July 7, 2020

Risk of preterm delivery is lower in women diagnosed with SARS-CoV-2 infection in the early preterm period

By Denise Baez

NEW YORK -- July 7, 2020 -- Among pregnant women hospitalised with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the risk of preterm delivery was significantly lower among women diagnosed in the early preterm period compared with those diagnosed in the late preterm period, according to a study published in the American Journal of Perinatology.

In addition, the study also showed that the majority of the women diagnosed in the early preterm period recovered from the viral infection and were discharged home undelivered. Among the women who did deliver in the preterm period, the majority were indicated and delivery was not due to spontaneous preterm labour.

“Our data add to the limited existing literature regarding clinical outcomes of SARS-CoV-2 infection in the viable preterm period,” wrote Moti Gulersen, MD, North Shore University Hospital-Northwell Health, Manhasset, New York, and colleagues. “Our data are reassuring, suggesting that the risk of preterm delivery during infection with SARS-CoV-2 is significantly lower among women diagnosed in the early preterm period compared with the late preterm period and that the majority of these women recovered from infection and were discharged home. Furthermore, of the deliveries that occurred in the preterm period during infection, the majority were indicated and not due to spontaneous preterm labour. This represents an important finding when counselling women regarding the risks associated with SARS-CoV-2 infection in the viable preterm period.”

Dr. Gulersen and colleagues analysed data from all (n = 65) women diagnosed with SARS-CoV-2 infection between 23 and 37 weeks of gestation between March 13 and April 24, 2020 at 7 hospitals within the Northwell Health system in New York. Cases were stratified into 2 groups based on gestational age at diagnosis of SARS-CoV-2 infection: early preterm (23-336/7 weeks of gestation) versus late preterm (34-366/7 weeks of gestation).

Of the women, 36 (55.4%) were diagnosed in the early preterm period and 29 (44.6%) were diagnosed in the late preterm period.

The rate of preterm birth during hospitalisation was significantly lower among women diagnosed in the early preterm period compared with late preterm (19.4% vs 62%; P  = 0.001).

Of the 25 patients who delivered during hospitalisation, the majority (64%) were indicated deliveries. There were no deliveries <33 weeks of gestation for worsening coronavirus disease 2019 (COVID-19) and severity of disease did not alter the likelihood of delivery during hospitalisation with SARS-CoV-2 infection (adjusted odds ratio [aOR] = 0.64; 95% confidence interval [CI], 0.24-1.59).

On multivariable analysis, increased maternal age was associated with a lower likelihood of delivery during hospitalisation (aOR = 0.77; 95% CI, 0.58-0.96), while later gestational age at diagnosis of SARS-CoV-2 infection was associated with a higher likelihood of delivery during hospitalisation (aOR = 2.9; 95% CI, 1.67-8.09). Body mass index, race/ethnicity, presence of comorbid conditions, and severity of disease were not associated with likelihood of preterm birth during the course of infection.

“In our adjusted analysis, the likelihood of preterm birth during hospitalisation with SARS-CoV-2 infection depended on maternal age and gestational age,” the authors wrote. “The higher likelihood of preterm delivery associated with increasing gestational age was expected…however, as we did not have a control group, it is unclear whether the risk is higher or lower in the setting of SARS-CoV-2 infection. The lower likelihood of preterm delivery associated with increasing maternal age was unexpected. Older age in the nonpregnant population has been demonstrated as a risk factor for adverse outcomes associated with SARS-CoV-2 infection. Nevertheless, age as a risk factor for adverse outcomes in the pregnant population requires further study.”

SOURCE: American Journal of Perinatology