Maternal Habitual Midday Napping Duration and Frequency are Associated with High Birthweight

Physical behaviours during pregnancy may alter the association of maternal insulin sensitivity with neonatal adiposity: a prospective pre-birth cohort of mother-child pairs

BACKGROUND

Lower maternal insulin sensitivity during pregnancy is associated with greater fetal adiposity. Physical activity can improve insulin sensitivity, but it is not known if physical behaviours influence the known association of maternal insulin sensitivity with offspring adiposity. This study aimed to investigate the moderating impact of physical behaviours on this association.

METHODS

Pregnant women (n = 812) from the Gen3G cohort were recruited during the first trimester of pregnancy and followed until delivery. At the first (V1) and second trimester (V2) hospital visits, Gen3G staff measured anthropometry, and participants reported sleep duration as well as leisure physical activity and sedentary behaviour via lifestyle questionnaires. We used plasma glucose and insulin values from the 75 g oral glucose tolerance test at V2 to calculate insulin sensitivity using the Matsuda index. We recorded birthweight from electronic medical records. Among a subset of neonates (n = 265), trained research staff measured skinfold thickness using a calibrated skinfold caliper following standardized protocols to estimate neonatal adiposity. Linear regression analyses assessed the association of insulin sensitivity with birthweight z-score and sum of neonatal skinfold thickness, adjusting for maternal age, race/ethnicity, gravidity, smoking, with and without adjustment for maternal body mass index at V1. We evaluated moderation by physical activity, sedentary behaviour, or nighttime sleep duration using interaction terms and stratified analyses for the association of maternal insulin sensitivity with offspring birthweight and with offspring adiposity.

RESULTS

Lower Matsuda index was associated with higher birthweight z-score (ß±SE= -0.180 ± 0.056, p = 0.001) and with higher sum of skinfold thickness (neonatal adiposity) (ß±SE=-0.877 ± 0.383, p = 0.02) in fully adjusted models. The association between Matsuda index and sum of skinfold thickness was weaker in women with higher levels of physical activity at V2 ([high ≥ 1.26 kcal/kg/day] ß±SE=-0.15 ± 0.65) compared to women with lower levels [low < 1.26 kcal/kg/day] ß±SE=-1.36 ± 0.51, P-interaction = 0.01). We also observed potential interactions of sleep and sedentary behaviour at V2 with Matsuda index for the association with birthweight z-score. We did not observe effect modification by levels of physical behaviours assessed at V1.

CONCLUSION

The association between lower insulin sensitivity and higher neonatal adiposity was attenuated in women with higher physical activity levels in the second trimester, independent of maternal body mass index.

Sleep and physical activity from before conception to the end of pregnancy in healthy women: a longitudinal actigraphy study

BACKGROUND

Sleep and physical activity changes are common in pregnancy, but longitudinal data starting before conception are scarce. Our aim was to determine the changes of the daily total sleep time (TST) and physical activity duration (PAD) from before conception to end of pregnancies in respect of pregestational maternal factors.

METHODS

This longitudinal observational study formed part of the CONIMPREG research project and recruited healthy women planning to become pregnant. Sleep and physical activity were recorded around-the-clock for ≥4 days via actigraphy before conception and during each trimester of pregnancy. Data were adjusted according to pregestational maternal body composition, parity and age.

RESULTS

Among 123 women with eligible data, the unadjusted mean (95% confidence interval) TST increased from 415.3 min (405.5-425.2 min) before conception to 458.0 min (445.4-470.6 min) in the 1st trimester, remaining high through the 2nd and 3rd trimesters. Variation was substantial before conception (±2SD range: 307-523 min). The unadjusted mean PAD before conception was 363.7 min (±2SD range: 120-608 min), decreasing sharply to 262.1 min in the first trimester and more gradually thereafter. Vigorous and moderate activity decreased more than light activity. TST and PAD were significantly associated with age, parity, and pregestational body fat percentage; lean body mass was negatively correlated with TST. Results were generally unaffected by seasonal variations.

CONCLUSION

Marked variations were found in pregestational TST and PAD. Healthy women slept ≥30 min longer during pregnancy, while PAD decreased by ≥ 90 min in early pregnancy and continued to decrease thereafter.