Results
In the full cohort (Table 1-A), the mean birthweight of infants of
mothers reporting severe anxiety symptoms in the 17thgestational week was 85.3 grams lower than that of infants born to
mothers with very light anxiety symptoms or none at all. Similarly, the
mean birthweight of infants born to mothers reporting severe anxiety
symptoms in the 30th gestational week was 94 grams
lower than that of infants not exposed to high levels of maternal
anxiety. The mean gestational age between light and severe maternal
anxiety differed by two days for those reporting maternal anxiety in the
17th gestational week. Between light and severe
anxiety symptoms reported in the 30th gestational
week, the mean gestational age decreased by three days.
Among the 25,058 siblings (see Table 1-B), a mean birthweight difference
between infants born to mothers reporting light anxiety symptoms and
infants born to mothers reporting severe anxiety symptoms was also
found. However, for the sibling subsample, only a 53.1-gram difference
in mean birthweight was recorded for infants exposed to light anxiety or
none at all, as reported in the 17th gestational week.
Mean birthweight for infants exposed to severe compared to light or no
maternal anxiety, as reported in the 30th gestational
week, differed by 148.3 grams. Mean gestational age decreased by two
days between infants born to mothers reporting severe symptoms and
infants born to mothers reporting light symptoms in the
17th gestational week; however, this difference was
five days for those reporting symptoms in the 30thgestational week.
Differences in anxiety levels between the two pregnancies were also
examined. Of mothers participating twice, a sample of 1,502 mothers
(17%) experienced more anxiety during their first pregnancy than during
their second pregnancy, while 2,756 mothers (9%) had the opposite
experience. The rest of the mothers (74%) experienced the same anxiety
levels during their first and second pregnancies. The mean difference
between maternal anxiety during first and second pregnancies was small
(meandiff = 0.05).