Impact of SARS-CoV-2 infection in pregnant women on maternal and perinatal outcomes

In a study posted to the preprint server Research Square*, researchers conducted a retrospective cohort analysis by reviewing medical records of pregnant women to examine the impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) maternal infection on maternal and perinatal outcomes.

Study: Maternal and perinatal outcomes in pregnant women with SARS-CoV-2 infection: a retrospective observational study. Image Credit: Velishchuk Yevhen/Shutterstock

Since the coronavirus disease 2019 (COVID-19) outbreak in December 2019, Spain has reported approximately 3.8 million SARS-CoV-2 cases and 80000 COVID-19-related deaths as of September 2021. Pregnant women constitute a high-risk group for SARS-CoV-2 infection due to pregnancy-induced physiological changes.

Study design

In this study, the researchers performed a retrospective analysis of a hospital database of pregnant women admitted to Infanta Leonor University Hospital, Madrid, Spain, between March 2020 to December 2020.

The infected group and non-infected group were composed of SARS-CoV-2-positive and SARS-CoV-2-negative pregnant women, respectively, tested during the third trimester of pregnancy or at the time of delivery. SARS-CoV-2 infection was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) of the nasopharyngeal swab sample. For both groups, exclusion criteria were based on multiple pregnancies and delivery outside the hospital. During the study period, 86 SARS-CoV-2-positive (infected group) and 1262 SARS-CoV-2-negative (non-infected group) pregnant women were analyzed.

Information regarding the demographic features, maternal comorbidities, obstetrics history, and previous birth records of pregnant women was extracted from the maternal medical history of the hospital database. Data were retrieved and managed by a secured web-based software called Research Electronic Data Capture (REDCap) tools.

Findings

From the data collected, researchers observed that the average maternal age in the SARS-CoV-2-infected group was 30 years, and in the non-infected group, it was 31.5 years. Among the infected pregnant women group, 34.5% belong to Spain while 65.5% were outside of Spain. There were 48.3% nulliparous women and 51.7% multiparous women in the infected group, while in the non-infected group, the percentages were 44.4% and 55.6%, respectively.

The researchers observed that in the infected group, percentages of maternal comorbidities such as thyroid dysfunction, pulmonary comorbidities, hematologic comorbidities, obesity, hypertension disease, and pre-gestational diabetes were 4.64%, 1.16%, 2.32%, 10.47%, 4.65%, and 5.8%, and in the non-infected group they were 0.95%, 0.39%, 0.85%, 6.34%, 1.58%, and 1.58% respectively.

Out of the 86 SARS-CoV-2-positive pregnant women, 49 (57%) were symptomatic while 37 (43%) were asymptomatic. Further, symptomatic pregnant women were divided into three categories – mild, moderate, and severe, whose proportion was 80.2%, 11.6%, and 8.1%, respectively. Also, women with severe symptoms showed pneumonia complications.

The most frequent clinical symptom in infected women was ageusia (56.9%), followed by fever (36%), headache (16.3%), and myalgia (11.6%). At the time of COVID-19 diagnosis, the average gestational age was 38 weeks, and the average duration of SARS-CoV-2 infection was 15 days.

The researchers analyzed obstetrics outcomes and showed that women in the infected group were obese (9.29%), had chronic hypertension (4.6%), and pre-gestational diabetes (4.65%). In comparison, in the non-infected group, the percentages were 5.9%, 1%, and 0.9%, respectively.

The team observed no complications like gestational diabetes, pre-eclampsia, and fetal growth retardation in the infected group. Still, interestingly, in the non-infected group, there was 1.1% gestational diabetes and 1.01% fetal growth retardation.

In the infected group, 83.3% were vaginal deliveries, and 16.7% deliveries were by cesarean section, while in the non-infected group, there were 77.9% vaginal deliveries and 21.8% cesarean sections.

The range of gestational age at delivery was 38.8 to 39.6 weeks in infected pregnant women, and in the non-infected group, this range was 39 to 41 weeks. In the infected group, no fetal death was observed, while in the non-infected group, there was one case of antepartum fetal death.

Regarding the neonatal outcomes, the researchers observed that the mean birthweight; appearance, pulse, grimace, activity, and respiration (APGAR) score; and umbilical artery pH were 3210 g, 9.64, and 7.30 in infected pregnant women and in non-infected pregnant women, they were 3240g, 9.71, and 7.29, respectively.

The researchers showed that in the infected group, 9.5% of neonates born hospitalized to the neonatal intensive care unit (NICU), while in the non-infected group, only 1.2% were admitted to NICU.

Conclusion

The study's findings showed that in Spain, during the initial two COVID-19 pandemic waves, among SARS-CoV-2-positive obstetric patients, a high percentage were asymptomatic patients or patients with mild symptoms. In SARS-CoV-2-positive pregnant women, there was a higher incidence of maternal comorbidities, but no effect was observed in pregnancy progression, gestational age at delivery, or cesarean section frequency.

The findings showed that in SARS-CoV-2-infected mothers, there was no worsening in pregnancy prognosis in terms of birth weight, but there was an unexplained increase in neonatal admissions in NICU.

*Important notice

Preprints with Research Square publish preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information.