Case Study Reports: Antenatal Screening

ANTENATAL SCREENING

History

A 31-year-old pregnant Russian woman came to the UK 6 weeks ago with her English husband. As a result she booked late with the midwife at 31 weeks’ gestation. This is her first ongoing pregnancy, having had two uncomplicated surgical terminations approxi- mately 10 years ago. She reports a history of genital herpes diagnosed by her general practitioner several weeks ago. There is no relevant previous general medical history or family history.

She had an apparently normal first-trimester scan in Russia before arriving in the UK and has had a normal anomaly scan in this hospital at 30 weeks’ gestation.

Examination

Blood pressure is normal and symphysiofundal height is consistent with menstrual dates.

Questions

·             What is the diagnosis?

·              How should the woman be further investigated and treated?

ANSWER

Screening for syphilis is recommended for all pregnant women and T. pallidum EIA is a specific test for syphilis infection. The prevalence of infection is up to 0.3/1000 pregnant women in the UK. EIA tests that detect immunoglobulin G (IgG) or IgG and IgM, T. pal- lidum haemagglutination test and the fluorescent treponemal antibody-absorbed test (FTA-abs) are used generally for screening in pregnancy, as they are 98 per cent sensitive and over 99 per cent specific.

In cases with a positive screening test a second treponemal-specific confirmatory test should be sent to confirm the diagnosis. Caution is needed as treponemal-specific tests cannot differentiate syphilis from other treponemal disease (yaws, pinta and bejel).

The diagnosis in this woman is syphilis infection. She should be referred to a genito- urinary medicine clinic for urgent assessment and treatment. She may have a genital ulcer (possibly misdiagnosed as herpes simplex by her doctor) or features of secondary syphilis, but many women diagnosed are asymptomatic (latent syphilis).

Management

Treatment is with intramuscular penicillin daily for 10 days (doxycycline or erythromycin if penicillin allergic). Follow-up with a quantitative test (such as venereal disease research laboratory [VDRL] should be used to confirm effective treatment and to monitor for reinfection. The woman’s partner should be referred to the genitourinary medicine clinic for testing (45–60 per cent of partners will be infected).

The paediatricians should be informed at delivery to assess for signs of early congenital syphilis (usually developing in the first few weeks of life) and to arrange serological testing.

Untreated, 70–100 per cent of babies of mothers with syphilis infection will develop con- genital syphilis, with a 30 per cent stillbirth rate.