To investigate the effect of maternal syphilis infection and perinatal outcome after standardized mother-to-child block treatment.

Total of 485 pregnant women and their newborns diagnosed as complicated syphilis during pregnancy were recruited from the Department of Obstetrics and Gynaecology, Beijing Ditan Hospital, Capital Medical University from January 1st, 2015 and June 30th, 2020. The 485 pregnant women were classified to TRUST ≥ 1︰16 group (100 cases with high titre) and TRUST ≤ 1︰8 group (385 cases with low titre) according to TRUST titre of syphilis before delivery. While the 485 pregnant women were divided to standardized treatment group (405 cases) and unstandardized treatment group (80 cases) according to whether received standard treatment of syphilis or not. TRUST titers in pregnant women and newborns, and adverse outcomes (preterm delivery, low birthweight infants, intrauterine or neonatal death, birth defects, neonatal infection, intrauterine distress, neonatal asphyxia, congenital syphilis) of mother and infants were analyzed by Pearson chi-square test, continuous-corrected chi-square test or Fisher’s exact probability method.

For the cases in TRUST ≥ 1︰16 group, the incidence of congenital syphilis in newborns were 12.0% (12/100) and 0% (0/385) (χ² = 47.372, P < 0.001), the incidence of birth defects were 17% (17/100) and 1.7% (6/385) (χ² = 41.9, P < 0.001), the incidence of preterm birth were 13.0% (13/100) and 5.1% (20/385) (χ² = 7.626, P = 0.009), the incidence of neonatal infection were 39.0% (39/100) and 2.7% (10/385) (χ² = 115.82, P < 0.001), the incidence of low birth weight infants was 6.0% (6/100) and 1.3% (5/385) (χ² = 7.915, P = 0.013) compared to those of TRUST ≥ 1︰8 group, all with significant differences. The cases in standardized treatment group compared to those of unstandardized treatment group, the decrease of pregnant TRUST titers compared to pretreatment were 68.0% (276/405) and 33.3% (27/80) (χ² = 33.717, P < 0.001), the negative rate of TRUST titer at birth were 57.8% (235/405) and 28.6% (23/80) (χ² = 22.995, P < 0.001), the incidence of preterm birth were 5.10% (21/405) and 14.3% (12/80) (χ² = 10.148, P = 0.003), the incidence of low-weight infants were 1.48% (6/405) and 6.25% (5/80) (χ² = 6.853, P = 0.022), the incidence of birth defects were 1.7% (7/405) and 20.0% (16/80) (χ² = 45.409, P < 0.001), the incidence of neonatal infection were 1.4% (6/405) and 53.7% (43/80) (χ² = 200.948, P < 0.001), the innate syphilis infection rate were 0% (0/405) and 15% (12/80) (χ² = 56.23, P < 0.001), all with significant differences.

The higher the maternal serum TRUST titer before birth, the higher incidences of neonatal birth defects, congenital syphilis, neonatal infection, premature birth, and low birthweight children; standard drug treatment during pregnancy could effectively treat syphilis during pregnancy, patients could obtain good pregnancy outcomes and neonatal outcomes.