0 57.6
25.0
7.1
II .1
Cardiovascular
Central Nervous (;astroititstimimil Genitouritmary Musculo-skeletal Respiratory
Skiti
33 19
60 43
41 32
39 31
154 122
7 5
85 72
1 16 100.0
- 9 100.0
1 7 100.0
15 17 100.0
- ‘2 100(1
3 13 1(10.0
71 .7
78.0 79.5
79.2
71 .4 81 .8
6.1 36.4 1.7 26.7
- ‘22.0
2.6 17.9
9.7 11.0
- 28.6
3.4 14.8 TABLE XIV
OCCURRENCE OF M ILTI1’LE 1)EFECTS AMONG MALFORMED INFANTS BY OtwAN SYSTEE S
“,‘uniber of Infants Jiith Per (‘cut of Infants JVith
(‘ardiovascilar
Cetitral Nervous Gastrointestinal
Genitourinam V
iiisciilo-skelt t:il
Respiratory
Skin
37.5
9’2 .9
85.7
61.1 58.’2 80.0
100.0
died soon after birth may be included in
each of several systems. The circumstance
that multiple anomalies occurring in one
individual are apt to include a lethal lesion,
or one incompatible with indefinite
sur-vival, affords a plausible explanation of the
fact that the proportion of infants with a
single malformation of a single system is
low among stillbirths and neonatal deaths,
as compared with infants who survived the
neonatal period.
The relatively high proportion of
anoma-lies of the cardiovascular system or of the
genitourinary system occurring singly,
with-out any other systems being involved, in
malformed stillbirths and neonatal deaths
may depend on two interrelated
circum-stances: the serious nature of such lesions;
and the fact that their identification may
often depend on autopsy examination. The
easily observed defects of hypospadias,
un-descended testicle and hydrocele which
comprise most of the genitourinary defects
recognized in live-born children, appear
singly about as often as do defects of other
systems. Multiple defects of a system in
live born children were more frequent
among children with musculo-skeletal
de-fects than in any other organ system group.
Single defects in live-born children were
more frequent among those with skin
de-fects than in any other organ system group.
The most commonly associated
mal-formed systems were central nervous and
musculo-skeletal
(
19 cases), genitourinary and gastrointestinal (10 cases),cardiovascu-lar and central nervous (9 cases),
musculo-skeletal and genitourinary (9 eases), and
musculo-skeletal and gastrointestinal (9
cases).
Mortality
The mortality among infants with
mal-formations occurring in the various body
systems is further explored in Table XV.
The proportion that died in each group is
not a death rate due to that group of
mal-System lottil
I)ied 1-1.? .1105.
Per Cent Died
Cardiovascular 49 6 10 4 40.8
Central Nervous 74 8 6 8 29.7
Gastrointestinal 55 5 9 - ‘25.5
(;etlituritiar 57 4 14 - 31 .6
Musculo-skeletal 171 8 I) 4 12.3
Respiratory 12 - 5 I 50.0
Skiti 90 - ‘2 - 2.2
Miscellaneous 6 1 - - 16.7
Total malfornwd infants 433 1 S 29 1 2 13.6
* Infants with multiple (lefects are counted once in each system involved.
TABLE XV
l)EATIIS AMONG INFANTS WITh MALFORMATIONS BY O1IGAN SYSTEMS*
‘ . . Neonatal
Stz/lbmrtlzs
Deaths
formations it was often impossible to
de-termine which one was the cause of death.
In many stillbirths and in neonatal deaths,
the cause of death was undetermined or was
not the congenital malformation (which
may have been merely an incidental finding
at autopsy). Mortality was relatively high
among infants with anomalies of the
cardio-vascular, genitourinary and central nervous
systems. The apparently high death rate
among infants with malformations of the
respiratory system loses most of its
sig-nificance because of the small numbers
in-volved.
