Can pregnant women transmit COVID-19 to their infant during delivery?

A multicentre descriptive study in Spain has not detected any transmission of the novel coronavirus (COVID-19) during delivery or throughout the first month of life in the newborns. In addition, the rates of exclusive breastfeeding at discharge and at 1 month of age are lower than expected.

“Considering the proven benefits of breastfeeding on both the mothers’ and newborns’ health, we believe it is crucial to find new strategies to improve the proportion of these newborns that receive breastmilk in their first days of life and onwards,” the researchers said.

Sixteen Spanish hospitals were involved in this study, which reviewed medical records of 242 pregnant women diagnosed with COVID-19 from 13 March to 31 May 2020, when they were in their third trimester of pregnancy. These mothers and their 248 newborn infants were monitored until the infant was 1 month old.

Sixty-three women (26 percent) had undergone caesarean section (C-section). Coughing (33 percent) and fever (29.7 percent) were the initial clinical symptoms. Mothers hospitalized due to COVID-19 pathology had a higher risk of ending their pregnancy via C-section (p=0.027), while newborns whose mothers had been admitted due to COVID-19 were prone to premature delivery (p=0.006). [Pediatr Infect Dis J 2020;39:e393-e397]

Almost half of the newborn infants (n=115; 46.3 percent) were admitted to the neonatal unit, of whom 86 (75.6 percent) were only admitted due to organizational circumstances. None of the infants died, and no vertical or horizontal transmission was detected.

With regard to the type of feeding, 41.7 percent of the newborns were breastfed exclusively at discharge and 40.4 percent at 1 month.

“The clinical presentation in pregnant women in our study was similar to what other groups have recently published,” the researchers said. In addition, “death due to COVID-19 in pregnant women is very rare, and only a few sporadic cases have been published. [Lancet 2020;395:809-815; JAMA Pediatr 2020;174:722-725; Int J Gynaecol Obstet 2020;150:47-52]

Notably, most women did not need pharmacologic treatment for their COVID-19 infection during pregnancy, but when deemed necessary, the preferred and officially recommended options were hydroxychloroquine, azithromycin, and antiretroviral treatment. [Am J Obstet Gynecol 2020;222:521-531; Am J Obstet Gynecol 2020;222:415-426]

Evidence on a possible vertical transmission remains scant to date. In the present study, 11 positive results were detected in the first samples that turned out to be negative in the following samples. Two positive results were also found in the second sample tests; both had previous negative results, and none of them had any symptoms. They were then considered to be false positives. [JAMA 2020;323:1848-1849; Am J Perinatol 2020;37:861-865; Obstet Gynecol 2020;136:65-67]

“Moreover, [p]rematurity rate was higher in our study than expected in standard conditions, more so in mothers who required admission due to the COVID-19 infection. Other scientific publications have detected a higher rate of prematurity in pregnant women with COVID-19 infection,” the researchers said. [Int J Infect Dis 2020;95:294-300; Ultrasound Obstet Gynecol 2020;56:15-27; J Perinatol 2020;40:820-826; Int J Gynaecol Obstet 2020;150:47-52; Lancet 2020;395:809-815]

“However, prematurity could derive from needing to end the gestation due to maternal COVID 19-related complications, and not specifically due to direct intrauterine infection,” they added.