There has been a considerable amount of controversy surrounding whether pregnant women with the coronavirus disease 2019 (COVID-19) are at a higher risk for poor outcomes for themselves and their babies. A recent study suggests the answer depends on the presence of symptoms at near term.
“Most pregnancy and delivery outcomes were similar between COVID-19-positive and -negative parturients.”
Study: Does The Presence Of Symptoms Affect Pregnancy Outcomes In Third Trimester In Women With SARS-CoV-2. Image Credit: MilanMarkovic78 / Shutterstock.com
Background
The severe acute respiratory syndrome coronavirus (SARS-CoV-2) has infected over 239 million people worldwide and caused the deaths of over 4.8 million. Early on in the pandemic, pregnancy was deemed a high-risk condition for COVID-19, with public health officials recommending these individuals to shelter in isolation.
Pregnancy is associated with a higher than usual toll due to respiratory illness. This is due to the nature of the peculiar physiology of pregnancy, with marked alterations in the immune system, coagulation, and activity of the heart and lungs.
Respiratory viruses may therefore cause severe illness in pregnancy, which impacts the fetus as well. Some earlier studies have found that COVID-19 may increase the risk of intensive care unit (ICU) admission, the need for invasive ventilation or extracorporeal membrane oxygenation (ECMO), and death.
Other studies have shown that preterm delivery and Cesarean section rates are increased with COVID-19 in pregnancy. However, there is little direct evidence to support a definitive conclusion.
As many as one in ten pregnant women are COVID-19-positive at the time of admission to the labor ward. Almost 80% of this group are asymptomatic, which underlines the need for universal testing in this population.
The current study, which was published in The Journal of Maternal-Fetal and Neonatal Medicine, discusses the risk of COVID-19-induced severe maternal illness in pregnant women who develop symptomatic illness in the third trimester.
Study findings
The current study was conducted at Israel’s Mayanei Hayeshua Medical Center and included women between 18-50 years with a single term gestation who were screened for SARS-CoV-2 infection. The subjects were either negative on screening, positive but asymptomatic, or positive and symptomatic.
Of the approximately 2,500 patients screened, 7% (170) were positive, of whom 56 were symptomatic and 116 asymptomatic. The total lymphocyte count was lower in COVID-19-positive patients, while these patients had a higher rate of gestational diabetes mellitus (GDM) than controls.
Other features, such as hypertensive disorders, intrauterine growth restriction, or mode of delivery, were not different in the various groups. Maternal complications were not increased overall; however, lymphocyte counts were lower and post-partum hemorrhage was higher in the COVID-19 group. The rates of respiratory distress syndrome and transient tachypnea of the newborn were also higher in this group.
Other fetal complications were comparable. Three newborns who were born normally to COVID-19 mothers were positive for SARS-CoV-2 at delivery, but became negative at 24 and 48 hours, thus indicating that they were false positives.
Adverse outcomes in pregnant women appear to be on the rise from healthy controls as compared to asymptomatic to symptomatic pregnant women, at an incidence of 11%, 14%, and 20%, respectively.
The adverse outcomes in the newborn were doubled in the group born to COVID-19-positive mothers. Again, the incidence rose from 3.5% in the healthy controls or asymptomatic patients to 9% in symptomatic patients.
Overall, composite adverse outcomes were doubled in the symptomatic group.
Implications
While 93% of women were negative for COVID-19 on screening at the time of admission to the labor ward, the majority of those who tested positive were also asymptomatic. Most pregnancies and deliveries failed to show a marked worsening in the group of COVID-19-positive mothers, though the preterm birth rate went down.
Gestational diabetes was more common in the symptomatic group, perhaps contributing to the somewhat more severe phenotype of the illness. While respiratory distress syndrome in the newborn was also increased, no baby became seriously ill.
This may be attributed to behavioral changes and altered practice guidelines during this period. Importantly, obstetric management was unaltered by the presence of COVID-19 at this center, which led to comparable levels of Cesarean section in mothers with or without COVID-19.
One patient had severe respiratory illness due to COVID-19, but no patient died. Most patients with symptomatic illness were discharged within days. The overall trend of composite adverse outcomes shows an increase towards progressive worsening in the symptomatic group.
“Our findings reveal that, amongst our population, COVID-19 in the third trimester of pregnancy has clinical implications, albeit at lower rates than expected once asymptomatic patients are taken into account.”
Further studies may be required to understand how differences in viral strain, patient ethnicity, epigenetic factors, and term of pregnancy at the time of infection, affect the outcome.
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