There were 17 deaths among the entire
group of 5,530 infants who survived the
neonatal period. Of these deaths, 12
oc-eurred among the 386 infants with
congeni-tal malformations. All three of the live-born
infants with spina bifida and
meningo-myelocele, four of the 11 mongoloids, one
of the two hydrocephalics, and one of the
three with hemivertebrae and fused ribs
died before the age of one year. Four out
of 33 with congenital heart disease died
before one year; one of these also had
mongolism and another had pulmonary
atresia. It is of interest that in three of the
12 deaths among malformed infants, the
primary cause of death was stated to be
bronchopneumonia with the congenital
mal-formation being considered as an associated
condition (one mongolism, one
con-genital heart disease, type undetermined,
and one multiple errors of segmentation of
vertebrae).
Comparison With Other Studies
Since this is the first prospective
investi-gation of the incidence of congenital
malfor-mations on a large scale, the results are
not directly comparable with those of other
workers. In other hospital studies17 data
have been taken retrospectively from
hos-pital records and there has been no
con-certed, planned effort to discover
malforma-tions either at birth or in continued
fol-low-up during the first year of life. Murphy4
obtained his data from birth and death
cer-tificates, interviews with the families or
physicians of the deceased defective
in-dividuals as well as from hospital records.
The inclusion of infants in the present study
was decided upon at or before the fourth
gestational month, with the result that the
population is not weighted by complicated
pregnancies or deliveries as are many
hos-pital populations of consecutive deliveries.
The high percentage of autopsies performed
on stillbirths and neonatal deaths does not
permit comparison of malformation rates in
even these groups with the rates found in
other studies in which information was
taken from death certificates or from
hos-pital records. Only those specific types of
be noted in any routine examination at
birth, notably anencephaly, hydrocephaly,
spma bifida, cleft palate and harelip, lend
themselves to valid comparison with the
incidence as found in other studies.
How-ever, such comparison must take into
ac-count such factors as age and parity of
mother, sex, color and calendar years of
observation as well as types of populations
studied. Space does not permit the
inclu-sion of such an analysis in the present
re-port.
SUMMARY
I. The plan is described of a prospective
study of the outcome of 5,964 pregnancies,
with special emphasis on the relationship of
factors in fetal environment to the incidence of abortions, stillbirths, neonatal mortality and congenital malformations.
II. Data are presented on the overall
in-eidenee of congenital malformations
accord-ing to sex, race, weight at delivery,
ma-ternal age and order of birth.
A. The incidence of congenital
malforma-tions among 5,739 products of conception
weighing over 500 grams was 7.5%. The rate
was 7.0% among infants born alive and
sur-viving the neonatal period, 13.6% among
antepartum deaths, 23.3% among
intra-partum deaths, 29.6% among neonatal
deaths and 70.6% among deaths occurring
between the ages of one and 12 months.
B. The following relatiomiships in
mci-denee rates among live-born infants
sur-viving the neonatal period were found.
1. The rate among males (8.4%) was half
again as high as among females (5.5%).
2. Non-white infants had a higher rate
(7.8%) than white infants (6.3%).
3. Infants weighing 2,500 grams or less
had a higher proportion with defects
(9.7%) than did those weighing over
2,500 grams (6.7%), although this
differ-ence occurred entirely among females.
4. Maternal age had no effect on the
in-cidence of congenital malformations.
5. White infants of lower birth order had
a lower rate (5.3%) than did those of
higher birth orders (8.2%). No
differ-ence according to birth order was
ob-served among non-white infants.
III. A system of classification of
malfor-mations is described and discussed.
Inci-dence rates by organ system groups are
pre-sented.
A. Less than one-half of the
malforma-tions found among live-born infants were
suspected or noted at birth.
B. Malformations of musculo-skeletal
sys-tem and skin were more frequent than
mal-formations of other systems. Incidence rates
by organ system groups are directly related
to problems of diagnosis.
C. Of the malformed live-born infants,
14.8% had more than one malformation and
in 9.1% more than one system was involved.
