A
LONG-TERM
FOLLOW-UP
STUDY
OF
SMALL
PREMATURE
INFANTS
Margaret Dann, M.D., S. Z. Levine, M.D. and Elizabeth V. New, M.A.
The New York Hospita!-Corne!l Medical Center, Department of Pediatrics
TABLE I
CLASSIFICATION OF 100 CHILDREN WITH BIRTH OR
MINIMUM WEIGHT 1,000 GM OR LESS
Sex Male
Female
Race White
Nonwhite
Birth weight, gin 660-999
1,000-1,325
Birthplace
The New York Hospital
Transferred to the N.Y.H.
Socioeconomic
Private patients Service patients
35 65
gsa
17b
45
55
34
66
68 32
aOne Puerto Rican child classified as white.
b One Cuban-Panamanian, one Filipino, 15 North
American Negroes.
(Submitted July 31; revision accepted for publication November 28, 1963.)
This study was supported in part by the Playtex Park Research Institute and by the Fund for
Pre-mature Infants (Jaffe Fund).
More complete information on these infants is supplied as Appendixes A and B, which are included
in the reprints of this paper.
ADDRESS: (M.D.) 525 East 68 Street, New York 21, N.Y.
PEDIATRICS, June 1964
945
I
N 1958’ data were reported concerningthe development of 73 children who were prematurely born with birth or post-natal weights of 1,000 gm or less (birth
weights 660 to 1,280 gm). Follow-up studies at 4 years of age or older revealed that physical health and development were in
general unimpaired, barring a high mci-dence of visual defects and of delay in at-taming average stature. Intelligence quo-tients ranged from 59 to 142, with an aver-age of 94. Full-term siblings in 34 families
had an I.Q. range of 70 to 137 and an aver-age of 107.
There was no apparent relationship
be-tween the I.Q.’s of the prematurely born
children and the following factors : year of birth, maternal illness and complications of
pregnancy or delivery, birth weights,
neo-natal complications, including jaundice, and the presence of visual or other physical defects.
Socioeconomic status appeared to play a
role: among 47 private patients, 22 (47%) had I.Q.’s of 100 or more, whereas only
5
(19%) of 26 service patients had I.Q.’s of 100 or more. The generally high socioeco-nomic status of the families was thoughtto explain the differences between the ob-servations in this study and those of Knobloch et al.,2 Douglas,3 Drillien,4 and others, who reported a high incidence of mental and neurologic handicaps in the
prematurely born.
Since the earlier report, further data have been obtained for 65 of the original 73 chil-dren, and 27 children have been added.
This paper reports the results in these 100
children, and compares the intelligence quotients of 99 of them with those of full-term siblings in 49 families.
SUBJECTS AND METHODS
All of the patients had been cared for in the Premature Nursery of The New York Hospital. Birth dates ranged from January 1, 1940, through December 31, 1957; dates
DATA CONCERNING 83 PREMATURE INFANTS NOT STUDIED IN FOLLOW-UP
31
52
67 16
946
On the first visit, a medical and social history was obtained, supplemented by data
from The New York Hospital records and from other hospitals, social agencies, and private doctors. A physical examination was performed; a satisfactory psychometric eval-uation was obtained in all except one child. The Stanford Binet Form L5 was used in nearly all; rarely, the Wechsler Intelligence
Scale for Children4 was used.
On subsequent visits, at intervals of one
year or more, similar observations were made. For 5 children, data on health and growth were obtained by questionnaire.
Sex
Male
Female
Race White
Nonwhite
EXCLUSIONS AND CONTROLS
From 1940 through 1957, 183 children who either weighed 999 gm or less at birth or fell to 1,000 gm or less in the neonatal period were discharged alive from The New York Hospital. Eighty-three have not been seen in the current study; no data are avail-able for some whose addresses are distant or unobtainable, or whose parents failed to respond to invitations. Available informa-tion about these 83 children is summarized in Table II.
In each of 49 families of the premature children examined, a full-term brother or
TABLE II
Classification
Birth weight, gm
705-999
1,000-1,445
Birthplace
The New York Hospital
Transferred to The N.Y.H.
