Sulfadoxine/pyrimethamine protects pregnant women against malaria, STIs

Intermittent preventive treatment with sulfadoxine/pyrimethamine appeared to protect against malaria, sexually transmitted infections and reproductive tract infections, as well as other causes of adverse birth outcomes, among pregnant Zambian women, study data showed.

“To reduce the adverse consequences of malaria infection during pregnancy, [WHO] recommends administering sulfadoxine/pyrimethamine as intermittent preventive treatment to women during every scheduled antenatal care visit at least 1 month apart during the second trimester and at delivery in areas of moderate to high malaria transmission,” R. Matthew Chico, MPH, assistant professor in the department of disease control at the London School of Hygiene & Tropical Medicine, and colleagues wrote. “Although the WHO recommendation … does not extend to low-transmission settings, a recent metaregression analysis suggests there is not a threshold of malaria transmission intensity below which at least two doses of intermittent preventive treatment with sulfadoxine/pyrimethamine are no longer protective against the incidence of low birth-weight in Sub-Saharan Africa.”

The researchers performed a prospective cohort study with 1,086 women living in the Nchelenge District of Zambia between November 2013 and April 2014, recruiting participants on their first visits to Ministry of Health centers for antenatal care. Chico and colleagues calculated the ORs of adverse birth outcomes among women who had zero to one dose (n = 126) vs. two or more doses (n = 590), and two doses (n = 310) vs. three or more doses (n = 280), across multiple categories of infection, including malaria, STIs and reproductive tract infections.

Chico and colleagues said they found no difference in the incidence of infections across groups, but that women who had two doses experienced a 45% reduction in the odds of adverse birth outcomes compared with those who had 0 to 1 dose (OR = 0.55; 95% CI, 0.36-0.86). Those who had at least three doses saw an additional 13% reduction (OR = 0.43; 95% CI, 0.27-0.68).

Two doses of preventive treatment resulted in a 58% reduction in preterm delivery compared with zero to one dose, the researchers reported (OR = 0.42; 95% CI, 0.27-0.67). This fell by a further 21% after at least three doses (OR = 0.21; 95% CI, 0.13-0.35). Women with malaria at enrollment who received two or more doses were 76% less likely to have an adverse birth outcome (OR = 0.24; 95% CI, 0.09-0.66), and women with Neisseria gonorrhoeae and/or Chlamydia trachomatis were 92% less likely to have an adverse birth outcome (OR = 0.08; 95% CI, 0.01-0.64). Patients who received at least two doses and who did not have malaria or any STIs experienced 73% fewer adverse birth outcomes (OR = 0.27; 95% CI, 0.11-0.68).

“To our knowledge, we are the first to investigate the association between the number of intermittent preventive sulfadoxine-pyrimethamine doses and malaria, curable sexually transmitted/reproductive tract infections and birth outcomes,” the researchers wrote. – by Andy Polhamus

Disclosure: The researchers report no relevant financial disclosures.