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Incidence and associated factors of congenital syphilis at a tertiary care center in Thailand Cover

Incidence and associated factors of congenital syphilis at a tertiary care center in Thailand

Open Access
|Aug 2023

Figures & Tables

Clinical, radiologic, complete blood count and CSF findings of 40 neonates with congenital syphilis†

Findingsn (%)
Abnormal physical examinations (14/40 cases=35.0%)
Skin desquamation7 (17.5%)
Hepatosplenomegaly4 (10.0%)
Rash3 (7.5%)
Petechiae2 (5%)
Abnormal radiologic findings§ (6/32 cases=18.8%)
Cortical erosion1 (3.1%)
Osteolytic lesion1 (3.1%)
Radiolucent line at metaphyseal plate (osteitis)5 (15.6%)
Abnormal complete blood counts (7/40 cases=17.5%)
Anemia (Hematocrit < 40%)2 (5 %)
Thrombocytopenia (Platelet < 150,000)7 (17.5%)
Abnormal CSF fluid examinations|| (30/35 cases= 85.7%)
CSF Pleocytosis (CSF WBC > 15 cells/mm3)13 (37.1%)
Elevated CSF protein (CSF protein > 120 mg/dL)20 (57.1%)
Positive CSF VDRL2 (5.7%)

Maternal and neonatal characteristics of 126 neonates born to mothers with syphilis_

CharacteristicsCase (N = 40)Control (N = 86)Total (N = 126)

n (%)n (%)n (%)
Maternal characteristics
Age (years)
  <2017 (42.5)30 (34.9)47 (37.3)
  20–3419 (47.5)45 (52.3)64 (50.8)
  ≥354 (10.0)11 (12.8)15 (11.9)
Median (IQR)20 (18–22.5)21 (18–25)20 (18–24)
Ethnicity
  Thai37 (92.5)82 (95.3)119 (94.4)
  Others3 (7.5)4 (4.7)7 (5.6)
Education (n = 60)
  Primary school3 (33.3)16 (31.4)19 (31.7)
  Secondary school6 (66.7)33 (64.7)39 (65.0)
  Bachelor degree or higher0 (0.0)2 (3.9)2 (3.3)
Maternal co-infection
  HIV2 (5.0)2 (2.3)4 (3.2)
  Hepatitis B1 (2.5)1 (1.2)2 (1.6)
Antenatal care
  Yes36 (90.0)79 (91.9)115 (91.3)
  No4 (10.0)7 (8.1)11 (8.7)
Maternal treatment
  Adequate14 (35.0)51 (59.3)65 (51.6)
  Inadequate13 (32.5)17 (19.8)30 (23.8)
  No treatment13 (32.5)18 (20.9)31 (24.6)
Mode of delivery
  Vaginal31 (77.5)57 (66.3)88 (69.8)
  Cesarean section9 (22.5)26 (30.2)35 (27.8)
  Vacuum extraction0 (0.0)3 (3.5)3 (2.4)
Neonatal characteristics
Sex: Male22 (55.0)39 (45.3)61 (48.4)
Gestational age (weeks)
  <3713 (32.5)10 (11.6)24 (19.0)
  37–4227 (67.5)74 (86.0)100 (79.4)
  >420 (0.0)2 (2.3)2 (1.6)
  mean ± SD37.05 ± 2.8138.02 ± 2.3637.73 ± 2.55
Birth weight (grams)
  <10001 (2.5%)0 (0.0%)1 (0.8%)
  1001–15001 (2.5%)1 (1.2%)2 (1.6%)
  1501–20003 (7.5%)4 (4.7%)7 (5.6%)
  2001–25007 (17.5%)8 (9.3%)15 (11.9%)
  >250028 (70.0%)73 (84.9%)101 (80.2)
  mean ± SD2753.98 ± 680.872882.78 ± 490.162841.89 ± 558.24
Low birth weight (<2500 grams)
  Yes12 (30.0%)13 (15.1%)25 (19.8%)
  No28 (70.0%)73 (84.9%)101 (80.2%)
Birth weight for GA
  SGA2 (5.0%)3 (3.5%)5 (4.0%)
  AGA37 (92.5%)81 (94.2%)118 (93.7%)
  LGA1 (2.5%)2 (2.3%)3 (2.4%)
Birth asphyxia
  No34 (85.5%)78 (90.7%)112 (88.9%)
  Yes6 (15.0%)8 (9.3%)14 (11.1%)

Univariable and multivariable analysis for factors associated with congenital syphilis in neonates born to mothers with syphilis_

CharacteristicsCase (N = 40)Control (N = 86)OR95% CIPOR95% CIP
Maternal Age, years
  <2019 (47.5%)30 (24.9%)1.00Reference
  20–3417 (42.5%)45 (52.3%)1.340.60–2.990.472
  ≥354 (10.0%)11 (12.8%)0.860.24–3.050.817
1st ANC visit
  1st trimester10 (25%)32 (37.2%)1.00Reference
  2nd or 3rd trimester26 (65%)47 (54.7%)1.770.75–4.170.191
  No ANC4 (10%)7 (8.1%)1.830.44–7.560.404
Maternal RPR before delivery
  <1:814 (35.0%)48 (55.8%)1Reference 1.0Reference
  >1:823 (57.7%)32 (37.2%)2.461.11–5.490.0272.010.87–4.680.105
  Non-reactive3 (7.5%)6 (7.0%)1.710.38–7.750.4841.010.19–5.300.989
Maternal treatment
  Adequate14 (35.0%)51 (59.3%)1.00Reference 1.0Reference
  Inadequate13 (32.5%)17 (19.8%)2.791.10–7.080.0312.691.02–7.110.046
  No treatment13 (32.5%)18 (20.9%)2.631.04–6.650.0411.840.65–5.170.248
Mode of delivery
  Cesarean section/vacuum extraction9 (22.5%)29 (33.7%)1.00Reference
  Vaginal31 (77.5%)57 (66.3%)1.750.74–4.170.204
Preterm birth
  No27 (67.5%)76 (88.4%)1.00Reference 1.0Reference
  Yes13 (32.5%)10 (11.6%)3.661.44–9.310.0062.911.01–8.390.049
Birth weight
  >2,500 g28 (70%)73 (84.9%)1.00Reference
  <2,500 g12 (30%)13 (15.1%)2.410.98–5.900.56

Total live births, neonates born to mothers with syphilis and number of neonates diagnosed with congenital syphilis by year of birth_

Year of birthTotal live birthsNumber of neonates born to mothers with syphilis (%)Neonates diagnosed with congenital syphilisRate of congenital syphilis transmission (%)Incidence of congenital syphilis per 100,000 live births
20113,0706 (0.2)233.365.14
20122,9454 (1.3)125.033.95
20132,6646 (0.2)233.375.08
20142,5348 (0.3)562.5197.32
20152,1549 (0.4)666.7278.55
20162,11533 (1.5)927.3425.53
20172,06434 (1.6)720.5339.14
20182,01226 (1.3)830.8397.61
Total19,558126 (0.6)4031.7204.52
DOI: https://doi.org/10.2478/abm-2023-0039 | Journal eISSN: 1875-855X | Journal ISSN: 1905-7415
Language: English
Page range: 13 - 21
Published on: Aug 7, 2023
Published by: Chulalongkorn University
In partnership with: Paradigm Publishing Services
Publication frequency: 6 issues per year

© 2023 Pimchanok Kulsirichawaroj, Dissajee Lumbiganon, published by Chulalongkorn University
This work is licensed under the Creative Commons Attribution 4.0 License.