58
31
52
Available Information re Eyes and Mentality
Year of Birth
Number of Children
No Data
“Zormal” at 6 Months
Normal Mentality
but Eye Defects N#{252}rinal Eyes but Mentally Retarded
Eye and Mental Defects
RLFb
Cicatricial Other RLFt
Cicatricial Other
1941-1949
1950-1953
1954-1957
19
3
3
7
3
13
4
8
8
3
0
1
0
4
3
5
2
1
2
0
2
Totals 83 3 0 7 1
8
12 16 4
20
Oilier Data
Seven patients are known to have died, at ages 2 months to 2 years.
Causes of death in 3 patients: toxoplasmosis, congenital heart disease, exstrophy of bladder; unknown in 4
patients.
Six patients were known to be in institutions for the mentally retarded when last heard from.
sister was given at least one psychometric examination as a “control.” Twenty-eight
were girls; 32 were older than the prema-ture child. Siblings were chosen because they had the same socioeconomic status, with the same home environment and type of pediatric care, and the same potential hereditary endowment. If the circumstances of the study had permitted the selection of full-term children in other families of the
same socioeconomic status, matching for sex, age, birth rank, and age of mother, as in the studies of Douglas and Mogford, and
also for race, this would have been desir-able. However, neither kind of “control” permits matching for complications of preg-nancy, type of delivery or neonatal care,
including oxygen.
The possible effect of differences in ages at time of testing was investigated by tim-ing return visits of the premature child or the full-term child to permit a comparison of the I.Q.’s by the same test (Stanford Binet Form L), and at the same age within one year, in 11 families.
CLASSIFICATION
Table I shows a preponderance of girls
and of white children, which is character-istic of The New York Hospital population in this weight group. All except one child born in 1955 were born in wedlock.
Sixty-eight had private physicians; the type of medical care was generally consistent with other criteria of socioeconomic level, such as father’s occupation and type of housing.
There was a high incidence of serious complications of pregnancy or delivery, 67%, even without multiple birth or breech.
These included toxemia: 13, 7 of whom re-quired cesarean section; bleeding, due to premature separation of the placenta, placenta previa or other causes: 28;
pre-mature rupture of membranes, 15; severe infections, 5; as well as others. There were
14 twin pregnancies, 5 having other com-plications, and 1 triplet birth. Breech
pres-entation was frequent, 13, including 6 in multiple births.
All of the infants except one were in
in-cubators (Davidson, Gordon Armstrong X 4
or Isolette), usually for at least 30 days. High oxygen administration was common
from July, 1949, to October, 1953. Seventy-five of the infants were described as being in “poor” or “fair” condition at birth or in the neonatal period. Physiologic jaundice of short duration was common: 58
cases; jaundice of possible clinical signifi-cance, i.e., marked, prolonged, or associated with lethargy or jerkiness, occurred in 8
infants. No bilirubin determinations were recorded.
PLAN OF OBSERVATION
As in the previous studyl the examinations were carried out in the clinic in a leisurely manner. Interviews and psychometric tests (the Revised Stanford-Binet Form L in 97
prematurely born children and 46 full-term siblings; the Wechsler Intelligence Scale for Children in 2 premature and 3 full-term children), almost always preceded the phys-ical examinations. The pediatrician and the psychologist knew which children had been
premature, but were not aware of any bias during the examinations and testing;
how-ever, no formal measures were taken to ex-elude unconscious bias.
Laboratory tests, except for urinalysis, were omitted, to allay apprehension and obtain good co-operation during the
psy-chological testing.
Eye examinations were done in the
Pedi-atric Clinic and also, in many children, in the Ophthalmology Clinic, but refraction was seldom included.
The ages at initial examinations, except
for one child of 3 years, ranged from 4 to 102 years; at re-examination, 5% to 18% years.
RESULTS
The early observations of a high
mci-dence of visual defects and marked varia-bility in rate of linear growth, with a rather low incidence of other physical deviations from normal, were confirmed by the
addi-tional studies.
PHYSICAL DATA
The onset of menarche occurred in 19,
43-5-16
44-3
48-11
49-3-5
49-11
5o-50-4-14
50-10-1
.50-1-I3
51-3-8
53-10
55-6-19
55-10
55-11 F
M
F
F
F
F
F
M
M
M
F
F
F F
M
F
67
88
110
84
110
83
98
100
80
109
97
95
Retrolental fibroplasia; spastic
di-plegia; convulsive disorder. Died at age 134 years.
