Syphilis
Warning
- All pregnant women should have serological testing for syphilis at their first antenatal assessment. Tests should be repeated later in pregnancy if a woman has been at risk of infection after a negative initial screen.
- In the UK in 2011 approximately 0.15% of women had a positive antenatal test. Of these:
- 46% had been adequately treated for syphilis before conception
- 23% had false positive tests
- 21% were diagnosed and required treatment for the first time during the current pregnancy
- Although fetal infection usually occurs late in pregnancy it has been demonstrated as early as 8-9 weeks of gestation. This may result in polyhydramnios, miscarriage, preterm labour, still birth and hydrops.
- In untreated early syphilis 70-100% of infants will be infected, with still births occurring in up to one third of cases.
- Ten percent of infants born to mothers with late infection will be affected.
- Babies born with congenital syphilis can have early manifestations of the disease (within the first 2 years of life) or late manifestations (after 2 years of life) including the stigmata of congenital syphilis.
- Syphilis in pregnancy should be managed as clinically urgent and requires a multi disciplinary approach between sexual health, obstetrics and fetal medicine/paediatrics.
- It has to be clearly established who is the Sexual Health clinician responsible for coordinating the treatment of the pregnant women and who has responsibility for
liaising with the neonatologist. - Where syphilis was cured prior to current pregnancy the RPR/VDRL titres should be checked at the first antenatal booking appointment and repeated at 28 weeks gestation. If the RPR/VDRL excludes reinfection and there is no ongoing risk of infection, the women requires no further treatment and there is no need for the neonate to undergo tests for syphilis.
- Retreatment of women with a history of syphilis treated before conception should be considered when
- There is uncertainty about the adequacy of treatment based on history
- Serological cure (i.e. a 4 fold drop in RPR/VDRL titre) did not occur.
- A pregnant woman’s treatment should be appropriate for the stage of syphilis diagnosed (see BASHH Syphilis Guideline) with comprehensive follow up to minimise the likelihood of her developing long term complications of untreated/inadequately treated syphilis.
- If treating early syphilis in the third trimester a second dose of benzathine penicillin should be given one week later due to lower serum levels of the drug and risk of treatment failure
- Treatment with macrolides is no longer a treatment option as it may result in treatment failure and transmission to neonate. For pregnant women who report intolerance or allergy to penicillin or other beta-lactam antibiotics please refer to the detailed BASHH Syphilis Guideline and consult with senior colleagues.
- The Jarisch-Herxheimer reaction may occur just as in non pregnant women. This may cause uterine contractions and fetal heart rate decelerations, as a result of maternal fever. There is a theoretical increased risk of spontaneous and iatrogenic preterm delivery and fetal demise associated with the reaction, though these complications are also associated with syphilis infection. Management should be supportive and include antipyretics. Steroids are not effective in reducing these effects.
- Additional fetal scanning and monitoring may be indicated. This should be discussed by the multi-disciplinary team.
- All children born to mothers with positive serology require referral to fetal medicine/paediatricians for clinical evaluation and syphilis serology tests, with the following exceptions
- maternal biological false positive serology
- maternal syphilis cured prior to this pregnancy
- Treatment for congenital syphilis is needed in infants
- born to mothers treated less than 4 weeks prior to delivery
- suspected of having congenital syphilis
- born to mothers treated with non penicillin regimens
- born to mothers without documented evidence of adequate treatment
- Partner notification is essential to reduce the possibility of re-infection of a pregnant woman (and unborn child). Untested older siblings may need testing for syphilis.