GDF15 levels during and after pregnancy
In NW, serum GDF15 increased 40-fold in T1 to 200-fold in T3 compared
with nonpregnant values (i.e. after pregnancy), as shown in Fig 1A. OB
showed a similar trend although the increases were slightly lower in T2
and T3 than in NW. After the initial postpartum decrease, GDF15 did not
significantly change between 6, 12, and 18 months in either group. GDF15
was generally higher in OB than in NW after pregnancy, but the
difference was significant only at 18 months.
In line with the differences in GDF15 levels between the two groups
during pregnancy, GDF15 levels correlated negatively with body weight
and BMI at T2 (R= –0.385, p = 0.003 and R= –0.336, p =
0.009, respectively) and T3 (R= –0.344, p = 0.003 and R= –0.289,p = 0.013, respectively). In analyses of body composition, GDF15
correlated negatively with FFM (but not FM) in NW at both T1 (R=
–0.433, p = 0.007) and T3 (R= –0.336, p = 0.042). However,
after adjustment for maternal BMI, only the negative correlation between
GDF15 and FFM at T3 remained significant (Fig. 1B). When analyzing the
BMI groups separately, GDF15 correlated negatively with FFM (but not FM)
in NW at both T1 and T3 (R=-0.433, P=0.007 at T1 and R=-0.336,P =0.042 at T3). In the OB group, GDF15 during pregnancy did not
correlate significantly with weight, BMI, or body composition, although
the correlation between GDF15 and FFM at T2 narrowly missed significance
(p = 0.051). After pregnancy, GDF15 correlated positively with FM
at 18 months, but not after adjustment for BMI (Fig. 1C).
GDF15 levels were not consistently associated with changes in weight or
body composition, apart from a negative association between early GDF15
change (T1 to T2) and gestational FM gain (T1 to T3) in NW (R= –0.382,p = 0.037).
In analysis by fetal sex, GDF15 at T1 was significantly higher in women
carrying a female fetus than in those carrying a male fetus (Fig. 1 D).
The difference remained significant after adjustment for maternal BMI.
When analyzing the relationship between GDF15 and nausea, there was a
trend for lower GDF15 at T1 in women not reporting nausea compared to
those that did (12046±4298 ng/L vs 13893±5081 ng/L, respectively,p =0.12). Dividing GDF15 at T1 into quarters, the women with the
lowest quarter of GDF15 reported lower incidence of nausea compared to
the rest (33% vs 64%, respectively, p=0.04). This difference remained
significant after BMI adjustment (p =0.04), but was
non-significant after adjustment for fetal sex (p =0.16).