Convulsive disorder. onset at 18 months.
Hearing defect, nerve, severe.
(Re-ceived streptomycin.)
Cerebral paisy, mild (tight Achilles’ tendon.)
Pseudohermapliroditism.
Convulsive disorder, onset at age 9 sears.
Frequent respiratory infections
+poor weight gain, to age 5 years; subsequent good health and gain.
Bronchitis; pleural effusion.
Erb’s palsy, recovered. Convulsive disorder, onset at age 6 years.
Possible ventricular septal (lefect,
asymptomatic.
Hypoglycemia, prior to age 5; none
since.
hearing defect, nerve, mild.
(Re-ceived streptomycin.)
(‘erebral palsy, mild, hypotonic. Convulsive disorder, onset at 3years.
Ilypospadias.
Asthmatic bronchitis.
SEach patient is designated by a code number consisting of the
year and month of birth, with day if necessary, and the letter A or
B to indicate the first or second born, respectively, of a multiple
birth. 948
of the 24 girls who were examined or whose mothers answered questionnaires when the patients were 12 years or older. Six attained menarche between the ages of 9 and 12
years, and one at age 17; the remainder were between 12 and 14% years.
In the entire group of 100, significant de-fects in addition to visual ones were noted in 16.
Patieni
Sex I.Q. Physical Defects or Symptoms
Three patients had cerebral palsy; one (No. 43-5-16), who had a severe spastic
diplegia, also had a convulsive disorder. This patient was the only one in the series
of 100 who died. Four other children had convulsive disorders; in patient 50-12-13 there was only one convulsion at 6 years, following head trauma, and the diagnosis
by history, neurologic examination, and
E.E.C. was Jacksonian seizure disorder; in
patient 50-2, the onset was at 9% years. These appeared unrelated to prematurity.
The only one of the 7 patients with either cerebal palsy or convulsions in whom sig-nificant jaundice had occurred in the neo-natal period was patient 49-3-5, who had
jaundice with lethargy from age 5 to 13 days. Her spasticity was very slight; her I.Q., 110. Conversely, all of the other 8 patients who had demonstrated significant jaundice were free from neurologic defects at ages 4 to 10 years; I.Q.’s ranged from 80 to 120.
One child had two episodes of loss of consciousness associated with hypogly-cemia. Two children with nerve deafness or partial hearing loss, Nos. 48-11 and 53-10, had received streptomycin, the former
20 mg twice daily from age 2 to 9 days, and the latter 20 mg daily from age 0 to 22
days.
One of the original 73 patients, No. 51-3-8, had a loud systolic murmur, and at age 10 years a diagnosis of probable
interven-tricular septal defect was made. He was of normal height and weight and asympto-matic.
VISUAL DEFECTS
Table III shows the results of the most
recent eye examinations in 100 children. The 59% incidence of serious visual im-pairment was an increase over the 52%
(38/73) reported in 1958.’ This is largely
accounted for by the discovery of previously undetected defects among the 73 original
patients. Nine children whose eyes had been described as normal at ages 4 to 6
years have been discovered to have myopia,
strabismus, or astigmatism, and 2 others with known visual defects had increases in
severity: a boy born in 1948, who was al-most completely blind as a result of
TABLE III
EXAMINATION OF THE Ey:.s OF 100 CHILDREN
OF Low BIRTH WEIGHT*
949
hyphema at age 11, and a girl born in 1952 had an increase in size of a unilateral cata-ract.
In contrast, there was a decrease in mci-dence of visual handicaps in children horn in 1955 through 1957; of 16, 11 had no
de-tectable eye defect, 4 had strabismus and 1 myopia. None of these 16 had evidence of
retrolental fibroplasia in early infancy. A relationship between early active retrolental fibroplasia, which apparently regressed, and later defects, is not established, but it is of interest that of 19 children, born in 1949
through 1954, who had this condition, only 5 were found later to have normal eyes.
LINEAR GROWTH
Table IV summarizes the height data for 100 children : 84% are known to have achieved a stature above - 1 S.D.
