To investigate early neonatal deaths born to pregnant women with syphilis and the risk factors.

Data were obtained from the maternal syphilis surveillance system in Zhejiang Province. Pregnant women with syphilis who delivered ≥28 weeks during January 2014 to December 2020 were included. Demographic characteristics (age, education level, occupation, gravidity, parity, adverse pregnancy history, etc.), maternal and perinatal health records, syphilis laboratory test results, syphilis treatment regimen, delivery information, and infant information were collected. Trend chi-square analysis was conducted to track the early neonatal mortality over years. Pearson correlation coefficient was used to estimate the relationship between maternal syphilis treatment and early neonatal mortality. Logistic analysis was conducted to investigate the risk factors for early neonatal death.

Among the 71 cases with early neonatal death, 49 cases (69.01%) were aged from 21 to 34 years old, 52 cases (73.24%) had middle school education, 39 cases (54.93%) had no fixed occupation, 39 cases (54.93%) had more than three gravidities, 48 cases (67.61%) were multiparas. There were eight cases (11.27%) of stillbirth abortion. Forty-nine cases (69.01%) with rapid plasma reagin circle card test (RPR) or tolulized red unheated serum test (TRUST) titer ≥1∶4. Among the 72 early neonatal deaths, 40 were males and 32 were females. The leading cause of death was preterm birth/low birth weight (56 cases, 77.78%). From 2014 to 2020, the early neonatal mortality rate of pregnant women with syphilis in Zhejiang Province decreased from 10.37‰ (24/2 314) to 1.49‰(3/2 007) (trend χ²=20.05, P<0.001). The rate of maternal antisyphilitic treatment was negatively correlated with early neonatal mortality (r=-0.895, P=0.006). Multivariate analysis showed that standard treatment reduced the risk of early neonatal death (Wald=24.845, P<0.001, odds ratio (OR)=0.181). However, RPR or TRUST titer ≥1∶4 in the last trimester (Wald=72.026, P<0.001, OR=10.112) increased the risk of early neonatal death.

Preterm birth and low birth weight are the leading causes of early neonatal death in pregnant women with syphilis. Strengthening the treatment of syphilis in pregnancy women, especially the standard treatment, is beneficial to reduce the risk of early neonatal death.

Syphilis; Risk factors; Pregnant women; Neonatal deaths; Multivariate regression analysis