(
Received April 19, 1971 ;revision accepted for publication May 19, 1972.)Supported in part by United States Public Health Service grants HD-00050-l0, AM-00795, AM-05391,
and RR-0076.
ADDRESS FOR REPRINTS: H.A.G., Ben Taub Hospital, Baylor College of Medicine, Texas Medical Center, houston, Texas 77025.
PEDL&TIUCS, Vol. 50, No. 4, October 1972 584
VITAMIN
B12 AND
FOLIC
ACID
VALUES
IN PREMATURE
INFANTS
Ambadas Pathak, M.D., and Herman A. Godwin, M.D. with the assistance of Luis M. Prudent, M.D.
From the Neonatal Research Laboratory, Boston Hospital for Women, Lying-In Divirion, and the Thor’ndike Memorial Laboratory, Harvard Medical Service, Boston City Hospital, and the
Departments of Pediatrics and Medicine, Harvard Medical School, Boston, Massachusetts
ABSTRACT. The relationship of serum vitamin
B12 and folic acid was studied in 24 premature
infants. In 14 of the 24, low serum vitamin B,2
values were found around 40 days of age. Serum
folic acid concentrations were less frequently
de-pressed and were usually associated with normal
red cell folate values. No correlation between
hematocrits and vitamin B,2 or folate levels was
found. It is suggested that low concentrations of
serum folate and vitamin B,2 result from low
dietary intake coupled with increased demand by
the prematurely born infant. Pediatrics, 50:584, 1972, VITAMIN B,,, FOLIC ACID, RED CELL FOLATE, PREMATURE INFANTS, ANEMIA.
NEMIA, considered to be “physiologic,”
develops in full-term infants during
the neonatal period.’ Premature infants
tend to have exaggeration of the anemia
even though initial cord hemoglobin values
may be the same as in full-term babies.’
The usual explanations for accentuation of
anemia in prematures involve a relatively
lower initial hemoglobin mass, decreased
hemoglobin synthesis in the first weeks of
life, and rapid growth and expansion of
blood volume.’ Iron deficiency does not
ap-pear to play a role in this early phase of
anemia though it does become important if
anemia persists or recurs beyond 3 or 4
months of age.1’
The possible role of vitamin B,2 and folic
acid in the early anemia has not been
ade-quately evaluated. Low levels of serum
folic acid have been noted in some
in-stances, but the contribution of this factor
to the anemia is debatable.46 Low serum
vitamin B12 levels were detected by Chitis
and Canosa6 in five anemic premature
in-fants, in one of whom there were
megalo-blastic changes in the bone marrow. The
purpose of this study is to examine further
the relationship of vitamin B1, and folic
acid to anemia in premature infants.
MATERIALS AND METHODS
All infants in this study were born and
re-ceived initial care at the Boston Hospital
for Women, Lying-In Division. Following
discharge, their management was, in
gen-eral, directed by private pediatricians.
Twenty-three of 24 mothers had received
adequate prenatal care and all were in
good health with no history of hematologic
difficulties.
The premature infants chosen for study
(
less than 37 weeks’ gestation ) were ingood health at the time of evaluation. To
determine the ranges of serum vitamin B
and folic acid in asymptomatic premature
infants in the nursery, a first group of 14
ba-bies (group I), ranging in ages from 16 to
62 days
(
mean 33 days)
, was examined.Those with low levels of either vitamin
were studied again at varying intervals.
Croup II, consisting of ten other
prema-ture infants, was studied prospectively
be-ginning within the first 24 hours after birth.
ma-ARTICLES 585
TABLE I
SERUM VITAMIN B12 AND FOLIC ACID VALUES IN 14 ASYMPTOMATIC PItEIATcuE INFANTS OBTAINED 16 TO 6 DAYS FOLLOWING BIRTh
‘
Group Geslalional Age, weeks
Birth Weight,
gm
In!erval From Birth toStudy,
days
Serum B12, pg/mi
Serum Folic .1cM, ng/ml
IA (5) Mean
Range
29
6-33
1,810
964-1,758
S
1-S9
268
01-401
11.0
6.0-15.5
IB(9) Mean
Range
81
28-36
1,339
680-2,098
38
16-6
104
49-155
1.9
5.3-64.5
jor problem
(
e.g., respiratory distress,sep-sis, erythroblastosis fetalis, etc.
