Associations of COVID-19 lockdown with gestational length and preterm birth in China.

BACKGROUND: The effects of COVID-19 lockdown measures on maternal and fetal health remain unclear. We examined the associations of COVID-19 lockdown with gestational length and preterm birth (PTB) in a Chinese population. METHODS: We obtained medical records of 595,396 singleton live infants born between 2015 and 2020 in 5 cities in Guangdong Province, South China. The exposed group (N = 101,900) included women who experienced the COVID-19 Level I lockdown (1/23-2/24/2020) during pregnancy, while the unexposed group (N = 493,496) included women who were pregnant during the same calendar months in 2015-2019. Cumulative exposure was calculated based on days exposed to different levels of emergency responses with different weighting. Generalized linear regression models were applied to estimate the associations of lockdown exposure with gestational length and risk of PTB (< 37 weeks). RESULTS: The exposed group had a shorter mean gestational length than the unexposed group (38.66 vs 38.74 weeks: adjusted ß = - 0.06 week [95%CI, - 0.07, - 0.05 week]). The exposed group also had a higher risk of PTB (5.7% vs 5.3%; adjusted OR = 1.08 [95%CI, 1.05, 1.11]). These associations seemed to be stronger when exposure occurred before or during the 23rd gestational week (GW) than during or after the 24th GW. Similarly, higher cumulative lockdown exposure was associated with a shorter gestational length and a higher risk of PTB. CONCLUSIONS: The COVID-19 lockdown measures were associated with a slightly shorter gestational length and a moderately higher risk of PTB. Early and middle pregnancy periods may be a more susceptible exposure window.

Smoking status and maternal weight trajectories during pregnancy and postpartum: Preliminary results from a pilot study.

OBJECTIVE: To preliminarily examine throughout pregnancy and 12 months postpartum: 1) the critical timings of abnormal gestational weight gain (GWG) among quitters and non-quitters; 2) the consequences of abnormal GWG on weight retention during postpartum; 3) the potential difference in GWG by timing of quitting (early vs. late). METHODS: We included 59 pregnant smokers (49 quitters and 10 non-quitters) from two clinical pilot studies. Smoking status and weight were repeatedly measured throughout pregnancy and postpartum. Weight trajectories were analyzed using mixed models with smoking cessation status, pregnancy week or postpartum month, their interaction term, and potential confounders. RESULTS: At enrollment, mothers had a mean BMI of 28.7 (SD, 7.2) and mean age of 30.1 years (SD, 5.8). Both groups had a linear increase in GWG, but quitters had a much higher rate of GWG (0.87 vs. 0.22 pounds/week) than non-quitters throughout pregnancy. Before delivery, 63.3% of quitters and 20.0% of non-quitters had excessive total GWG, while 12.2% of quitters and 60.0% of non-quitters had inadequate total GWG (p-value=0.004). Early quitters (<21 weeks) had a higher risk of excessive GWG (85.0%) than late quitters (≥21 weeks, 36.4%) (p-value=0.026). After delivery, quitters' weight remained stable following a rapid weight loss, whereas non-quitters' weight increased continuously. CONCLUSIONS: Non-quitters have a high risk of inadequate GWG, while quitters, especially early quitters, have a high risk of excessive GWG. The group difference in weight trajectories lasted from conception to postpartum.