Infants born to women infected with the hepatitis C virus (HCV) faced twice the risk of stays in the neonatal ICU (NICU) and 2.7 times the risk of low birth weight, a new analysis finds, even when researchers adjusted their data to control for injectable drug use and maternal medical comorbidity.
Clinicians should be “aware that the infants of pregnant people with HCV may have a high rate of need for higher-level pediatric care,” said Brenna L. Hughes, MD, MSc, chief of maternal fetal medicine at Duke University Medical Center, Durham, N.C. She spoke in an interview about the findings, which were presented at the meeting sponsored by the Society for Maternal-Fetal Medicine.
As Dr. Hughes noted, “HCV remains a serious problem in pregnancy because it often goes undiagnosed and/or untreated prior to pregnancy. It can be passed to infants, and this can cause significant health-related outcomes for children as they age.”
For the multicenter U.S. study, researchers identified 249 pregnant mothers with HCV from a 2012-2018 cohort and matched them by gestational age to controls (n = 486). The average age was 28; 71.1% of the cases were non-Hispanic White versus 41.6% of the controls; 8.4% of cases were non-Hispanic Black versus 32.1% of controls (P < .001 for race/ethnicity analysis); and 73% of cases were smokers versus 18% of controls (P < .001). More than 19% of cases reported injectable drug use during pregnancy versus 0.2% of controls (P < .001).
The researchers adjusted their findings for maternal age, body mass index, injectable drug use, and maternal comorbidity.
An earlier analysis of the study data found that 6% of pregnant women with HCV passed it on to their infants, especially those with high levels of virus in their systems. For the new study, researchers focused on various outcomes to test the assumption that “adverse pregnancy outcomes associated with HCV are related to prematurity or to ongoing use of injection drugs,” Dr. Hughes said.
There was no increase in rates of preterm birth or adverse maternal outcomes in the HCV cases. However, infants born to women with HCV were more likely than the controls to require a stay in the NICU (45% vs. 19%; adjusted relative risk, 1.99; 95% confidence interval, 1.54-2.58). They were also more likely to have lower birth weights (small for gestational age < 5th percentile) (10.6% vs. 3.1%; ARR, 2.72; 95% CI, 1.38-5.34).
No difference in outcomes was seen when HCV cases with viremia (33%) were excluded.
“The most surprising finding was that the need for higher-level pediatric care was so high even though there wasn’t an increased risk of prematurity,” Dr. Hughes said.
She added it’s not clear why NICU stays and low birth weights were more common in infants of women with HCV. “It is possible that the higher risk of need for higher-level pediatric care was related to a need for observation or treatment due to use of opioid replacement therapies with opioid agonists.” As for lower birth weight, “there may be other unmeasured risk factors.”
Tatyana Kushner, MD, MSCE, of the division of liver diseases at Icahn School of Medicine at Mount Sinai, New York, said in an interview that the study adds to limited data about HCV in pregnancy. “These findings have been demonstrated in prior studies, and it would be important to tease apart whether [low birth weight] is related to the virus itself or more related to other confounding associated factors such as maternal substance use as well as other associated social determinants of health among women with HCV.”
As for the study’s message, Dr. Kushner said it makes it clear that “hepatitis C adversely impacts outcomes of pregnancy and it is important to identify women of childbearing age for treatment early, ideally prior to pregnancy, in order to improve their pregnancy outcomes. In addition, treatment of hepatitis C during pregnancy should be explored further to determine if treatment during pregnancy can improve outcomes.”
At the moment, she said, “there are ongoing studies to delineate the safety and efficacy of hepatitis C treatment during pregnancy. Given that we are screening for hepatitis C during pregnancy, we need clear recommendations on the use of direct-acting antivirals in people who screen positive.”
The study was funded by the National Institute of Child Health and Human Development. The authors have no disclosures. Dr. Kushner disclosed research support (Gilead) and advisory board service (Gilead, AbbVie, Bausch, GlaxoSmithKline, and Eiger).