A retrospective national epidemiological Swiss study was conducted to establish a real prevalence and description of congenital syphilis, and to better classify the reported congenital syphilis.

Maternal risk factors to contract syphilis (i.e. socio-demographic, cultural and clinical factors) were also evaluated, in order to focus on prevention of these targeted population.

Follow up of the children born from mother with syphilis during pregnancy, until age 6, was recorded to evaluate the risk of congenital syphilis following treatment of maternal syphilis.

We conducted an observational and descriptive retrospective multicentric national study in Switzerland of all pregnant women diagnosed with syphilis during their pregnancy and their babies from childbirth to age 6.

Retrospective clinical and biological data already collected in the patient's medical file from 2012 until 2021 were collected from pregnant women diagnosed with syphilis during their pregnancy and their babies from childbirth to age 6, in Swiss universities and cantonal hospitals.

Cases were collected through the computerized laboratory records by selecting all pregnant women with a positive TPHA / TPPA serology and children born to mothers who had syphilis diagnosed during pregnancy or / and with a positive TPHA / TPPA serology. Data collected included clinical information's, results of biological tests and imagery available from the hospital's internal archiving system and registered on two standardized coded case report forms (one for the mother and one for the babies).

Recent guidelines from the Centers for Disease Control recommend testing for syphilis at the first prenatal visit and again at 28 weeks gestation and at delivery if at high risk for syphilis acquisition during pregnancy. The identification, through the collection of epidemiological data, of risk factors for developing congenital syphilis during pregnancy may improve the prevention of congenital syphilis in the population at risk. It would make it possible to carry out preventive actions, repeated screening of syphilis during pregnancy and closer monitoring in a targeted population of women of childbearing age.

Thus, a proactive sentinel network could be developed to limit new cases of congenital syphilis in Switzerland, with the development of tools that could send alerts to the various specialists involved (biologist, gynaecologist, paediatrician, dermatologist) when a syphilis serology comes back positive in a pregnant woman.

This project is part of one of WHO's goals to eradicate congenital syphilis, as a better knowledge of congenital syphilis could lead us to propose solutions intended to reduce this serious disease. All the more that congenital syphilis is preventable by syphilis pregnancy screening and the burden of congenital syphilis is avoidable with a simple cost-effective treatment.

Inclusion Criteria:

• All pregnant women who had a positive TPHA / TPPA serology during pregnancy.
• All children born to mothers who had syphilis diagnosed during pregnancy or / and with a positive TPHA / TPPA serology.

Exclusion Criteria:

• Document in the medical file attesting to a refusal of consent to the re-use of the data

All pregnant women with a positive syphilis screening and their babies until age 6 from university and cantonal hospitals in Switzerland (Geneva, Lausanne, Zurich, Bern, Basel, Saint Gallen, Valais, Lugano) in dermatology, paediatric and gynaecology wards.

Retrospective analysis of data from medical records.