Screening for syphilis during pregnancy in Nigeria: a practice that must continue.

OBJECTIVE: To determine the seroprevalence rate of syphilis among pregnant women attending the antenatal clinics of a teaching and a state specialist hospital in Nigeria, in order to ascertain whether maternal screening should be incorporated into routine antenatal care of our hospitals.

METHODS: A screening for syphilis for 505 newly registered pregnant women was carried out using the qualitative rapid plasma reagin (RPR) test. All reactive sera were then subjected to the quantitative RPR test to estimate the titre of each sample. The Treponema pallidum haemagglutination antibody (TPHA) test was used as confirmatory test of all positive RPR sera.

RESULTS: A total of 50 women (9.9%) were positive for RPR; 15 (2.97%) were positive for TPHA, giving a seroprevalence rate of 2.97%. A total of 32 women (6.34%) were RPR positive at 1:2, 7 (1.39%) at 1:4 and 11 (2.2%) at 1:8. Of the women positive for RPR at 1:2, 2 were also TPHA positive, 2 of the 7 positive at 1:4 were TPHA positive, while all 11 positive women at 1:8 were TPHA positive. In all, 70% of all RPR positive women screened were biological false positives. Eleven of the 15 women had high titre active syphilis (RPR > or = 1:8, TPHA+) while 4 had low titre active syphilis (RPR <1:8, TPHA+).

CONCLUSIONS: The 2.97% seroprevalence rate obtained after accounting for biological false positives was considered high. Screening for syphilis in pregnancy should be incorporated into routine antenatal practice in Nigerian hospitals.