All women in the trial received three tablets of SP (25 mg pyrimethamine and 500 mg sulfadoxine) (Cosmos Pharmaceutical, Nairobi) given under observation. Women in the 'early' folic acid group then received a packet containing Fefol (500 ug of folic acid and 47 mg of ferrous sulfate) to be taken at home once per day for 14 days. Women in the 'late' folic acid group received packets containing oral iron (60 mg/day) alone to be taken daily for 14 days. At the day 14 follow-up they then received iron and folic acid so no woman was deprived of folic acid supplementation.