| dc.description.abstract | Background: The focus on riboflavin and vitamin C inthis study emanated from their
important physiological functions. Reported studies of the association between maternal
dietary intake of riboflavin and vitamin C, and birth anthropometry show conflicting results
and it is not known whether their intakes influence intrauterine growth. Gender-specific
differences in foetal response to nutritional and environmental factors during pregnancy have
been suggested.
Objectives:To examine whether maternal dietary intake of riboflavin and vitamin C around
17-20 weeks of gestation is associated with foetal growth and birth weight, and if the
association is gender specific.
Design:Prospective cohort study conducted 1986-1988 and designed to examine factors
related to intrauterine growth.
Setting:Routine pregnancy care, special study visits, and University hospital in Bergen and
Trondheim with surroundings.
Participants: 872 women of Caucasian origin and their second or third singleton offspring.
Main outcome measures:Weight deviation (in per cent) from normal weight for the
estimated gestational age based on ultrasound measures around 25, 33 and 37 weeks of
gestation, and birth weight.
Methods: Information on maternal riboflavin and vitamin C intake was obtained from 3-d
dietary records. Before statistical analysisthe intakes were categorized by dividing the
frequency distribution into tertiles. Cross-sectional, covariate adjusted multiple linear
regression analyses were performed by vitamin and foetal gender. The following covariates
were considered: total energy intake, maternalage at study entry, pre-pregnancy body mass
index, maternal smoking during pregnancy, highest completed education, previous number of
births, and serum ferritin. In addition, for female offspring the analysis regarding maternal
riboflavin intake and birth weight was also adjusted for gestational age at delivery.
Results: We observed no association between maternalriboflavin intake and estimated foetal
weight deviation during the second or third trimester. Unlike univariate analysis, multivariate
analysis showed a borderline significant inverse association between maternal riboflavin
intake and birth weight, - 56 g (95% confidence interval -77 to 4) for female infants. There
was no such association for males. Maternal vitamin C intake was unrelated to estimated
weight deviation at 25 and 33 weeks of gestation in both genders. At 37 weeks of gestation
the association was borderline significant for male fetuses only, 1.1% (95% confidence
interval -0.1 to 2.3). One unit (tertile) change in vitamin C intake was associated with a 71 g
(95% confidence interval 9 to 132) increase inbirth weight in female infants. Again, no
association was observed among males. Conclusions
We found a borderline significant inverse association between maternal riboflavin intake and
birth weight for female, but not for male infants. For both genders there was no association
with the estimated foetal weight deviation. There was also a significant positive association
between maternal intake of vitamin C and birth weight for female infants and a borderline
significant positive association with estimated foetalweight deviation for male foetuses in late
third trimester (gestational week 37). Our findings should be interpreted cautiously. Besides
some concern about the validity ofdietary intake data, the choice of statistical methods could
be questioned. Further, the borderline significant and significant findings may be biased by
uncontrolled confounding, or be related to other factors than maternal riboflavin or vitamin C
intake per se. Therefore, further studies are needed to elucidate the potential role of riboflavin
and vitamin C in foetal growth. Studies should focus on intrauterine growth as a longitudinal
process in addition to a continued focus on possible gender-specific differences, and
preferably by adding biomarkersof different nutrients. Also, warranted are studies of overall
dietary patterns or diet quality, for instance in combination with important environmental
exposures and lifestyle factors,and their association with the outcomes under study. To our
knowledge, this is the first study that has combined data on maternal vitamin intake, foetal
growth and birth weight. Hence, it is also the first study to indicate a possible gender specific
influence of riboflavin and vitamin C intake on estimated foetal weight deviation/birth
weight. | nb_NO |