Of the malformed stillbirths and neonatal
deaths, 66.0% had more than one
malforma-tion and in 51.1% more than one system was
involved.
ACKNOWLEDGMENTS
The authors acknowledge with pleasure
the contribution of Mrs. Ruth P. Brooks
who was responsible for the organization
and tabulation of the statistical data and
who has been of inestimable assistance in
preparing the material for publication. We
also wish to express our gratitude to Miss
Helen Williams, Mrs. Eleanor Fries, R.N.,
and Mrs. Margaret Farley who have
as-sisted in various phases of the study, and to
Dr. William A. Silverman who has reviewed
the manuscript.
REFERENCES
1. Carter, C. 0. : Maternal states in relation to congenital malformations.
J.
Obst. &Gynaec. Brit. Emp., 57:897, 1950.
2. Worcester, Jane, Stevenson, S. S., and
Rice, R. G. : 677 congenitally malformed
infants and associated gestational
char-acteristics. PEDIATRICS, 6:208, 1950.
3. Stevenson, S. S., Worcester, Jane, and Rice,
R. G.: 677 congenitally malformed infants and associated gestational characteristics.
PEDIATRICS, 6:37, 1950.
4. Murphy, D. P. : Congenital Malformations,
521
5. Record, R. G., and MeKeown, T. :
Congeni-tal malformations of the central nervous
system. Brit.
J.
Social Med., 4:183,1949.6. Malpas, P.: The incidence of human
mal-formations and the significance of changes
in the maternal environment in their
cau-sation.
J.
Obst. & Gynaec. Brit. Emp., 44:434, 1937.7. Prematurity, Congenital Malformation and
Birth Injury. Proceedings of the
Associa-tion for the Aid of Crippled Children.
New York, J. B. Watkins Co., 1953.
8. Manual of the International Statistical
Clas-sification of Diseases, Injuries, and Causes
of Death, 6th Rev. World Health
Organi-zation. Geneva, Switzerland, 1948.
SPANISH ABSTRACT
Incidencia
de
Malformaciones
Cong#{233}nitas Estudio
de
5964Embarazos
Se presenta la incidencia de malformaciones cong#{233}nitas en los productos de 5964 embarazos
atendidos en un perlodo de 5 aflos, como parte
de un estudio para determinar Ia relaci#{243}nde
infecciones y otros padecimientos observados
durante el ambarazo con la incidencia de
abortos, nacidos muertos, prematurez,
mortali-dad infantil y malformaciones cong#{233}nitas.
Se admitid a las madres en su primer examen
hasta el cuarto mes des del embarazo, sin
dis-tinci#{243}nde raza, color y condici#{243}necon#{243}mica. Se procur#{243} recoger una historia cuidadosa sobre
padecimientos infectocontagiosos del paciente o
su familia, de preferencia en relaci#{243}n a
sarampi#{243}n, rubeola, varicela, parotiditis,
polio-mieitis y hepatitis infecciosa; asi como
acci-dentes de cualquier naturaleza observados
durante el embarazo. Los ex#{225}menesse hicieron
mensualmente hasta el octavo mes,
bisemanal-mente durante el octavo y semanariamente
hasta el octavo mes, bisemanalmente durante
el octavo y semanariamente hasta ci fin del
embarazo. El reci#{233}nnacido se
examin#{243}cuida-dosamente con particular atenci#{243}n a Ia
in-vestigaci#{243}n de malformaciones cong#{233}nitas; se anotaron peso, estatura, circunferencia cef#{225}lica y tor#{225}cica, datos radiogr#{225}ficos de cabeza y t#{243}raxy ex#{225}menes oculares; los ex#{225}menes de los ni#{241}osse repitieron a los 6 y 12 meses en clInicas especiales. Se procur#{243}examinar cuida-dosamente tambi#{233}n todo “producto p#{233}rdido”
del embarazo; los fetos de 10 cm. o menores en
longihmd fueron examinados por ci
Departa-mento de Embriologla del Instituto Carnegie de
Baltimore; los fetos mayores y los nacidos
muertos 0 fallecidos en el perlodo neonatal
fueron estudiados en el Laboratorio de
Pato-logIa del Babies Hospital. El ntimero de
au-topsias de abortos fu#{233}baja por factores difer-entes.