)
waspres-ent. In eight instances, paired blood
sam-pies were obtained from neonate and
mother during the first day. Based on
infor-mation obtained from group I, second
stud-ies of these infants were delayed for a mean
interval of 40 days (range, 21 to 60 days);
those infants having low levels of vitamin
B,, or folic acid were then further
evalu-ated.
Venous blood (3 ml) was obtained from
the antecubital vein for hematologic
evalu-ation and determination of vitamin levels.
Serum vitamin B,, was assayed with
Eu-glena gracilis Z strain
(
adult values 200 to900 pg/mI) while serum folic acid was
measured by the method of Herbert (adult
values 6 to 16 ng/ml) and red cell folate by
the method of Hoffbrand and co-workers8
(
adult values 160 to 640 ng/ml).Mater-nal venous blood obtained in the paired
specimens was assayed for serum B,,,
Se-rum and red cell folate, and intrinsic factor
antibody.#{176} Unstimulated gastric juice
speci-mens were obtained from five neonates in
group II within the first 24 hours of life for
determination of pH and the presence of
intrinsic factor.9
All infants of both groups were fed a
standard evaporated milk formula#{176}
con-taming approximately 130i.g/liter folic acid
and 0.73g/liter vitamin B,,. During the
second week of life they received a daily
0.3-
to 0.6-ml dose of a multivitaminprep-arationf free of folic acid and vitamin B,,.
Administration of elemental iron was
gen-erally delayed until the birth weight was
doubled. Solids were offered, in the form
of cereals, at age 4 to 6 weeks when weights
exceeded 2,500 gm, vegetables and fruits at
6 to 8 weeks of age, and meat at 10 to 12
weeks of age.
RESULTS
The results obtained with group I arc
summarized in Table I. Of the 14 babies,
five (IA) when initially studied had serum
vitamin B,, and folic acid levels exceeding
normal adult values and were not further
evaluated. Among the remaining nine
(
lB),one had a serum folic acid less than 6 ngl
ml (5.3 ng/ml) with a red cell folate of 216
ng/ml. However, all nine had vitamin B1,
levels less than 200 pg/ml
(
mean 104 pg/ml) with four of these being less than 100
pg/mi. Evaluation of seven of the nine
in-fants at 13 to 15 months revealed return of
serum vitamin B,, to levels exceeding 200
pg/mi. In the other two infants, earlier
sub-sequent determinations demonstrated
con-tinued reduction of serum B1, levels at 54
days and at 61 and 89 days, respectively
(
Fig. 1)
. Spontaneous return toconcentra-tions above 200 pg/mi was found by 83
and 102 days after birth, respectively. No
correlation was apparent between serum
vi-tamin B1, levels and hematocrit values, and
peripheral blood smears did not show oval
a Similac, Ross Laboratories, Columbus, Ohio. f Trivisol, Mead Johnson Laboratories,
AGE (Days)
I000
- 500
“4
I00
50
FIG. 1. Serum vitamin B2 values in premature
infants. Nine of ten infants studied within 24
hours after birth (dark circles ) had normal to
increased vitamin levels. Vitamin B2
concentra-tions decreased in all nine (mean, 40 days)
reaching an abnormal range in five. Two other
infants with low serum B12 detected after birth
(
open circles ) are also shown. Spontaneousre-turn to normal values occurred in all infants
usually iy three to four months.
macrocytes or hypersegmented
polymor-phonuclear neutrophils.
Data from the study of group II are
pre-sented in Table II and Figure 1. At the time
of initial evaluation
(
day 1),
nine of tenneonates had serum vitamin B,, levels
cx-ceeding 200 pg/mi. In two babies
(
C andL
)
, an unexplained elevation of levelsabove 900 pg/mi was present. One infant
had a value of 132 pg/mi with no maternal
history for inadequate dietary intake or
malabsorption. Intrinsic factor antibody
was not detected in the mother’s serum, but
further evaluation of this mother was not
possible. In the eight cases in which paired
sera from mother and newborn were
ob-tamed, the serum vitamin B, value was
al-ways greater in the infant. All ten babies
had serum folate concentrations exceeding
6 ng/ml.
