One year into the SARS-CoV-2 pandemic: perinatal outcome and data on the transmission of 116 pregnant women

Introduction

The Department of Gynecology and Obstetrics in the Clinic Ottakring is the COVID-19 specialized obstetric department for Vienna and it has treated 98 women who tested positive for SARS-CoV-2 while giving birth, and 18 pregnant women who needed hospitalization but could be discharged still pregnant after recovery from COVID-19 until April 2021. A standard operating procedure was established early into the pandemic and subsequently updated more than 10 times to reflect the latest scientific findings on pregnant women as a high-risk group [1], [2], [3], [4], [5]. Based on these findings and earlier publications on the perinatal outcome in the Clinic Ottakring [6], pregnant women are now considered a high-risk group in Austria and therefore they have been prioritised in terms of access to vaccinations against COVID-19 by the National Vaccination Board [7].

Despite reports of neonatal COVID‐19, SARS‐CoV‐2 has not been consistently isolated in perinatal samples and there is inconclusive evidence regarding congenital, intrapartum, and postnatal maternal-fetal-neonatal SARS-CoV-2 infections [8, 9].

As we are still learning in the context of the ongoing pandemic, especially about the effects of infections on the mother, pregnancy and child, data on infection-rates, clinical outcomes and transmission is key to the most effective perinatal care.

Materials and methods

Clinical data was collected for 118 pregnant women who tested positive for SARS-CoV-2 and were hospitalized between May 2020 and April 2021 in the Clinic Ottakring. Evidence of vertical transmission was assessed by testing for SARS-CoV-2 in amniotic fluid, cord blood, and neonatal pharyngeal swab samples. Informed consent was obtained from all individuals included in this study.

Results

A total of 118 women eligible for the study were hospitalized in the Clinic Ottakring, among whom 98 women delivered during their hospitalization, and 18 women could be discharged still pregnant after recovery from COVID-19. All participants were tested positive for SARS-CoV-2 using polymerase chain reaction (PCR). Most women (n=83; 70.3%) were asymptomatic. 19.5% (n=23) of the pregnant women who tested positive for SARS-CoV-2 and were hospitalized at the Clinic Ottakring needed hospitalization primarily because of their COVID-19 symptoms. Sixteen patients (8.6%) required oxygen support, eight (6.9%) were admitted to a critical care unit and six of them needed intubation (5.2%). This means that 22.9% (n=8) of all women who showed symptoms required critical care. One intubated woman had to be transferred for extracorporeal membrane oxygenation (ECMO), and one patient died due to her critical condition caused by COVID-19 eight days after cesarean section at 31+6 gestational weeks. The characteristics of the population are shown in Table 1.

Swabs of the amniotic fluid of 45 women were collected. Furthermore, we were able to collect 53 swabs of cord blood and 44 swabs of breast milk. In 13 patients, swabs of maternal liquor were collected during spinal anesthesia. All 155 samples were tested for SARS-CoV-2 using polymerase chain reaction (PCR). Although two newborns tested positive for SARS-CoV-2 after birth, there was no virus found in any of the collected samples of amnion fluid, cord blood, breast milk or maternal liquor. The results of the histological examination of placental tissue – which was also collected – are still pending.

In 44 (44.9%) cases, a cesarean section had to be performed, and in eight cases the reason for the cesarean section was the mother´s critical condition due to COVID-19 disease. In nine cases (9.2%), a vacuum extraction was performed, in seven cases due to pathological cardiotocography (CTG), and in two cases due to arrested labor. Fifteen births were induced, and in five of these cases a secondary cesarean section was necessary.

All newborns (n=100) were tested for SARS-CoV-2 multiple times after birth, and the tests immediately after birth were all negative. Two newborns (2%) tested positive for SARS-CoV-2 on the second day after birth, one (1%) developed a pneumonia and needed high flow oxygen and systemic corticosteroids, while the other only presented fever up to 38.5 °C. Pre-term birth before 34 weeks of gestational age occurred in eight cases (8.2%) and therefore was almost four times higher than among the total population of pregnant women in Austria [10]. In all such cases an elective cesarean section was performed due to the mother´s critical condition, and the neonates were transferred to neonatal intensive/intermediate care. The neonatal outcomes are shown in Table 2.

Discussion

The figures on clinical outcomes – especially pre-term delivery, admissions to critical/intensive care units and intubation were comparable with international reports [11] and our earlier results [6]. Even though our data doesn´t encompass every single pregnant women in Vienna who tested positive for SARS-CoV-2, only the ones who were reffered to our clinic, the high rate of hospitalization among positive testet pregnant women in this study (19.5%), compared to the overall hospitlisation rate in Austria for the age between 15 and 44 of 2% [12], needs further investigation. The proportion of symptomatic women who had to be transferred to an intensive care unit (over one-fifth) is high considering that these women are young, and thus it shows how seriously COVID-19 infection must be taken among the collective of pregnant women. Early admission for close clinical controls and an early start of medication with Dexamethasone [13], [14], [15] and Remdesivir [16, 17] were established as a consequence in our clinic to meet these concerns.