Se estudiaron 5964 embarazos y 6053
pro-ductos; 5878 fueron #{241}nicos,166 gemelos y 9
triates. El grupo clInico observ#{243}ci 92.4% de
los 5517 niflos vivos a los 6 meses de edad; en
159 ni#{241}os(2.9%) se recibieron informes de su
medico o de otras clInicas a los 6 y 12 meses;
. por lo tanto, solo 262 ninos (4.7%) se perdieron en el estudio.
El 55.8% de las madres fueron blancas y el
44.2% no blancas, distribuIdas en forma similar
en cuanto a edad y niimero de embarazos;
todas recibieron el mismo cuidado prenatal; el
medio ambiental en relaci#{243}n al estado
ceo-n#{243}mico y cultural fu#{233}semejante.
La incidencia de malformaciones cong#{233}nitas
en 5739 productos pesando m#{225}sde 500 gramos
fu#{233}de 7.5%; se excluyeron en este an#{225}lisis314
abortos con peso menor debido a informaci#{243}n
inadecuada sobre Ia presencia o ausencia de los
defectos cong#{233}nitos. La tabla #5 resume la re-laci#{243}nde los defectos entre los nacidos muertos,
fallecidos antes del mes de edad y naciodos
vivos que sobrevivieron ci periodo neonatal; el
porcentaje de ninos con malformaciones
au-mentd progresivamente de 13.6% de muertos
antes del parto, a 23.3% muertos al nacer, luego
a 29.6% de fallecidos dentro de los 30 dIas de
edad (en este #{241}ltimola frecuencia de
malforma-ciones fu#{233}cuatro veces mayor que Ia de los
ninos que sobrevivieron el perlodo neonatal
(7%)); por (iltimo, a 70.6% en los fallecidos entre
1 y 12 meses de edad. Las diferencias en los
porcentrajes prenatales, al nacer y neonatales,
podrIan indicar que muchas malformaciones
compatibles con Ia vida intrauterina imponen
riesgos durante el parto, mientras que otras son
incompatibles con Ia vida extrauterina.
Las malformaciones cong#{233}nitas se presentaron en el 8.4% de los ni#{241}osy 5.5% de las ni#{241}as;los
nmnos no blancos con umi porcentaje superior a
los blancos (7.8 y 6.3% respectivamente). Los
que pesaron 2,500 gramos o menos mostraromi
defectos en el 9.7%, superior a los de peso
mayor (6.7%) diferencia observada
completa-mente entre las niflas. La edad materna no
tuvo efecto sobre Ia incidencia en tanto que si
blancas ya que hubo mayor niimro de
mal-formaciones en los productos del tercero o m#{225}s
embarazos (8.2%) en contraste con lo observado
en productos de embarazos menores (5.3%); no
se encontraron diferencias significativas en
cuanto a Ia edad y n#{241}merode embarazos en
las madres consideradas no blancas.
