Serological changes for syphilis in infants born to treated syphilitic mothers / 中华围产医学杂志

ABSTRACT

Objective To explore the serological variations for syphilis in infants delivered by treated syphilitic mothers and its influencing factors. Methods Totally, 146 singleton gravidas, who had been treated for syphilis during pregrancy from January 2006 to January 2008 in our hospital, were chosen. Rapid plasma reagin(RPR) and treponema pallidum particle agglutination assay (TPPA) of these mothers before delivery and of the newborns within 3 d after delivery were tested and 92 of the 146 babies were followed up until the age of 24 months. Results (1) Among the 146 neonates, 104 (71.2%) were positive for both RPR and TPPA and 140 (95.9%) TPPA positive only. The RPR positive rate in neonates born to RPR+ + TPPA+ mothers were higher than those born to TPPA+ (only) mothers (81.4% vs 36.4%,χ2 = 25. 3, P<0. 01). 90.4% of the RPR+ neonates (94/104) showed lower or equivalent RPR titers compared to their mothers. (2) Among the 92 babies bein g followed up, the seroreversion of RPR were found in 98. 2%(n = 56) of the 57 babies, who were RPR+ +TPPA+ at delivery, at the 6 months and 100% (n=57) within 8 months, with the peak time within 2 months after birth (78. 9%, n = 45). While, 100% of the babies were found to be TPPA-within 24 mo with the peak time at 10～18 mo (64. 9%, n = 37). For those babies with TPPA+ at delivery, all turned to be TPPA- at 18 mo, with the peak time at 6 ～ 12 mo (57. 1%, n = 20). (3) The seroreversion time of babies with maternal RPR between 11～14 was later than those with maternal RPR (P<0.05). The seroreversion time of babies with maternal RPR titer of 14 was longer than those with maternal RPR titer of 1 > 1 [(2.5±0.8) mo vs (1. 2±0. 4) mo,P<0. 01]. However, the maternal RPR titer did not affect the TPPA reversion time (P > 0.05). The seroreversion time of RPR in infants with neonatal RPR titer of 1 4 was later than those with neonatal RPR titer of 11 [(3.7±0. 9) mo vs (2. 3±0. 6) mo,P<0. 01], and babies with RPR titer at 1 1 - 14 showed longer duration than those with neonatal RPR- in TPPA seroreversion [(11. 2±2. 8) mo, (12.2±2.9) mo, and (11.0±2.2) mo vs ( 6. 9±2. 1) mo, P< 0.01, respectively]. Conclusions Most infants born to syphilitic mothers are serological positive for syphilis despite of standard maternal treatment during pregnancy. Infants, with higher maternal RPR titer during the pregnancy or at delivery, may persist to be serological positive for syphilis for a longer perieod, but all will turn to negative finally. Long term follow up is recommended for serological positive infants, and the diagnosis of congenital syphilis should be cautious.