Preeclampsia and COVID-19: results from the INTERCOVID prospective longitudinal study.

BACKGROUND: It is unclear whether the suggested link between COVID-19 during pregnancy and preeclampsia is an independent association or if these are caused by common risk factors. OBJECTIVE: This study aimed to quantify any independent association between COVID-19 during pregnancy and preeclampsia and to determine the effect of these variables on maternal and neonatal morbidity and mortality. STUDY DESIGN: This was a large, longitudinal, prospective, unmatched diagnosed and not-diagnosed observational study assessing the effect of COVID-19 during pregnancy on mothers and neonates. Two consecutive not-diagnosed women were concomitantly enrolled immediately after each diagnosed woman was identified, at any stage during pregnancy or delivery, and at the same level of care to minimize bias. Women and neonates were followed until hospital discharge using the standardized INTERGROWTH-21st protocols and electronic data management system. A total of 43 institutions in 18 countries contributed to the study sample. The independent association between the 2 entities was quantified with the risk factors known to be associated with preeclampsia analyzed in each group. The outcomes were compared among women with COVID-19 alone, preeclampsia alone, both conditions, and those without either of the 2 conditions. RESULTS: We enrolled 2184 pregnant women; of these, 725 (33.2%) were enrolled in the COVID-19 diagnosed and 1459 (66.8%) in the COVID-19 not-diagnosed groups. Of these women, 123 had preeclampsia of which 59 of 725 (8.1%) were in the COVID-19 diagnosed group and 64 of 1459 (4.4%) were in the not-diagnosed group (risk ratio, 1.86; 95% confidence interval, 1.32-2.61). After adjustment for sociodemographic factors and conditions associated with both COVID-19 and preeclampsia, the risk ratio for preeclampsia remained significant among all women (risk ratio, 1.77; 95% confidence interval, 1.25-2.52) and nulliparous women specifically (risk ratio, 1.89; 95% confidence interval, 1.17-3.05). There was a trend but no statistical significance among parous women (risk ratio, 1.64; 95% confidence interval, 0.99-2.73). The risk ratio for preterm birth for all women diagnosed with COVID-19 and preeclampsia was 4.05 (95% confidence interval, 2.99-5.49) and 6.26 (95% confidence interval, 4.35-9.00) for nulliparous women. Compared with women with neither condition diagnosed, the composite adverse perinatal outcome showed a stepwise increase in the risk ratio for COVID-19 without preeclampsia, preeclampsia without COVID-19, and COVID-19 with preeclampsia (risk ratio, 2.16; 95% confidence interval, 1.63-2.86; risk ratio, 2.53; 95% confidence interval, 1.44-4.45; and risk ratio, 2.84; 95% confidence interval, 1.67-4.82, respectively). Similar findings were found for the composite adverse maternal outcome with risk ratios of 1.76 (95% confidence interval, 1.32-2.35), 2.07 (95% confidence interval, 1.20-3.57), and 2.77 (95% confidence interval, 1.66-4.63). The association between COVID-19 and gestational hypertension and the direction of the effects on preterm birth and adverse perinatal and maternal outcomes, were similar to preeclampsia, but confined to nulliparous women with lower risk ratios. CONCLUSION: COVID-19 during pregnancy is strongly associated with preeclampsia, especially among nulliparous women. This association is independent of any risk factors and preexisting conditions. COVID-19 severity does not seem to be a factor in this association. Both conditions are associated independently of and in an additive fashion with preterm birth, severe perinatal morbidity and mortality, and adverse maternal outcomes. Women with preeclampsia should be considered a particularly vulnerable group with regard to the risks posed by COVID-19

Diabetes mellitus, maternal adiposity, and insulin-dependent gestational diabetes are associated with Covid-19 in pregnancy: The INTERCOVID Study.

Background: Among non-pregnant individuals, diabetes mellitus (DM) and high body mass index (BMI) increase the risk of Covid-19 and its severity. Objective: To determine whether DM and high BMI are risk factors for Covid-19 in pregnancy and whether gestational diabetes mellitus (GDM) is also associated with covid-19 diagnosis. Study design: INTERCOVID was a multinational study, conducted between March 2020 and February 2021 in 43 institutions from 18 countries, enrolling 2184 pregnant women ≥18 years; 2071 were included in these analyses. For each woman diagnosed with Covid-19, two non-diagnosed women delivering or initiating antenatal care at the same institution were also enrolled. Main exposures were pre-existing DM or high BMI (overweight/obesity defined as ≥25 kg/m2), and GDM in pregnancy. Main outcome was a confirmed diagnosis of Covid-19 based on an RT-PCR test, antigen test, antibody test, radiological pulmonary findings, or ≥2 predefined Covid-19 symptoms at any time during pregnancy or delivery. Relationships of exposures and Covid-19 diagnosis were assessed using generalized linear models with a Poisson distribution and log link function, with robust standard errors to account for model misspecification. We also conducted sensitivity analyses: 1) restricted to those with an RT-PCR or antigen test in the last week of pregnancy; 2) restricted to those with an RT-PCR or antigen test during the entire pregnancy; 3) generating values for missing data using multiple imputation; and 4) analyses controlling for month of enrollment. In addition, among those who were diagnosed with Covid-19, we examined whether having GDM, DM, or high BMI, increased risk for having symptomatic vs. asymptomatic Covid-19. Results: Covid-19 was associated with preexisting DM (RR=1.94, 95% CI=1.55, 2.42), overweight/obesity (RR=1.20; 95% CI=1.06, 1.37), and GDM (RR=1.21; 95% CI=0.99, 1.46). The GDM association was specifically among women requiring insulin, whether they were of normal-weight (RR=1.79, 95% CI=1.06, 3.01) or overweight/obese (RR=1.77, 95% CI=1.28, 2.45). A somewhat stronger association with Covid-19 diagnosis was observed among women with pre-existing DM, whether they were of normal weight (RR=1.93, 95% CI=1.18, 3.17) or overweight/obese (RR=2.32, 95% CI=1.82, 2.97). When the sample was restricted to those with a RT-PCR or antigen test in the week before delivery or during the entire pregnancy, including missing variables using imputation, or controlling for month of enrollment, the observed associations were comparable. Conclusion: DM and overweight/obesity are risk factors for Covid-19 diagnosis in pregnancy, and insulin-dependent GDM is also associated with the disease. It is therefore essential that those women with these co-morbidities are vaccinated