| Objective: To explore the epidemiological characteristics of syphilis pregnant women and their infants in the outpatient department of general hospitals and maternal and child health center in Yunnan,the factors affecting the vertical transmission of syphilis and the dynamic changes of syphilis serum tests,in order to provide an effective and scientific method for the prevention and control of mother-to-child transmission of syphilis and early diagnosis of congenital syphilis.Methods: Pregnant women with syphilis who attended the First Affiliated Hospital of Kunming Medical University,Wenshan State Maternal and Child Health Hospital and Zhaotong Maternal and Child Health Hospital from January 2010 to December2022,and their infants who delivered and were followed up with syphilis serology tests were used as the study population.Demographic and clinical data of pregnant women with syphilis,their spouses and their infants were collected.The pregnant women with syphilis and their infants were followed up according to the prescribed follow-up time.The peripheral blood of infants born to pregnant women with syphilis during delivery and at each follow-up time point was collected.After follow-up,it was determined as congenital syphilis group and syphilis passive antibody group.TPPA,TRUST,Treponema pallidum Ig M and Ig G antibody tests were performed on peripheral blood of pregnant women with syphilis and their infants.A dynamic follow-up database was set up in Excel,and SPSS 27.0 statistical software was used to analyze the data.To study the epidemiological characteristics of syphilis pregnant women and their infants,the precipitating factors of congenital syphilis,the dynamic changes of syphilis serum test and the related influencing factors..Results: A total of 181 infants with syphilis passive antibodies and 179 of their mothers(including 2 twins)and 9 children with congenital syphilis and their mothers were collected.(1)The age of delivery of syphilis-infected pregnant women was mainly between 21 and 35 years old,and the occupational composition of syphilis-infected pregnant women was relatively wide,farmers and unemployed people are the majority.The majority of syphilis-infected mothers were primiparous,with multiple pregnancies predominating.160 cases(85.11%)of syphilis were detected in the antenatal examination of 188 syphilis-infected mothers,15 cases(7.98%)were detected in the preconception general medical examination,11 cases(5.85%)were detected in the preparation examination,1 case(0.53%)was detected in the marriage examination,and1 case(0.53%)was detected in the delivery.All 188 cases were treated with benzathine penicillin or ceftriaxone for syphilis,including 9 cases of mothers of children with congenital syphilis.184 cases(97.87%)of mothers had latent syphilis.(2)Among the181 infants with syphilis passive antibodies,there were 100 boys and 81 girls,with a male to female ratio of 6:5,the average birth weight was(2734.9±344.9)g.Among the 10 children with congenital syphilis,the average birth weight was(2518.5±285.1)g.(3)All 9 cases of congenital syphilis were latent syphilis and were treated with benzathine penicillin and one was treated with ceftriaxone sodium.(4)There were 59infants(47.97%)were born with TPPA titers ≥1:1280 in the syphilis passive antibody group,and 64 infants(52.03%)were born with TPPA titers <1:1280 at birth.All 9infants in the congenital syphilis group were born with a TPPA titer ≥1:1280;64infants(52.03%)were born with TRUST positive in the syphilis passive antibody group.All 9 infants in the congenital syphilis group were TRUST positive at birth;18 cases(14.63%)in the syphilis passive antibody group and 4 cases(44.45%)in the congenital syphilis group were born to mothers with TRUST titers ≥1:8,105 cases(85.37%)in the syphilis passive antibody group and 5 cases(55.56%)in the congenital syphilis group were born to mothers with TRUST titers <1:8;22 cases(17.89%)in the syphilis passive antibody group and 3 cases(33.33%)of congenital syphilis among those whose mothers were diagnosed with syphilis before pregnancy,101 cases(82.11%)in the syphilis passive antibody group and 4 cases(44.45%)of congenital syphilis among those diagnosed with syphilis during antenatal examination,and 2 cases of congenital syphilis in which the mothers’ syphilis was detected at birth.Univariate analysis showed that infants with TPPA titer ≥ 1:1280 at birth were more likely to suffer from congenital syphilis than those with TPPA titer < 1:1280 at birth.Infants with positive TRUST at birth were more likely to suffer from congenital syphilis than those with negative TRUST at birth.Infants with mothers’ TRUST titer ≥1:8 during delivery were more likely to suffer from congenital syphilis than those with mothers’ TRUST titer <1:8 during delivery.Infants born to women with maternal syphilis diagnosis at delivery were more likely to suffer from congenital syphilis than those diagnosed with syphilis before pregnancy or prenatal examination(P<0.05).Multivariate logistic regression analysis showed that the time of maternal syphilis diagnosis was an independent risk factor for congenital syphilis in children born to syphilis mothers(0R=18.894,P<0.05).