(
16thpercentile); race, sex, and initial birth weight, within ranges 660 to 999 gm and
1,000 to 1,325 gm, did not appear to affect the outcome. Forty-four children reached the mean, and 21 of these were above +1 S.D. (84th percentile). The ages at which
these heights were attained varied. Twenty-three of the 84 were known to have reached “normal” stature, (at least the 16th percen-tile or - 1 S.D.), by the end of the third
year; 33 were known to have been below
- 1 S.D. at ages from 4 to 15 but later at-tamed at least that level; 28 who had at-tamed it, when first seen, at ages ranging from 4 to 7, may have been within the nor-ma! range prior to those ages.
Of the 16 children whose heights were below the 16th percentile when last ex-amined, 6 were over 8 years of age; 4 of
0 The Iowa Scale of Jackson and Kelly’ was used. This scale, available from the start of the
study, with individual growth charts in the metric
as well as the English system, fitted our patients’
socioeconomic level, and contained a range from
-1 S.D. (16th percentile) to +1 S.D. (84th per-centile). More recent scales (Falkner5’ 10) given in the English system only, are derived in part from the Iowa scale; mean heights for boys from age
5
to 12 years and girls from 5 to 16 years (exceptage 13) are within 0.6 in. of those on the Iowa
Scale.
Itirik Weight Findings at .1ge Number of
3 Years or Older Children
6&) to 999
1000 to
1,32o
Normal 39 15 24
Minor defects 2 1 1
Serious defects
Total
Defect
59 29 30
100 45 55
Incidence of Serious Defectst (No.)
RLF Ii
Myopia 20
Strabismus 37
Cataract 2
Astigmatism 3
Total Defects 73
* RLF= retrolental fibropLasia, cicatricial.
t In each of 8 children 2 serious defects mere found
and in each of 3 children, 3 serious defects were found
these and 2 younger children had heights below -2 S.D. (3rd percentile).
MENTAL DEVELOPMENT
Mental development, as measured by the first psychometric test after the age of 4
(
except for one patient born in 1948 whose only satisfactory examination was at the age of 3), varied widely (Table V). The I.Q. range for 99 prematurely born children was 59 to 142, with an average of 94.8, while the I.Q.’s of 49 full-term siblingsranged from 70 to 137, with an average of 106.9. The exclusion of 2 premature
chil-dren and 3 full-term siblings who were given the Wechsler Intelligence Scale for Children test rather than the Stanford Binet Form L did not alter either range, and gave
virtually identical averages of 94.9 and 106.9 respectively.
When the original studyl of 73 prema-turely born children and 34 full-term sib-lings was made, insufficient time had elapsed to determine whether increasing
tested initially at 4 to 5 years of age, would reveal significant changes in I.Q. For this reason a number of repeated psychometric tests were done. Of the prematurely born children, 41 had a second and 9 a third Stanford Binet Form L test at ages ranging from 5 to 12 years; 15 full-term siblings were retested at least once. In 26 premature
children and 7 siblings the second I.Q.
dif-fered from the first by 5 points or less and in 12 prematures and 7 siblings, there was a change of 6 to 10 points. In 4 children, 3 premature and 1 full term, the change was greater than 10 points. Positive and
nega-tive changes were about equal. On a third Stanford Binet test, 6 of 9 prematures and
4 of 5 full-term children showed a change
in I.Q. of plus or minus 6 or less. The
great-TABLE IV
HEIGHT ATTAINMENT, 100 CHILDREN OF BIRTH OR MINIMUM WEIGIIT 1000 GRAMS 011 LESS
. Year of Life
Children Attaining at Least -1 S.D. (16th percentile)
Number of Children Reaching:
-1
S.D. (16th percentile) Mean +1 S.D(8th percentile) Total . White Non-. wnlte Birth Weight 999 gm or Less Birth Weight 1000 gm or More Male Female 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th 16th 8 7 8 18* 27* 3 4 5 2 0 1 0 0 1 7 6 5 14 25 3 3 4 1 1 1 1 1 3 4 2 0 1 1 1 0 0 3 4 4 8 10 2 1 2 1 1 1 5 3 4 10 17 1 3 3 1 0 0 3 1 1 5 11 0 3 4 1 0 0 5 6 7 13 16 3 1 1 1 1 1 0 ‘2 3 4 20 6 3 4 0 1 0 1 0 0 0 0 0 1 5 6 3 3 0 1 0 0 2 0 Total Attained:
Total in Group:
%
Attained: 84 100 84 70 83 84 14 17 82 37 45 82 47 55 85 29 35 83 55 65 85 44 100 44 21 100 21Children Failing to Attain - 1 S.D. (16th percentile)t
Age at Last Visit (yr): Total White Nonwhite
4to 534 6to 7-8to 9-10to11 7 S 3 3 5(1) 2(2) 3(1) 3(2) 2 1 0 0
Totals 16 13 3
* At least 27 children first seen at ages 3 to 4ff, and one child first seen at 7 years, may have attained “normal”
height at an earlier age.
