Study population and setting
This study included 427 pregnant women hospitalized with laboratory-confirmed SARS-CoV-2 infection from March 1, 2020 to April 14, 2020 from the UK Obstetric Surveillance System (UKOSS), which incorporated data from all 194 obstetric units across the UK.
Summary of Main Findings
Slightly more than half (56%) of the pregnant women hospitalized with COVID-19 during the study period were Black or from another ethnic minority group, 41% were ≥35 years old, 34% had underlying comorbidities, and 69% were overweight or obese at first antenatal visit. The median completed gestation at admission was 34 weeks (IQR: 29-38). Pregnant women presented with typical symptoms (e.g. fever, cough, shortness of breath), and 104 (24%) had pneumonia. Overall, 41 (10%) required critical care, and five (1%) died. By the end of the study period, pregnancy was ongoing for 38% of women. Among the remaining 266 with observed pregnancy outcomes, there were 259 live births (60% by cesarean; 73% at term), and seven cases of pregnancy loss or stillbirth. SARS-CoV-2 testing by PCR among 256 infants identified 12 (5%) cases, half of whom tested positive within 12 hours after birth. The incidence of COVID-19 in pregnancy during the six week study period was estimated to be 4.9 per 1000 maternities (95% CI: 4.5-5.4), with higher rates among Black women, women ≥35 years, and women who were overweight or obese.
The inclusion of data from all maternity wards in the UK is a major strength of the study, providing national estimates of COVID-19 hospitalization and outcomes in pregnancy. Pulling from all maternity wards, rather than just a subset, also ensures that the results are more generalizable instead of just being associated with attendance at individual facilities. The use of active COVID-19 surveillance in the context of the existing UKOSS platform likely increased the number of cases included into the study (i.e., case ascertainment). PCR testing for SARS-CoV-2 infection among neonates was also extensive (99% tested).
The severity of disease among the pregnant women in this study was unclear. Severity was also difficult to compare to other studies because the researchers did not use the standard WHO definitions or include data on respiratory rate and blood oxygen levels. Except for hospitalization incidence, the outcomes are descriptive and presented among the overall population, without showing stratification by race and other salient sub-groups. It is unclear whether all pregnant women admitted to the hospital with COVID-19 were linked to the obstetric units; if not, it is possible that researchers missed cases hospitalized earlier in their pregnancy. Like previous studies, most of the study population was in the late second or third trimester of pregnancy, and thus the results do not provide information on the effects of SARS-CoV-2 infection during the first trimester, when fetal organ development is in its early stages.
This study provided representative national data on the incidence and outcomes of hospitalizations for symptomatic COVID-19 among pregnant women in the UK, and is one of the largest with systematic PCR testing among neonates.
This review was posted on: 4 July 2020