(5)TRUST positive of infants in syphilis passive antibody group turned negative at 3months old.The average negative conversion time of TPPA in boys was slightly shorter than that in girls.The overall trend of TPPA titer negative conversion time in syphilis passive antibody group was that the lower the TPPA titer at birth,the shorter the average negative conversion time.The average negative conversion time of TPPA in TRUST negative group was shorter than that in TRUST positive group at birth.(6)The TPPA titer of infants in the syphilis passive antibody group decreased most rapidly in the first3 months,up to 4-8fold,and completely turned negative at 18 months.(7)The TPPA titer of infants born to mothers with syphilis decreased by 4 times at 3 months of age,or decreased to 1:80 at any follow-up time at 3 months,6 months and 9 months of age,suggesting that it was syphilis passive antibody.The ROC curve analysis showed that the area under the curve was >0.7 at 3 months,6 months and 9 months of age,indicating diagnostic value,and the area under the curve for TPPA titer at 3 months was 0.8984 with 82.9% sensitivity and 100% specificity;the area under the curve for TPPA titer at6 months was 0.9390 with 89.4% sensitivity and 100% specificity;the area under the curve for TPPA titer at 9 months was 0.9675 with 93.5% sensitivity and 100%specificity.The TPPA titer decreased to 1:80 at 9 months of age had the best predictive effect.(8)There was a positive correlation between the TRUST titers of the mothers at delivery and the TRUST titers of the newborns at birth in the syphilis passive antibody group and the congenital syphilis group(r=0.5938,p<0.0001).(9)The detection sensitivity of Ig G antibody in peripheral blood of infants born by pregnant women with syphilis was higher than that of Ig M antibody.The difference in Ig G antibodies induced by Tp N15 and Tp N47 was statistically significant between the syphilis passive antibody group and the congenital syphilis group(P=0.026<0.05).Conclusion:(1)Pregnant women with syphilis are distributed in all groups.It is very important to carry out prevention of mother-to-child transmission of syphilis and syphilis screening for pregnant women in active sexual life,low educational level,low income,no fixed occupation or farming.(2)Mother-to-child transmission of syphilis is influenced by maternal infection status and the serological response of the infant.Infants born with a positive TRUST titer,infants born with a TPPA titer ≥1:1280,infants born with a maternal TRUST titer ≥1:8,and maternal syphilis diagnosed at antenatal screening are susceptibility factors for congenital syphilis.detection of syphilis at antenatal screening is an independent risk factor for congenital syphilis in infants.Strengthening pre-pregnancy,prenatal syphilis screening and sexual partner syphilis screening are important measures to block mother-to-child transmission of syphilis.(3)Pay attention to the change of TRUST titer in pregnant women with syphilis,and closely observe the effect of anti-syphilis treatment in patients with TRUST titer ≥1:8.The TRUST titer should be negative or at least reduced to below1:8 before delivery.(4)The lower the TPPA titer and the negative TRUST at birth,the shorter the average negative conversion time.(5)infants with TPPA titer decreased by4 times at 3 months of age,or decreased to 1:80 at any follow-up time of 3 months,6months and 9 months,can be exclude congenital syphilis,and the TPPA titer of 9months decreased to 1:80 was the most sensitive predictor.TPPA titers should be used as an early differential diagnosis method between congenital syphilis and syphilis passive antibody.(6)The Ig G induced by Tp N15 and Tp N47 in peripheral blood of infants born by pregnant women with syphilis is highly sensitive in the detection of congenital syphilis,which is expected to provide laboratory basis for shortening the diagnosis time of fetal syphilis. |
