Gestational weight gain during pregnancy is the risk factor for Omicron infection: a retrospective case–control study

It remains unclear whether gestational weight gain (GWG) during pregnancy is associated with Omicron infection in pregnant women.

To investigate whether gestational weight gain during pregnancy is associated with an increased risk of Omicron infection.

This is a retrospective case–control study of pregnant women from The Third Affiliated Hospital of Sun Yat-sen University from December 1 to 31, 2022. Pregnant women infected with Omicron were compared to those uninfected using chi-square statistics for categorical variables and t-tests or ANOVA for continuous variables. Multivariable logistic regression, along with subgroup analyses, was used to investigate the association between gestational weight gain during pregnancy and Omicron infection.

Our study included 369 pregnant women who met the eligibility criteria. The proportion of pregnant women in the term, infected and uninfected with Omicron was 113(30.6%) and 256(69.4%). Classified pregnant women according to GWG during pregnancy, GWG during pregnancy above IOM was significantly associated with an increased risk of Omicron infection (P = 0.006). After adjusting for demographic factors and pregnancy complications, this association was particularly notable (OR = 2.55, 95%CI = 1.35–4.85, P = 0.004). Classified pregnant women according to pregestational BMI, in normal-weight pregnant women, GWG during pregnancy above IOM was significantly associated with an increased risk of Omicron infection (P = 0.01). After adjusting for demographic factors and pregnancy complications, this association was particularly notable (OR = 2.56, 95%CI = 1.24–5.31, P = 0.01).

Among women with normal weight, gestational weight gain during pregnancy above IOM was an independent risk factor for Omicron infection.