key: cord-0706652-ul9pga8t
authors: Butler, Emily Ana; Cohen, Eyal; Berger, Howard; Ray, Joel G.
title: Change in Pre-Pregnancy Body Mass Index in Relation to COVID-19 Pandemic
date: 2021-11-05
journal: J Obstet Gynaecol Can
DOI: 10.1016/j.jogc.2021.09.014
sha: e130b4b3480584a96e0ea68edc699e5d2ecee0b4
doc_id: 706652
cord_uid: ul9pga8t

nan

Change in Pre-Pregnancy Body Mass Index in Relation to COVID-19 Pandemic D uring the coronavirus disease 2019 pandemic, daily physical activity has declined among many individuals. 1 Thus, even at a constant caloric intake, one might expect a rise in body mass index (BMI) during the COVID-19 era. In the short term, this may be of concern for pregnant women. Maternal pre-pregnancy obesity is a known predictor of adverse pregnancy outcomes, such as preeclampsia. 2 This study evaluated whether maternal pre-pregnancy BMI changed from the era before the COVID-19 pandemic to that during the pandemic.

We used existing, deidentified pregnancy and birth data at St. Michael's Hospital in Toronto, Ontario-a level II inner-city hospital with about 2500 births annually. All singleton livebirths were included from January 1, 2017 , to June 30, 2021 , with corresponding pre-pregnancy BMI values from March 22, 2016 , to November 20, 2020 . We excluded women whose pre-pregnancy height and weight were both missing or whose BMI was implausibly reported as <15 kg/m 2 or >60 kg/m 2 .

Mean maternal pre-pregnancy BMI was aggregated by 1-month time intervals. A segmented regression time series was established, setting the interruption to March 15, 2020 (the onset of the pandemic in Ontario) using a slope function. A washout period, from March 15 to May 15, 2020, Figure. Monthly mean maternal pre-pregnancy body mass index among 9703 women with a singleton livebirth before (blue circles) and during (orange squares) the SARS-CoV-2 pandemic (vertical dashes line). A washout period from March to May 2020 is included in the segmented regression time series model (1).

SARS-CoV-2: severe acute respiratory syndrome coronavirus-2.

was incorporated in the model to account for the period during which the COVID-19 pandemic emerged in Ontario and lockdown protocols were gradually introduced. The mean (95% confidence interval [CI]) change in maternal BMI was calculated from before to during the COVID-19 era. Logistic regression generated an odds ratio for pre-pregnancy obesity (i.e., BMI ≥30 kg/m 2 ) during versus before the pandemic. Potential confounders, such as maternal age and parity, were included in all of the aforementioned analyses.

A total of 9112 women were included pre-pandemic and 591 during the pandemic. The mean (standard deviation) age was 33.0 (4.8) years and median (interquartile ratio) parity was 0 (1) for both groups.

The mean (standard deviation) BMI was 24.9 (6.5) kg/m 2 pre-pandemic and 25.4 (6.2) kg/m 2 during the pandemic (Figure) . This corresponded to an unadjusted mean difference of 0.5 kg/m 2 (95% CI 0.0−1.1) and an adjusted mean difference of 0.5 kg/m 2 (95% CI 0.0−1.0). Segmented regression showed a steeper slope for pre-pregnancy BMI during compared with before the pandemic, with a P-value of 0.06 for the associated effect of the interruption of the COVID-19 pandemic on pre-pregnancy BMI (Figure) .

Pre-pregnancy obesity occurred in 1255 women (13.8%) prepandemic and 103 women (17.4%) during the pandemic, with an unadjusted and adjusted odds ratio of 1.3 (95% CI 1.1−1.7). An incremental rise in maternal pre-pregnancy BMI was observed after the emergence of the COVID-19 pandemic, along with an increased rate of obesity.

This single-centre study was limited to singleton livebirths, with pre-pregnancy BMI collected nearer to the beginning of the pandemic. Physical activity, dietary intake, and cigarette smoking were not accounted for, nor was any unrealized preferential tendency among women with a higher BMI to conceive during the pandemic.

Others recently observed a rise in BMI among children and adolescents related to the COVID-19 pandemic. 3 Certainly, if the currently observed finding of a rise in prepregnancy BMI is correct and persistent, adverse maternal and perinatal events related to maternal obesity would be expected to emerge. Accordingly, large population-based studies might evaluate trends in pre-pregnancy BMI and pregnancy weight gain related to the COVID-19 pandemic, alongside ensuing adverse outcomes for mother and newborn.

Reduced level of physical activity during COVID-19 pandemic is associated with depression and anxiety levels: an internet-based survey

Maternal body mass index and the risk of preeclampsia: a systematic overview

Changes in body mass index among children and adolescents during the COVID-19 pandemic

The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada