Objectives | Given recent increases in congenital syphilis (CS) in the United States, we describe national trends in the number of CS-related stillbirths, describe CS-related stillbirths by gestational age, and compare characteristics of women delivering CS-related stillbirths to those delivering full term and preterm liveborn CS infants to provide important clinical insight. | | Methods | CS is nationally notifiable with case reports submitted to Centers for Disease Control and Prevention (CDC). We analyzed reported cases of CS born during 20152019, categorizing birth outcomes as stillbirth, preterm <37 weeks, or full term 37 weeks; cases with unknown vital status or gestational age were excluded. We calculated frequencies of maternal clinical characteristics by birth outcome, including receipt of prenatal care, stage of syphilis, and highest reported titer during pregnancy. | | Results | Of the 5,269 CS cases reported to CDC for 20152019, 5,127 (97.3%) had known vital status and gestational age. Among these, 307 (6.0%) were stillbirths. While the number of CS-related stillbirths increased each year during 20152019 (from 2994), the proportion of CS cases reported as stillbirths did not vary considerably across the period (range: 5.1%7.3%). Median gestational age at delivery for CS-related stillbirths was 30 weeks (interquartile range: 2733 weeks). Most CS cases were born to mothers with early latent (31.4%) or late/unknown duration (59.7%) syphilis, though mothers of stillborn infants were 2.3 times as likely as mothers of full term liveborn infants to have secondary syphilis (10.8% vs. 4.6%). Adverse pregnancy outcomes were more likely to have a high maternal syphilis titer; 80.8% of stillbirth, 58.1% of preterm, and 40.2% of full-term deliveries occurred among women with a titer 1:32 during pregnancy. Among women delivering a CS-related stillbirth, 33 (10.7%) had evidence of syphilis seroconversion during pregnancy. Most mothers delivering a CS-related stillbirth (53.4%) did not receive prenatal care, compared to mothers delivering full term liveborn CS infants (18.4%). | | Conclusions | Increases in CS-related stillbirths in the United States reflect increases in CS cases; without prevention efforts, CS could become a larger contributor to overall U.S. stillbirth levels. Understanding when CS-related stillbirths occur, as well as the differences between women delivering CS-related stillbirths and women delivering liveborn CS infants (higher titer, syphilis stage, and prenatal care) may aid with stillbirth prevention. Overcoming barriers to prenatal care is essential for preventing CS stillbirths. Low rates of prenatal care also highlight the importance of syphilis testing outside traditional settings and at the time of stillbirth delivery. Delivery may provide a rare interaction with the healthcare system enabling syphilis testing and treatment, and prevention of future CS-related adverse outcomes.