Second samples obtained at a mean age
of 40 days showed a decrease in serum
vita-mm B2 and folic acid concentrations in
nine babies. In five of these nine, serum B
fell below 200 pg/mi reaching a level of
77 pg/mi in one infant. One of the babies
with a B,, level of 115 pg/mI also had a
serum folate of 2.2 ng/ml. Of the four
re-maining infants with B,, values above 200
pg/ml, two had serum folic acid values of
3.3 and 3.4 ng/ml, respectively, with red cell
folate concentrations exceeding 160 ng/ml.
There were no detectable differences in
clinical or hematologic status between those
in whom serum vitamin concentrations
de-creased below the accepted normal adult
values and those in whom values remained
above these levels. Specifically, there was
no correlation of vitamin levels with
hema-tocrit, and peripheral blood smears did not
show oval macrocytes or hypersegmented
poiymorphs.
Serum vitamin B,, concentrations
re-turned to levels exceeding 200 pg/mi in all
five infants, generally by the age of 3 to 4
months. Serum folate remained below 6 ng
/1111
(
3.6) in one infant for 60 days with asimultaneously determined red cell folate
being 205 ng/ml.
All gastric aspirates obtained from
neo-nates in group II contained intrinsic factor
(
five infants)
and acid. Eight maternal seradid not contain intrinsic factor antibodies.
There was no proteinuria in any of the
in-fants with low vitamin B12 levels. All
in-fants followed in both groups were
devel-oping normally during the period of study.
DISCUSSION
During the first two months postnatally,
serum vitamin B,, concentrations were less
than 200 pg/mi in 14 of 24 premature
in-fants
(
groups I and II combined)
. In fiveinfants the concentrations (less than 100 pg
/mi) were those usually seen only in
pa-tients with pernicious anemia or
malabsorp-tive states. Among ten infants in whom the
initial blood specimen was obtained on the
ARTICLES 587
TABLE II
SERUM VITAMIN B1, AND FoLIc ACID VALUES IN TEN PREMATURE INFANTS STUDIED PROSPECrIVELY, PAIRED
SAMPLES WERE OBTAINED FROM THE NEONATE AND MOTHER DURING THE FIRST DAY IN EIGHT CASES
. Gestational . Age, weeks . Birth , . i eight, gm I
-
nitial Values-
Interval, days Second---infant B,,, pg/mi Values Maternal B,2, pg/mi infant B12, pg/in1
-infant Folic . Acid, ng/ini
---infant Folic . Acid, ng/inl A C (1 Wh \Vi 11 L MeN It Me 34 37 32 36 31 33 30 29 34 33 1,857 1,587 1,871 1,828 1,375 1,701 1,701 1,049 1,658 1,701 11 153 ‘233 ‘248 -138 -268 194 50 36 2,760 384 341 232 301 1,196 976 904 132 66 300 245 300 11.0 110 245 18.8 270 110 60 42 35 43 35 42 28 ‘21 37 56 1’ 77 168 126 115 ‘276 509 624 216 391 23 15.5 22 6.6 2.2 3.3 3.4 27 7.9 62
Mean 33 1,633 176 7 168 40 26 17.3
lower vitamin B,, level at the time of a
see-ond sample, even though only five of the
group reached a level less than 200 pg/ml.
Other workers have commented on a
de-dine in serum vitamin B1, values during
the neonatal period but did not report such
low levels.10 As has been previously
re-ported,11 all first-day samples from the
in-fants contained a greater concentration of
vitamin B,, than found to be in maternal
blood.
There was a spontaneous rise to normal
adult serum B,, concentrations with
ad-vancing age and increasing dietary intake.
The time interval required for achieving
such B,, levels was between three and four
months. The hematologic significance of
re-duced serum vitamin B,, was not clinically
apparent in that there were no significant
differences in hematological values in
in-fants with B,, levels either above or below
200 pg/mi. Megalobiastic changes in bone
marrow, which was not examined, could
have occurred, however, without any
reflec-tion of this in the peripheral blood.
