Subjects
Pregnant NW (BMI 18.5–24.9 kg/m2) and OB (BMI ≥30
kg/m2), aged 20–45 years, were recruited from six
antenatal health units in the Gothenburg area as part of the Pregnancy
Obesity Nutrition and Child Health (PONCH) study, as
described22. Exclusion
criteria were non-European descent, diabetes mellitus (type 1, type 2,
or gestational) or other chronic diseases, pregnancy-related
complications, use of tobacco or neuroleptic drugs, and vegetarianism or
veganism. The women came to the Sahlgrenska University Hospital for
study visits once each trimester (weeks 8–12, 24–26, and 35–37; T1,
T2, and T3, respectively) during pregnancy and at 6, 12, and 18 months
(± 10 days) after pregnancy. Gestational age at study visits were on
average 81 ± 8 days at T1, 175 ± 8 days at T2 and 253 ± 7 days at T3,
and did not differ between NW and OB (p >0.4).
GDF15 was measured in a subset of the total 132 NW and 50 OB that
enlisted in PONCH. Subjects for the present study were selected from
those who had complete serum samples and body composition measurements
from T1 or T2 until 18 months after pregnancy. Of 71 NW who had complete
visits, 38 were randomly selected. Selected NW did not differ from
non-selected NW in BMI, body composition, or homeostatic model
assessment of insulin resistance (HOMA-IR). All OB who had the maximal
number of visits were selected. The number of subjects for NW after
pregnancy was matched with OB (n=30 after pregnancy). A few subjects
were lacking in T2 samples. This resulted in differences in the numbers
for visits at T1 (38 NW and 28 OB), T2 (30 NW and 29 OB), and T3 (38 NW
and 35 OB) and at 6 months (30 NW and 30 OB), 12 months (30 NW and 24
OB), and 18 months (30 NW and 11 OB) postpartum. The reasons given for
postpartum drop-outs in the OB group were lack of time, moving to a
different part of Sweden, or a new pregnancy.