2.1.Study design, ethical considerations, and participants
In the current retrospective cohort study, all pregnant women suspected of contracting COVID-19 were admitted to Ayatollah Rohani Hospital, Babol, Iran, for delivery between February 10 and May 20, 2020. This study protocol was approved by the Ethics Committee of Babol University of Medical Sciences, Babol, Iran (Code: IR.MUBABOL.REC.1399.092). Also, written informed consent was obtained from the patients. All women with COVID-19 enrolled in the recent research were diagnosed and managed according to WHO interim guidance for 2019 novel coronavirus (8). In another word, all women with laboratory-confirmed (positive in nasopharyngeal/ throat swab specimens by reverse transcription- polymerase chain reaction (RT-PCR)) COVID-19 infection or suggestive findings on high-resolution computed tomography (HRCT) of the chest were included, while suspected patients with similar symptoms were excluded from the study. According to the instructions at the time, a cesarean section was recommended unless vaginal delivery progressed rapidly. Due to insufficient evidence, a cesarean section was recommended to minimize the presence of the mother suspected of having COVID-19 in labor and reduce the risk of infection acquisition. Newborns have also undergone neonatal surveillance in neonatal accordance with national guidelines. Nasopharyngeal swabs for RT-PCR were taken in the neonates 24 and 72 hours after birth. Clinical signs such as respiratory distress, milk intolerance, and decreased reflexes were also recorded. If there were no contraindications to breastfeeding, the infant was fed with her or his breast milk. After 72 hours, if the baby has stabilized clinical condition and does not requires hospitalization, she/ he would be discharged. An outpatient visit was made to infants within the first week of discharge. The neonate clinical outcomes were followed for 4 weeks. Furthermore, at the end of the first month, the general condition and weight of newborns were requested over the phone. Infants who needed serum and antibiotics for any reason (e.g., prematurity, treatment of respiratory distress, clinical sepsis) were visited twice in the first month following discharge.
The epidemiological, clinical presentations such as respiratory distress, milk intolerance, and decreased reflexes, laboratory, and radiological findings, medications, and outcomes data were collected with a data collection checklist from electronic medical records. All data were reviewed by two trained nurses.
2.3.RT-PCR assay for SARS-CoV-2 detection
Mother and neonatal nasopharyngeal/ throat swabs were collected and analyzed to detect SARS-CoV-2 RNA using RT-PCR. Also, viral RNA was freshly extracted using the Ribospin vRD plus Kit (GeneAll, Seoul, South Korea) according to the manufacturer’s instructions. Isolated RNA was analyzed by LightMix® SarbecoV E-gene kit (TIB Molbiol, Berlin, Germany) with LightCycler Multiplex RNA Virus Master (Roche). Specimen collection and laboratory testing followed WHO guidance (9, 10).
Data were analyzed using SPSS version 16. Continuous variables were expressed as the range. Also, categorical variables were expressed as number (%).