Identification of changes in sleep across pregnancy and the impact on cardiometabolic health and energy intake in women with obesity.

This prospective, observational study investigated changes in sleep and the effect on energy intake, gestational weight gain, and cardiometabolic health across pregnancy in 52 healthy pregnant women with obesity. Habitual sleep was assessed by wrist-worn actigraphy (time spent in bed; TIB, total sleep time; TST, and sleep efficiency) in early (130-156 weeks) and late (350-366) pregnancy. A change to habitual sleep was defined as change of one-half of the standard deviation of TIB and TST across six consecutive nights from early pregnancy. Energy intake and changes in weight, fasting glucose, insulin, and lipids across pregnancy were compared between women who changed sleep. During early pregnancy, TIB was 9:24 ± 0:08 h and varied by 1:37 ± 0:07 h across the six nights. TST and sleep efficiency significantly declined from early to late pregnancy (7:03 ± 0:08 h to 6:28 ± 0:09 h, p < 0.001) and (76 ± 0.1% to 71 ± 0.2%, p < 0.001), respectively. For women who increased TIB (n = 11), fasting glucose decreased (-11.6 ± 4.3%, p < 0.01) across pregnancy and they had a trend towards decreased insulin (-57.8 ± 33.5%; p = 0.09) and HOMA-IR (-72.4 ± 37.3%; p = 0.06) compared to women who decreased TIB (n = 13). Women who increased TIB had a significantly lower daily energy intake across pregnancy (-540 ± 163 kcal; p < 0.01) and tended to have less gestational weight gain (-147 ± 88 g/week; p = 0.10). Changes in TST did not affect plasma markers, energy intake or weight gain. The positive relationship between sleep and cardiometabolic health during pregnancy is explained in part by lower energy intake. We hypothesize lower energy intake is due to a prolonged overnight fast and a decrease in the time available for eating.