The explanation for the postnatal
de-crease in vitamin B1, concentration is not
clear. The possible causes for a reduction in
serum vitamin B,, level include
(
1)
defec-five absorption due either to a deficiency of
intrinsic factor or to intestinal
malabsorp-tion,
(
2) abnormalities of serum binders forB,2, (3) intake of diets deficient in animal
or bacterial products, (4
)
increasedre-quirements for B,,, or
(
5)
a combination of two or more of these factors.Defective absorption seems an unlikely
explanation for the decrease in serum
vita-mm B,, among the infants in this study.
In-trinsic factor and acid were present in the
gastric secretions of five neonates evaluated
on the day of birth. Although outputs of
in-trmnsic factor and hydrochloric acid are low
the first day of life, a gradual and sustained
increase in production of these glandular
secretory components begins immediately
so that at 2 to 3 months of age infants have
intrinsic factor levels comparable to those
observed in older children and aduits.’2
Furthermore, by the second week, the
aver-age infant has intrinsic factor output
suffi-cient to ensure absorption of an adequate
amount of vitamin B,,. Intestinal
malab-sorption of vitamin B,, also seems
improba-bie. There was no history for
gastrointesti-nal abnormalities in any infant and all
babies were growing normally during the
period of study.
Differences in the serum binders of
vita-mm B,, in newborn infants have been
re-ported.13 In addition to the two normal
588
B,, AND FOLIC ACID IN PREMATURESII, a third, or “fetal,” binder has been
noted. This binder is the same size as
trans-cobalamin I, but it does not contain
endog-enous B,, nor does it transfer B,, to Hela
cells. The significance of the “fetal” binder
is presently unclear. Binding studies were
not performed on the sera of patients in this
study, although serum protein
electro-phoreses
(
agarose gel method)
wereunre-markable. Thus, while alterations in serum
proteins could provide an explanation for
the changes seen, direct data are not
avail-able upon which to base such a conclusion.
It is probable that the reduced levels of
vitamin B,, result from a combination of
factors: insufficient dietary intake of B,,,
limited body stores, and increased demands
related to growth. During the early period
in the hospital, the infants received 200 to
300 ml of a formula containing
approxi-mately 0.73tg of B,, per liter. The initial
daily intake would thus be approximately
0.22g, an amount which is less than the
in-take recommended for normal infants on
ar-tificial feeding, i.e., 0.3tg’4; prematurely
born infttnts may have slightly higher
re-quirements. Adequate dietary B12 intake would be expected only after the institution
of solid foods, particularly meats, which
be-gins several weeks following birth.
Further-more, despite the competitive advantage for
B1, demonstrated by the fetus in utero,”
total body stores at birth are probably
re-duced. For example, fetal liver contains
only one-third the concentration of vitamin
B,, as that found in adult liver,” the major
site for storage of this vitamin. Finally, all
infants in this study were clinically well
with normal growth rates. Rapid cellular
replication and myelinization, requiring
sig-nificant quantities of vitamin B,,, would
lead to a further depletion of vitamin
stores. In the absence of adequate dietary
supplementation, a decrease in serum B,,
levels would be expected.
All infants studied at birth (ten of ten)
had serum and red cell folate levels in
ex-cess of normal adult values. All
demon-strated a fall in serum concentrations with
three reaching serum levels less than 6 ng/
ml. Red cell folate concentrations were
con-sistently above 160 ng/mi. Previous
investi-gators have noted a similar pattern which
was attributed to the combination of low
dietary folate intake and exhaustion of the
high
initial stores derived from the mother.’6Recent studies showing rapid clearance
of folic acid from plasma and diminished
urinary excretion of folic acid in newborns
have suggested an increased demand for
folic acid in the neonatal period and during
the period of early infancy, a demand not
met by dietary foiate.”
From a practical point of view the
de-crease in serum vitamin levels might be
considered “physiologic” in that it occurred
in all infants during the early neonatal
pe-riod with some infants manifesting an
ac-centuation of this trend resulting in
dis-tinctiy low serum concentrations. Because
there did not appear to be any
hematologi-cal or clinical significance to the decreased serum levels, the necessity for supplemental
vitamin therapy is not definite.
Neverthe-less the need for more detailed studies
seems apparent.
REFERENCES
1. Schaffer, A. J.: In Diseases of the Newborn,
ed 2. Philadelphia : W. B. Saunders Co.,
1965, p. 554.
