Background and aim : Gesta�onal diabetes mellitus (GDM) affects 10.9% of pregnant women in
Switzerland and 14% of pregnancies worldwide. GDM can lead to complica�ons, such as prenatal and
perinatal risk for the mother and her child as well as long term risks for both of them. There are
controversial results concerning the impact of maternal fitness on child outcomes at birth. But there is
a lack of evidence regarding a poten�al longer-term impact. The aims of this study are to describe
maternal fitness in mother with GDM and their changes between pregnancy and the postpartum and
to explore the rela�onship between maternal fitness during pregnancy and infant outcomes at birth,
6-8 weeks and 1 year of age (weight, BMI, fat mass, fat free mass and sum of skinfolds).
Methods : This study is a substudy of My SweetHeart Trial where 211 women with GDM were recruited
between 2016 and 2020 and 1:1 randomised to a control and interven�on group. The study
par�cipa�on involved 4 visits for the mother and/or her child at the following �me points: at 24-32
weeks of pregnancy (baseline visit), at birth, at 6-8 weeks and at 1 year postpartum. We focused on
the control group (N = 106) and considered maternal fitness at the baseline visit and 1 year postpartum
and offspring outcomes at birth, 6-8 weeks and 1 year of age. Measures for maternal fitness included
VO2max and hand grip strength and offspring outcomes included weight, BMI, fat mass, fat free mass
and sum of skinfolds.
Results : Weight and BMI of the mother significantly decreased between the baseline visit and 1 year
postpartum, with -7.0 kg +/- 5.5 and -2.6 kg/m2 +/- 2.0, respec�vely, while VO2max and hand grip
strength of the mother showed no significant difference between the first and the last visit (p = 0.69
and p = 0.19 respec�vely). The hand grip strength of the mother at the baseline visit was posi�vely
related to the sum of skinfolds of the offspring at age 6-8 weeks (β= 0.56 [0.18, 0.93], t= 2.96, p= 0.004).
The maternal VO2max at baseline visit was also posi�vely related to the sum of skinfolds of the
offspring at age 6-8 weeks (β = 0.27 [0.008, 0.54], t = 2.05, p= 0.04). There was a tendency for a posi�ve
associa�on of maternal VO2max in pregnancy and fat free mass of the offspring at age 1 (p= 0.051).
We didn’t find other significant associa�ons between maternal fitness and infant outcomes.
Conclusion: In conclusion, maternal fitness of mother with GDM did not significantly change between
the beginning of the third trimester and 1 year postpartum. Maternal fitness at the onset of third
trimester could have an impact on the body fat of her child at age 6-8 weeks and poten�ally on fat-
free mass at age 1 year. This should be confirmed and retested in further studies, ideally using more
exact measures such as DXA.
What this study adds :
This study inves�gated the rela�onship between maternal fitness in women with GDM and her infant’s
body composi�on up to 1 year of age. It showed a longer-term perspec�ve about the rela�onship
between maternal fitness and infant outcomes in a very specific popula�on at high metabolic risk.