tSix white children, 3 boys and S girls, were below -2 S.D. (3rd percentile). Numbers shown in parentheses for
TABLE V
(‘osII’utIsoN OF PIIE%IATURES WITh THEIR FuIr.-TmtM SInIINGs AND WITh PREMATIUES Wno hAl) No SIBLINGS TESTED
Number of
Patients
Range
Numbers in Each I.Q. Group
---
-Average
.
5()-79 80-89 90-99 100-109 110-119120-142
Full-term siblings
Prematures with tested
siblings
Prematures without tested sihlmgs
Total prematures
49
50
49
99
70-137
64-132
59-142
59-142
1
6
7
13
4
15
13
28
13
11
9
20
12
12
11
23
6
3
5
8
13
3
4
7
106.9
94.0
95.8
94.8
aIncludes one pair of twins.
est changes in
I.Q.
were noted in prema- The I.Q. ranges, from 64 to 113 in theture male twins born in 1949; twin A prematures and from 83 to 132 in the con-showed a rise of 13 points (from 82 to 95) trols, and the averages, 95.5 in the former
between ages ‘12 and 62, and twin B and 107.4 in the latter (Table VI), were rose 15 points
(
from 96 to 111) in the same similar to the data for the entire sample interval. The only explanation is that the (Table V). The average difference of aboutenvironment is an intellectually and socially 12 points between the full-term control and
stimulating one. the premature child was also almost
identi-In 11 families the second Stanford Binet cal. This is evidence that similarity of age Form L examination was performed when when tested does not affect the results.
either the premature or the full-term child A comparison of the premature and full-had reached an age within one year of that term children in the 49 families is shown of his brother or sister when previously graphically in Figure 1. A circle on the
tested. diagonal represents a family in which the
TABLE VI
COMPARISON WITH SIBLINGS AT ABOUT SAME AGE
.
Patient
Sex
Premature Sibling
Sibling
Older or
I
ounger
Intelligence Tests
Premature Szbls. .ng Ds,fference.
. Stblzng
Minus Pre,,i. Age
(yr)
Age (yr)
,
‘e
43-5-16 F F 0 9 74t 10 98 24
43-10 F I%I Y 7f 84 7 90b 6
49-5-2 F F 0 7 91t 8 100 9
49-5-4A F iI Y Ti1 105 4i3r 132 27
50-3 F F Y 4 102 4H 83 -19
SO-hA F M Y 5 113 5j 119f 6
50-12-13 M 1I 0 5 102t 5.’ 12! 19
52-1-13 i%I F Y 5j4 64 5 92 28
52-1-24 F M Y 5 111 5 130 19
53-10 F M Y 46 109 4 120 11
55-6-5 M M Y 4 96 4 96 0
a, older; Y, younger.
0 0
70
+ -
-60 70 80 90 +00 ru 20 +30 40
I0, S/8L196
952
FOLLOW-UP
OF PREMATURES
60
50
FIG. 1. Intelligence quotients in 50 prematurely
born children and 49 full-term siblings. Each circle
represents the I.Q. of a premature child plotted
against that of his sibling, except that one point represents the average I.Q. of premature twins plotted against that of their sibling (89, average of
82 and 96, against 109).
I.Q.’s of the premature and the control were
identical; 9 circles above and to the left represent those in which the premature child had an I.Q. higher than that of his
full-term sibling; 39 circles to the right and below the diagonal, families in which the I.Q.’s of the prematures were lower.