2. Wintrobe, M. M. : In Clinical Hematology, ed 6. Philadelphia : Lea and Febiger, 1967, p. 835.
3. Smith, C. H. : In Blood Diseases of Infancy
and Childhood, ed. 2. St. Louis: C. V.
Mosbv Co., 1966, pp. 196, 206.
4. Shojania, A. NI., and Gross, S. : Folic acid
deficiency and prematurity. J. Pediat., 64:
323, 1964.
5. Gray, 0. P., and Butler, E. B. : Megaloblastic
anaemia in premature infants. Arch. Dis. Child., 40:53, 1965.
6. Ghitis, J., and Canosa, C. : Folate and B12
serum levels in premature infants. With a
note on milk folate. J. Pediat., 67:701,
1965.
7. Herbert, V. : Aseptic addition method for
Lactobacillus casei assay of folate activity
in human sen,m. J. Clin. Path., 19:12,
1966.
8. Hoffbrand, A. V., Newcombe, B. F. A., and
Mollin, D. L. : Method of assay of red cell
ARTICLES 589
as a test for folate deficiency. J. Clin. Path.,
19:17, 1966.
9. Gottlieb, C., Lau, K., Wasserman, L. R., and
Herbert, V. : Rapid charcoal assay for
in-trinsic factor (IF), gastric juice
unsatu-rated B,2 binding capacity, antibody to IF, and serum unsaturated B,2 binding capacity.
Blood, 25:875, 1965.
10. Luhby, A. L., Feldman, R., Marley, J. F.,
Odang, 0., and Cooperman, J. M. : Serum
vitamin B,2 in infancy (Abstract). Fed.
Proc. 20:451, 1961.
11. Boger, W. P., Bayne, G. M., Wright, L. D.,
and Beck, C. D. : Differential serum
vita-mm B12 concentrations in mothers and
in-fants. New Eng. J. Med., 256:1085, 1957.
12. Agunod, M., Yamaguchi, N., Lopez, R., Luhby,
A. L., and Glass, G. B. J.: Correlative study
of hydrochloric acid, pepsin, and intrinsic
factor secretion in newborns and infants.
Amer. J. Dig. Dis., 14:400, 1969.
13. Kumento, A. : The serum binders of vitamin
B2 in newborn infants (Abstract ). Acta
Paediat. Scand., 58:553, 1969.
14. Report of a Joint FAOIWHO Expert Group
on “Requirements of ascorbic acid, vitamin
D, vitamin B,2, folate, and iron.” Food and
Agriculture Organization of the United
Nations, Rome, 1970, p. 40.
15. Rappazzo, M. E., Salmi, H. A., and Hall,
C. A. : The content of vitamin B,2 in adult and foetal tissue : A comparative study. Brit. J. Haemat., 18:425, 1970.
16. Roberts, P. M., Arrowsmith, D. E., Rau,
S. M., and Monk-Jones, M. E. : Folate
status of premature infants. Arch. Dis. Child., 44:637, 1969.
17. Shojania, A. M., and Hornadv, C.: Folate
metabolism in newborns and during early
infancy: II. Clearance of folic acid in
plas-ma and excretion of folic acid in urine by
newborns. Pediat. Res. 4:422, 1970.
. . . THE PASTORAL FALLACY
The pastoral fallacy is a creation of a section
of the profession, and probably arises as a reac-tion, by those no longer able to keep abreast, to the technical complexities of modern medicine. Its
proponents emphasize the distinction between the
patient and his disease, and claim to treat the
whole man, and to regard the patient as a peron.
They stress the frequency and educational
im-portance of the more trivial disorders and their
interrelation with emotional factors. There is an
implication that much of the elaboration of
mod-em investigation and treatment could be dispensed
with, if doctors were trained to acquire wisdom
rather than to accumulate technical knowledge.
Pervaded by an excessive belief in a unique
thera-peutic relation between doctor and patient, they
aim to substitute a pastoral role for technical care,
which is assumed to be necessarily impersonal or
even inhumane. . . . The essential superficiality, and indeed dishonesty, of this attitude is revealed
when one of its advocates is faced with illness in
himself or in his family. The call then is not for the wise father figure, but for the man who knows most about so-and-so.
A. C. DORNHORST
ALASTAIR Hursn
Fallacies in Medical Education