Shift work and pregnancy: night light, baby not right

Circadian gene Rev-erbα influenced by sleep conduces to pregnancy by promoting endometrial decidualization via IL-6-PR-C/EBPβ axis

BACKGROUND

Sleep disturbance can cause adverse pregnancy outcomes by changing circadian gene expression. The potential mechanisms remain unclear. Decidualization is critical for the establishment and maintenance of normal pregnancy, which can be regulated by circadian genes. Whether Rev-erbα, a critical circadian gene, affects early pregnancy outcome by regulating decidualization needs to be explored.

METHODS

QPCR, western blot and artificial decidualization mouse model were used to confirm the effect of sleep disturbance on Rev-erbα expression and decidualization. The regulatory mechanism of Rev-erbα on decidualization was assessed using QPCR, western blot, RNA-Seq, and Chip-PCR. Finally, sleep disturbance mouse model was used to investigate the effect of therapeutic methods targeting Rev-erbα and interleukin 6 (IL-6) on improving adverse pregnancy outcomes induced by sleep disturbance.

RESULTS

Dysregulation of circadian rhythm due to sleep disturbance displayed abnormal expression profile of circadian genes in uterine including decreased level of Rev-erbα, accompanied by defective decidualization. Rev-erbα could regulate decidualization by directly repressing IL-6, which reduced the expression of CCAAT/enhancer-binding protein β (C/EBPβ) and its target insulin-like growth factor binding protein 1 (IGFBP1), the marker of decidualization, by inhibiting progesterone receptors (PR) expression. Moreover, deficient decidualization, higher abortion rate and lower implantation number were exhibited in the mouse models with sleep disturbance compared with those in normal mouse. Pharmacological activation of Rev-erbα or neutralization of IL-6 alleviated the adverse effect of sleep disturbance on pregnancy outcomes.

CONCLUSIONS

Taken together, Rev-erbα regulated decidualization via IL-6-PR-C/EBPβ axis and might be a connector between sleep and pregnancy outcome. Therapies targeting Rev-erbα and IL-6 might help improving adverse pregnancy outcomes induced by sleep disturbance.

Maternal night-time eating and sleep duration in relation to length of gestation and preterm birth

BACKGROUND & AIMS

Maternal metabolic disturbance arising from inappropriate meal timing or sleep deprivation may disrupt circadian rhythm, potentially inducing pregnancy complications. We examined the associations of maternal night-time eating and sleep duration during pregnancy with gestation length and preterm birth.

METHODS

We studied 673 pregnant women from the Growing Up in Singapore Towards healthy Outcomes (GUSTO) cohort. Maternal energy intake by time of day and nightly sleep duration were assessed at 26-28 weeks' gestation. Based on 24-h dietary recall, night-eating was defined as consuming >50% of total energy intake from 1900 to 0659 h. Short sleep duration was defined as <6 h night sleep. Night-eating and short sleep were simultaneously analyzed to examine for associations with a) gestation length using multiple linear regression, and b) preterm birth (<37 weeks' gestation) using logistic regression.

RESULTS

Overall, 15.6% women engaged in night-eating, 12.3% had short sleep and 6.8% delivered preterm. Adjusting for confounding factors, night-eating was associated with 0.45 weeks shortening of gestation length (95% CI -0.75, -0.16) and 2.19-fold higher odds of delivering preterm (1.01, 4.72). Short sleep was associated with 0.33 weeks shortening of gestation length (-0.66, -0.01), but its association with preterm birth did not reach statistical significance (1.81; 0.76, 4.30).

CONCLUSIONS

During pregnancy, women with higher energy consumption at night than during the day had shorter gestation and greater likelihood of delivering preterm. Misalignment of eating time with day-night cycles may be a contributing factor to preterm birth. This points to a potential target for intervention to reduce the risk of preterm birth. Observations for nightly sleep deprivation in relation to gestation length and PTB warrant further confirmation.