La elasificaci#{243}n de las malformaciones
con-g#{233}nitas present#{243} dificultades diversas pues
ninguno de los sistemas usados por diversos
in-vestigadores es realmente satisfactorio. Los
autores del presente artIculo adoptaron una
propia utilizando al m#{225}ximo la informaci#{243}n re-cogida que permitiera diversos tipos de an#{225}lisis estadIsticos. Toda malformaci#{243}n se clasific#{243} de acuerdo con ci sistema afectado: cardiovacular, nervioso central, gastrointestinal, g#{233}nito-urina-rio, musculoesquel#{233}tico, respiratorio, piel y mis-cel#{225}neos; al presentarse varias malformaciones
de un sistema, se contaba cada una por
separado excepto al tratarse de paladar y
labio hendido, tetralogla de Fallot, pelvicillas
y ureteros renales m#{233}ltiples, ausencia de ri#{241}#{243}n
0 ureteros y malformaciones id#{233}nticasde pies ‘i
manos; Ia espina bIfida y ci meningomielocele
se eonsideraron diferentes para dos sistemas
(
ncrvioso central y musculoesquel#{233}tico); no sehizo distingo de las malformaciones de aeuerdo
con su patogenia. El an#{225}lisisestadIstico se
realiz#{243}en Ia forma siguiente: 1) n#{241}merode
ni#{241}oscon una 0 dos malformaciones; 2) nilmero
de sistemas on una o m#{225}smalformaciones, y
3) n#{233}mero de malformaciones de tipo especIfico
(tetralogia de Fallot, espina bIfida, etc.).
Solo el 43.2% de las malformaciones se
mani-festaron al nacer; dato que obliga al m#{233}dicoa
ser cauto en aceptar normalidad de los ni#{241}os
sobre Ia base del examen fIsico del reci#{233}n
nacido; menos de Ia quinta parte de las
mal-formaciones totales (I 8. 1%) pasaron desaperci-bidas hasta el a#{241}ode edad, fallando Ia
fre-cuencia segiin el sistema afectado. Trece
mal-formaciones encontradas o sospechadas hasta
despu#{233}s del aflo de edad indican que los
ex#{225}menes exclusivos a los 6 o 12 meses son
defeetuosos.
Se encontraron tipos de malformaci#{243}n
difer-entes en niflos sobrevivieron comparadas
con los que fallecieron; esto se debe a factores diversos: a) letalidad de algunos defectos y
combinaciones de defectos en fetos muy
de-formados; b) diagn#{243}sticos patol#{243}gicos de
con-diciones imposibles de observarse en un ni#{241}o
vivo, y por #{252}ltimo c) imposibilidad de
diag-n#{243}sticoen Ia autopsia 0 en #{233}pocastempranas de
Ia vida de algunos defectos que se manifiestan
con el desarrollo funcional de los ni#{241}os.
Las malformaciones del sistema
musculo-cs(Iuel#{233}tico y de Ia piel fimeron m#{225}sfrecuentes
(l1 las de otros sistemas; Ia incidencia de
de-fectos en grupos por #{243}rganos y sistemas se
supedit#{243} a facilidades del diagn#{243}stico. Dc los
ninos vivos con malformaciones, el 14.8%
tuvieron m#{225}sde una malformaci#{243}n y en ci 9.1% se involucr#{243} m#{225}sde un sistema; los nacidos
muertos 0 fallecidos en la perlodo neonatal que
presentaron malformaciones, tuvieron en un 66%
m#{225}sde una malformaci#{243}n y se invoiucr#{243} m#{225}s
de un sistema en ci 51.1%. Excepto para el
sistema nervioso central los dem#{225}ssistemas
pre-sentaron una imicidencia de malformaciones muy
superior en los fallecidos en ci perlodo neonatal
(lt en los nacidos muertos. Las malformaciones
multiples de varios sistemas m#{225}sfrecuentes
fueron : sistema nervioso central y
m#{241}sculo-esquel#{233}tico, genito-urinario y gastrointestinal,
cardiovascular y nervioso central,
musculo-esquel#{233}tico y g#{233}nito-urinario y
m#{241}sculoesque-l#{233}ticoy gastrointestinal. La mortalidad entre
los ni#{241}oscon malformaciones en varios sistemas
se presenta en Ia tabla #15.
Desde ci punto de vista de comparaci#{243}n con
otros estudios, los autores reconocen su
im-posibilidad va que #{233}stees el primer estudio
in-tencional en gran escala de Ia incidencia de
