Syphilis intervention in pregnancy: Zambian demonstration project
Objective: Despite availability of simpler serologic tests for syphilis and near cure with penicillin, unacceptably high prevalence of infectious maternal syphilis exist in many developing countries, including Zambia. It is the foremost risk factor for mid-trimester abortions, stillbirths, prematurity and morbidity and mortality among infants born with congenital syphilis in Zambia.
Methods: An intervention project was conducted in Lusaka aimed at demonstrating the effectiveness of new health education methods and prenatal screening for syphilis in reducing the adverse outcomes during pregnancy. During pre-intervention phase, approximately 150 consecutive pregnant women from each of the three study and the three control centres were recruited when they presented in labour at the University Teaching Hospital. The intervention phase lasted for one year at the three study centres during which new methods of health education were introduced to improve early attendances during pregnancy. Also, on-site syphilis screening was performed twice during pregnancy and seroreactive women, and in many cases their sexual partners, were treated by the existing prenatal clinic staff. During the post-intervention phase the steps of pre-intervention phase were repeated to evaluate the impact of intervention.
Results: Overall, 8.0% of women were confirmed seroreactive for syphilis; there was no difference between the study and the control centres (p > 0.05). Fifty seven percent (132/230) of syphilitic pregnancies ended with an adverse outcome, that is, abortion (RR 5.0), stillbirth (RR 3.6), prematurity (RR 2.6) and low birth weight (RR 7.8). The overall risk of adverse outcomes outcomes due to syphilis was 8.29 (95% confidence interval 6.53, 10.53). The new methods of health education were effective and the percentage of women who had their first prenatal visit under 16 weeks of gestation improved from 9.4 to 42.5. Although screening and treatment during intervention was suboptimal, the adverse outcomes attributable to syphilis were reduced to 28.3%; this is almost a two-third reduction when compared with 72.4% of adverse outcomes at control centres (p > 0.001). The intervention is culturally and politically acceptable in Zambia. The cost of each prenatal screening is US$o.60 and of averting each adverse outcome US$12. In countries with high rates of syphilis, there is an urgent need for STD control and Maternal and Child Health (MCH) programmes to pool their resources together to revitalise the prenatal care. Researchers at the University Teaching Hospital in Lusaka, Zambia implemented their syphilis intervention project in 3 phases: preintervention phase (September 1985-January 1986), intervention phase (February 1986-January 1987), and postintervention phase (February-June 1987). To evaluated the effectiveness of the project, they followed 491 women from 3 periurban health centers serving as study centers and 434 from 3 similar control centers. 8% of all women tested positive for syphilis which was lower than seroprevalence for prenatal patients in 1980 and 1983 (12.5% and 12.8% respectively). Before intervention, 9.4% of the women visited a health center for the 1st prenatal visit before 16 weeks gestation. Following health education during the intervention phase, this percentage climbed to 42.5%. Health workers conducted a syphilis test on 58.6% and 14.3% of the women during their 1st visit to a study center and control center respectively. Prior to intervention, adverse outcomes occurred in 58% of syphilitic pregnancies. Total relative risk (RR) for adverse outcomes stood at 8.29. Specifically, RR was 7.76 for low birth weight, 5.03 for abortion, 3.57 for stillbirth, and 2.61 for premature birth. 2.2% of the syphilitic pregnancies resulted in congenital syphilis. Before penicillin was available for treatment these percentages were 20-40% abortions, 20-30% stillbirths, and 25% congenital infections. After the intervention phase, syphilitic pregnancies resulted in 28.3% adverse outcomes (p.001). The percentage of adverse outcomes at the control centers stood at 72.4%. Further, nonsyphilitic pregnancies resulted in 11.1% adverse outcomes before intervention and 8.1% following intervention (p.05). This study showed that syphilis intervention is effective and not costly (US$12 to prevent each adverse outcome).