Heavy night-time eating during pregnancy may factor in early childbirth

Pregnant women in Singapore who eat heavier at night than during the day appear to have shorter gestation and are at greater odds of delivering preterm, according to a local study.

“The extent to which eating time can influence reproductive health is a new area of research,” the investigators said. “Th[is] study suggests that misalignment of eating time with day–night cycles may be a risk factor for preterm birth.”

A total of 673 pregnant women (mean age, 30.9 years) from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort were included in the analysis. Maternal energy intake data at 26–28 weeks' gestation showed that 105 of these women (15.6 percent) engaged in night-eating, consuming >50 percent of total energy intake from 1900 to 0659 hours. Eighty-three women (12.3 percent) slept for <6 hours nightly.

Delivery occurred before 37 weeks of gestation in 46 women (6.8 percent). The main medical indications for preterm delivery were foetal distress, maternal distress, pre-eclampsia and diabetes.

In multivariable logistic regression models, the odds of preterm birth were twofold higher among women with night-eating pattern than those with higher energy intake during the day (odds ratio [OR], 2.19, 95 percent CI, 1.01–4.72). Furthermore, night-eating was associated with 0.45-weeks shortening of gestation length. [Clin Nutr 2019;doi:10.1016/j.clnu.2019.08.018]

Women with short sleep duration also experienced gestation length shortening (β, –0.33 weeks). However, sleep duration had no significant association with preterm birth (OR, 1.81, 0.76–4.30).

According to the investigators, consuming food during the rest phase of the body (ie, night) may induce circadian misalignment and melatonin secretion suppression, which could eventually lead to dysregulation of uterine contractility and birth timing. [Proc Nutr Soc 2018;77:199-215; Obstet Gynecol Int 2015;2015:825802; Best Pract Res Clin Obstet Gynaecol 2018;52:60-67]

The effect estimates of short sleep duration, on the other hand, could be too small to translate into a significant increase in preterm birth risk, they explained.

“Although reduction in gestation length was modest and late preterm (34–36 weeks' gestation) accounted for 91 percent of preterm birth cases in this study, the child health consequences are of clinical and public health importance,” they continued.

Several studies provide evidence of elevated risks of infant morbidity and childhood disabilities for infants with modest decrease in gestation across a broad spectrum, regardless of being born at term or preterm. Furthermore, late preterm birth has been associated with a number of components of the metabolic syndrome and cardiovascular disease in adult life. [Front Psychol 2011;2:1; Semin Fetal Neonatal Med 2012;17:120-125; J Pediatr 2019;210:69-80]

“Our current findings thus call for increased clinical attention to maternal time of food intake, [as well as] the study of potential intervention strategies based on circadian eating approach which are feasible and culturally appropriate, with the aim of reducing risk of preterm birth,” the investigators said, adding that observations for nightly sleep deprivation in relation to gestation length and early delivery warrant further confirmation.