COMMENT
This follow-up study, extended to 100 children of low birth weight, some followed to 18% years of age, largely confirms the results reported in 73 children.1
Serious visual abnormalities were even more frequent; 59% (previously 52%) had either retrolental fibroplasia, myopia, stra-bismus, or other defects; 11 children had 2 or more defects. However, treatment re-suited in adequate vision in most of those
with strabismus or refractive errors. Linear growth varied greatly; inspection
of individual growth curves revealed in many children a steeper slope than the standard; some of those who exemplified
this were the 33 patients whose height was below the 16th percentile at ages 4 to 15 years but who attained a normal height; .in 10 who were still below the 16th percentile
when last seen, a prediction of eventual
normal stature seemed warranted, while 6 might be destined to be short adults. In any given child, the growth curve plus
roent-genographic examinations for bone age might be of prognostic value.
Onset of puberty in 19 girls occurred within the same age range as in full-term
children.
Cerebral palsy in 3 children, convulsive disorders in 4 others, and loss of COnSCiOUS-ness associated with hypoglycemia in 1,
were the only neurologic disorders. In 3 of
these the disorder seemed probably
unre-lated to prematurity. Two children had nerve deafness, possibly related to
strepto-mycin administration in infancy.
Other physical defects, including
respira-tory ailments, were no more frequent than
in the general population.
The most interesting aspect of this study
concerns mental development. The ranges,
averages, and distribution of I.Q.’s in 99 prematurely born children and 49 full-term
siblings were virtually identical with the results reported in 73 prematures and 34 siblings.l The decision to use, for purposes of analysis, the first I.Q. value obtained after the age of 4 years, seems a valid one in view of the close similarity of results of repeated psychometric tests in most of the
original subjects retested.
The 99 I.Q.’s were tabulated by groups
in ascending order to examine relationships to socioeconomic status, sex, race, birth weight, birth years, and complications of pregnancy and delivery (Table VII).
A comparison of the effect of these van-ables in 99 patients with the conclusions from a similar analysis in the first 73 pa-tients shows that socioeconomic status
SoCic3ec000miC Birthireight Years of Birth I.Q. 50-59 60-69 70-79 80-89 90-99 100-109 110-119 110-19 130- 139 140- 149 rNumber of rPatie,,ts 4 8 ‘20 23 8 4 2 .vo Sex
Pruate Private ---__________
Doctor Doctor if F
0 1 1 0
2 2 2 2
I 7 3 .5
18 10 9 19
13 7 7 13
19 4 10 13
7 1 3 5
4 0 0 4
2 0 0 2
I 0 0 1
Race 11’ .VonJJ 0 1 3 I 4 4 22 6 16 4 22 1 8 0 4 0 2 0 I 0 999 gn or less 0 4 3 1.5 10 8 0 1,000 gm or more 0 .5 13 10 15 .5 3 1940-1949 0 6 10 9 II 2 0 1950- 1954-1953 1957 I 0 3 0 I 1 12 6 6 5 8 4 4 2 2 1 I 0 1 0 Maternal Complications
.‘ricusH .ifinort None
0 0 1
4 0 0
8 0 0
20 3 .5
13 2 5
13 4 6
5 1 2
2 1 1
I 0 1
1 0 0
34 83 67 SI 49 27 32 84 16 22 13 35 63 37 39 25 64 61 39 4.5 37 82 55 45 16 17 94 6 9Oorless 61
100 or more 38
total 99
%99 or less 62
%I00ormore 38
S Toxemia, bleeding, infection, premature rupture of membranes and precipitate delivery: serious.
t Breech or multiple birth: minor.
32 13 43 71 29 29 23 54 54 46 26 15 41 63 37 23 16 39 59 41 12 19 63 37 45 22 67 67 31 5 6 11 45 55 Ii 10 21 52 48 TABLE VII I.Q. Gnores AND VARIABLES
109.3, while in the service families, 9 of 14
full-term siblings
(
64%) had I.Q.’s below 100, the average I.Q. being 101.1.In the current study, percentages of males and females with I.Q.’s below 100 were al-most identical. The slight apparent advan-tage of girls over boys in the the first 73
cases was not borne out.
