Mpox Among Pregnant Women and Their Infants in the U.S. Outbreak, 2022-2023

To describe pregnancy and treatment outcomes among pregnant and recently pregnant women with mpox and their infants reported during the clade II mpox outbreak in the United States.

Maternal, pregnancy, and infant outcomes related to mpox were monitored through the use of the enhanced methods of SET-NET (Surveillance for Emerging Threats to Mothers and Babies Network), a pregnant woman-infant-linked surveillance program. Thirteen state and local health departments collected data on pregnant or recently pregnant women with laboratory-confirmed mpox reported during August 1-December 31, 2022. Demographics, maternal health history, laboratory results, treatment, and pregnancy and infant outcomes were abstracted from medical records and linked data sources such as birth certificate data and Investigational New Drug registries.

Twenty-six pregnant or recently pregnant women with mpox in the United States were reported to the Centers for Disease Control and Prevention. Trimester of infection was known for 23 women: six (24.0%) infections occurred in the first trimester, nine (36.0%) in the second trimester, and eight (32.0%) in the third trimester. Among 23 pregnant women with known outcome, 19 had live births, three of whom delivered preterm, and four had pregnancy losses. Fourteen pregnant women received tecovirimat to treat mpox under an Investigational New Drug protocol with no adverse effects reported. Two neonates were diagnosed with mpox within 2 weeks of life; in these cases, the mothers tested positive for mpox at 2 and 12 days after delivery. Both neonates received tecovirimat, and one neonate also received vaccinia immune globulin intravenous. No adverse effects were reported after neonatal tecovirimat administration except for a suspected drug-related rash in one neonate. The association between tecovirimat and outcomes could not be evaluated because of insufficient sample size.

In this descriptive report of pregnant and recently pregnant women with clade II mpox, there were no adverse maternal outcomes. Two neonates were diagnosed with mpox among 23 pregnancies with known outcomes. There were no reported adverse events related to tecovirimat administration in pregnant mothers.