Impact of Severe Acute Respiratory Syndrome Coronavirus 2 Infection on Pregnancy Outcomes: A Population-based Study

Abstract

Background A population-based study to describe the impact of SARS-CoV-2 infection on pregnancy outcomes. Methods Prospective, population-based study including pregnant women consecutively attended at first/second trimester or at delivery at three hospitals in Barcelona, Spain. SARS-CoV-2 antibodies (IgG and IgM/IgA) were measured in all participants and nasopharyngeal RT-PCR was performed at delivery. The primary outcome was a composite of pregnancy complications in SARS-CoV-2 positive versus negative women: miscarriage, preeclampsia, preterm delivery, perinatal death, small-for-gestational age, neonatal admission. Secondary outcomes were components of the primary outcome plus abnormal fetal growth, malformation, intrapartum fetal distress. Outcomes were also compared between positive symptomatic and positive asymptomatic SARS-CoV-2 women. Results Of 2,225 pregnant women, 317 (14.2%) were positive for SARS-CoV-2 antibodies (n=314, 99.1%) and/or RT-PCR (n=36, 11.4%). Among positive women, 217 (68.5%) were asymptomatic, 93 (29.3%) had mild COVID-19 and 7 (2.2%) pneumonia, of which 3 required intensive care unit admission. In women with and without SARS-CoV-2 infection, the primary outcome occurred in 43 (13.6%) and 268 (14%), respectively [risk difference -0.4%, (95% CI: -4.1% to 4.1)]. As compared with non-infected women, women with symptomatic COVID-19 had increased rates of preterm delivery (7.2% vs. 16.9%, p=0.003) and intrapartum fetal distress (9.1% vs. 19.2%, p=0.004), while asymptomatic women had similar rates to non-infected cases. Among 143 fetuses from infected mothers, none had anti-SARS-CoV-2 IgM/IgA in cord blood. Conclusions The overall rate of pregnancy complications in women with SARS-CoV-2 infection was similar to non-infected women. However, symptomatic COVID-19 was associated with modest increases in preterm delivery and intrapartum fetal distress.

Maternal-Fetal Immune Responses in Pregnant Women Infected with SARS-CoV-2

“…First, we showed that pregnant women with SARS-CoV-2 infection had elevated levels of IgM and IgG in the peripheral circulation, whereas only IgG was detectable in the cord blood of their neonates, suggesting that acute fetal infection did not occur. This finding is consistent with several reports showing that IgM is undetected in the cord blood of neonates born to women with SARS-CoV-2 infection 29,42,43 . However, few studies have demonstrated that both IgM and IgG are detectable in a small fraction of neonates born to women diagnosed with COVID-19 16,24,30 .…”

Immunological and physiopathological approach of COVID-19 in pregnancy

“…A possible overestimation of the risk magnitude of obstetric complications in COVID-19 pregnancies could be partially related to the bias and the relative low level of evidence of first case reports and case series, published by a stressed scientific community, committed to publish clear data to provide knowledge to approach the overwhelming outbreak period of the pandemic. Since then, much data regarding the impact of COVID-19 in pregnancy has been accumulated [58,[65][66][67]. To date, data available about the consequences of COVID-19 in pregnancy outcomes state that preterm delivery and fetal distress are the main adverse outcomes observed in symptomatic COVID-19 pregnancies in the third trimester and at delivery [59,[65][66][67].…”

“…Since then, much data regarding the impact of COVID-19 in pregnancy has been accumulated [58,[65][66][67]. To date, data available about the consequences of COVID-19 in pregnancy outcomes state that preterm delivery and fetal distress are the main adverse outcomes observed in symptomatic COVID-19 pregnancies in the third trimester and at delivery [59,[65][66][67]. The effects of SARS-CoV-2 in the first and second trimesters deserve specific studies to elucidate the controbution of the infection in complications such miscarriage, preeclampsia or IUGR showing variable and inconclusive incidence among published studies [65,[67][68][69][70][71].…”

“…During the period from the third trimester to delivery, COVID-19 leads to an increased incidence of premature ropture of membranes, fetal distress and preterm labour [67,76]. The higher incidence of these complications might be due both the need for reduce the mechanical limitation of thoracic expansion, and to improve maternal oxygenation, as well as the inflammatory response of the maternal multiorganic disease [56,57,65,67].…”

“…A quite low mortality rate has been reported since the COVID-19 outbreak [56,65,67,105,106]. Along with specific case series of maternal deaths [107,108], a systematic review on maternal mortality summarizes that the acute respiratory distress syndrome (ARDS) and severity of pneumonia were considered as the leading causes of all maternal mortalities [58].…”