Although race appeared to have an im-portant influence, this is probably not the
correct interpretation. There were only 17 nonwhite children, and among these fami-lies only 2 were able to afford private
mcd-ical care; it is likely that the difference is secondary to socioeconomic privilege.
A
slightly higher percentage of I.Q.’s under 100 appeared with differences in birth weight: 71% in those under 1,000 gm at birth, compared with 54% in those of1,000 gm or more, and with 62% in the
whole group.
Years of birth, separated into periods be-fore, during, and after the era of high
oxy-gen administration, showed practically no difference.
A history of a seriously complicated
preg-nancy was present in 67%. Such a history was associated with an I.Q. below 100 in 45
(
67%). Toxemia, for example was present in 13 mothers, 9 of whom produced children with I.Q.’s of 99 or less. This was consistentwith the trend noted in the earlier report. Several recent reports of the later health of prematures reveal a high incidence of handicaps and morbidity. Knobloch et al. found many visual, neunologic, and intel-lectual deficits among Baltimore children who had been prematurely born; the mci-dence was highest among those of lowest
birth weight. Follow-up studies by
Dnil-411 in Edinburgh, at preschool and school ages, showed a similar picture.
J
ames,12 surveying 390 Negro premature in-fants and 424 full-term controls in Dallas, found a high incidence of lower respiratory and diarrheal disorders, with twice as many deaths or readmissions to the hospital among the prematurely born as among the full-term children.McDonald3 reported that, of 1,081 British children whose birth weight was 4 lb or less, more than 22% had either neurologic or ophthalmic disorders.
Examination by Lubchenko and
mci-954
FOLLOW-UP
OF PREMATURES
dence and severity of visual and central nervous system handicaps, retarded growth, and social, emotional, and school problems.
The high incidence of visual defects in the present series is similar to that found
by others, but in contrast, other physical
handicaps are less frequent, and the range
of mental development is higher. This may be in part attributed to a generally high
socioeconomic level in our series. In addi-tion, as Dnillienhl points out, the group is a selected one, even among low-birth-weight
survivors in The New York Hospital Pre-mature Nursery.
A survey of the available information concerning the 83 patients not seen (Table II) reveals that a selection on the basis of ability and willingness to participate in a follow-up study of this type inevitably leaves out many of the least successful: those who died, those in institutions, a number whose parents were unwilling to bring them to the clinic, and doubtless some of those without known address.
This selection, and the high
socioeco-nomic level, render difficult a comparison with the other studies. The high incidence of mental deficiency among the 83 children not seen, along with the superiority, on the
average, of full-term siblings to the prema-turely born children who were examined, suggests that very low birth weight in-creases the chance of mental handicap.
SUMMARY
One hundred children, prematurely born, with birth or minimum weights of 1,000 gm or less, of 183 discharged alive from the Premature Nursery of The New York Hos-pital from 1940 through 1957, were cx-amined between 1950 and 1962. Historical
and social data and findings on physical and psychometric examinations were evaluated.
With rare exceptions, physical health was good; only 3 patients had cerebral palsy; one of these and 4 others had convulsions, but in 2 of these the convulsive disorder
ap-peared unrelated to prematurity.
The children exhibited a tendency to
catch up in height to normal standards for
chronologic age, but often not until after 4
years of age.
The incidence of eye defects was 59%; the most frequent were retrolental fibroplasia,
strabismus, and myopia.
Intelligence quotients determined in 99
of the prematurely born children showed a wide range (59 to 142); the average I.Q., 94.8, was significantly below the I.Q. of
106.9 found in 49 full-term sibling controls. These values were not appreciably altered by retesting, by adding more younger
sib-lings, or by comparing premature with sib-ling on tests done at similar ages. Thirteen of the 99 prematurely born children had I.Q.’s below 80; among the 83 of similar birth weight but not available for examina-tion, 32 were known to be mentally re-tarded and 6 of these were in institutions.
The most important variable appeared to be the socioeconomic status; a significantly higher proportion of the premature children
with I.Q.’s above 100 was found among
families who had private medical care. An apparent advantage of white over nonwhite
children was interpreted as secondary to socioeconomic level.
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