In the present study, we compared women with an active intrapartum SARS-CoV-2 infection with women who had contracted SARS-CoV-2 infection during pregnancy but recovered by the time of delivery. There were no statistically significant differences between the groups in adverse maternal, obstetrical, or perinatal outcomes with the exception of higher rates of postpartum treatment and of SARS-CoV-2-positive neonates in the active-infection group. Women in the active infection-group showed a trend of higher rates of severe and critical COVID-19 disease, ICU admission, mechanical ventilation, preterm delivery, and emergent caesarean deliveries mostly related to COVID-19 severity (and not for obstetrical indications).
Although the two groups had similar baseline characteristics, their COVID-19 features differed. The active-infection group was composed mostly of asymptomatic women who were diagnosed on routine screening at hospital admission whereas a large proportion of the recovered group had sought medical care for symptoms. However, by the time of delivery, the recovered group was completely asymptomatic whereas 5 women in the active-infection group had severe disease, including 3 (3.6%) with critical disease requiring ICU admission. Overall, the rate of caesarean delivery was very high15 in the active-infection group, reaching 26.19%, and nearly half these procedures (40.9%) were performed for non-elective indications. By comparison, 17.39% of the recovered group underwent cesarean delivery, and about one-fourth of the procedures (26.2%) were for non-elective indications. The 3 patients in the active-infection group who required treatment in the ICU accounted for about one-fourth of the patients who had a cesarean delivery -- which was performed so they could undergo more aggressive treatment for the disease, including prone positioning and ECMO. Thus, it is clear that the severity of disease dictated the mode of delivery. Similarly, three out of seven (42.85%) preterm births in the active infection group were iatrogenic and only induced in order to allow more treatment options for the maternal severe infection.
The WAPM study group reported an astoundingly high rate of 11.1% for ICU admissions in pregnant women with SARS-CoV-2 infection5 and a meta-analysis by Allotey et al.16 found that pregnant women with COVID-19 had twice the likelihood of being admitted to the ICU than COVID-19-positive non-pregnant women. Our finding that none of the women in the recovered group were admitted to the ICU supports the notion that at the time of delivery, this group resembled the general pregnant population. This assumption is supported by the finding that rates of caesarean and preterm delivery were lower in the recovered group (17.39% and 10.87%, respectively) than in patients with COVID-19 reported in the literature (33%-91% and 12%-21%, respectively),9,17,18 and were closer to the values reported in the general population (19.1% and 10.6%, respectively).19,20 The majority of these women had full-term deliveries and were hospitalized for a short term thereafter; those hospitalized longer had obstetric indications unrelated to COVID-19.
We expected that women with COVID-19, even with mild to moderate disease, might be more likely to undergo induction of labor at term because of concerns about disease aggravation. Nevertheless, we found no between-group difference for this parameter. This might be explained by the large proportion of women in the active-infection group who were asymptomatic on presentation to the obstetric emergency room in active labor and were diagnosed only on routine screening according to hospital policy. Therefore, they did not require induction of labor in any case.
Of note, our results show that almost half the women in the recovered group were symptomatic, while the majority of women in the active infection group were asymptomatic. Bearing in mind that symptomatic disease is described as a possible marker for higher risk of perinatal complications,21 it is interesting that our study suggests otherwise.
Parturients with COVID-19, regardless of the status of the infection or severity of the disease, give birth in an isolated delivery room, usually unescorted by a family member. This experience can be difficult, especially for nulliparous women, and might have potentially effect the postpartum period. From the caregiver aspect, the physical distancing from the patient along with the logistics required to enter the delivery room and perform the examination, may plausibly lead to unfavourable obstetric outcomes.
Analysis of neonatal parameters yielded no significant differences in median birthweight, birthweight percentile, and proportion of SGA neonates. Rates of SGA were low: 5.95% in the active-infection group and 8.75 in the recovered group. Accordingly, Mullins et al.22 showed that SGA rates in pregnancies complicated by COVID-19 were comparable to those in in pre-COVID-19 registries.
The 7.4% rate of SARS-CoV-2-positive neonates in the active infection group was higher than the reported 2.5% overall risk of neonatal infection in women with symptomatic disease.23 This findings can be explained by our screening routine which identifies asymptomatic patients, who are as infectious as their symptomatic counterparts.24 Additionally, several studies suggested that neonatal infection rates may be higher in women with symptomatic COVID-19,25–27 possibly because of the higher viral load and longer virus-shedding period which could contribute to viral transmission from mother to newborn.28 It should also be noted that in our cohort, the majority of neonates born to recovered mothers were not tested for SARS-CoV-2, and those that were tested were frequently only swabbed once. By contrast, all neonates born to actively infected mothers were tested twice, 24 and 48 hours after delivery. Therefore, the some SARS-CoV-2-positive neonates in the recovered group may have been missed, especially those neonates born to women with a recent infection.
4.1 | Strengths and limitations
The main strengths of this study are the methodology and setting. To the best of our knowledge, there are no prior studies comparing women with active COVID-19 at the time of delivery with women who had recovered from the infection. Furthermore, as all pregnant women who are hospitalized at our institution are routinely screened for SARS-CoV-2, the active infection group is representative of the spectrum of disease severity in this population. The recovered group, on the other hand, consisted of women who were infected at any time during pregnancy, and was therefore relatively heterogenic group.
The main limitation of this study is its retrospective design. It was especially challenging to collect data regarding COVID-19 symptoms in the recovered group owing to the risk of recall bias. Additionally, it is possible that our study was underpowered by the small patient groups. Further larger scale studies are needed to corroborate our findings.
4.2 | Conclusion
We did not find a statistically significant difference between pregnant patients with an active SARS-CoV-2 infection at delivery and recovered COVID-19 pregnant women in terms of obstetric and perinatal complications. These findings suggest that labor and delivery is safe in women with an active SARS-CoV-2 infection. However, the women with an active infection showed a trend to more severe and critical COVID-19 disease, higher rates of ICU admission and mechanical ventilation, and a higher rate of cesarean delivery, especially caesarean delivery for non-elective, COVID-related indications.