Nahlen 1989 NGA.

Methods	Trial design: RCT Data collected: from January to June 1988 Length of follow‐up: 77 days (mean interval from day 7 post‐chloroquine treatment to documentation of parasitaemia was 74 days for pyrimethamine group) Frequency of follow‐up: weekly. Follow‐up examinations and blood smears were obtained on days 2, 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, and 77
Participants	Parity: all Number: 71 Inclusion criteria: antenatal and attending hospital and health centre; < 34 weeks gestation; no recent chloroquine taken; parasitaemic > 500 parasites/µL blood Excluded: history of antimalarial drug ingestion during the previous week
Interventions	Pyrimethamine (25 mg): weekly Nothing Other: treated with two doses of chloroquine at recruitment; folic acid and iron given to all women Administration supervised: yes
Outcomes	Antenatal parasitaemia
Notes	Location: Nigeria Urban/rural: urban (Ilorin, the capital of Kwara State) Malaria transmission: endemic area Drug resistance: possible pyrimethamine resistance present Funding: US Agency for International Development, Africa Child Survival‐Initiative‐Combatting Childhood Communicable Diseases Project, 698‐0421
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Women in group 2 were assigned randomly to a pyrimethamine treatment or a control group." The statement that women were randomly assigned is insufficient to be confident that the allocation sequence was genuinely randomized.
Allocation concealment (selection bias)	High risk	"The treated group was observed to take 25 mg of pyrimethamine weekly and was instructed to take folic acid and iron supplements daily, while the control group took only folic acid and iron daily." Allocation not concealed.
Blinding (performance bias and detection bias) All outcomes	High risk	Not blinded.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details provided.
Incomplete outcome data (attrition bias) All outcomes	Low risk	"In vivo tests were completed successfully in all 71 women enrolled." Comment: There were no missing outcome data.
Selective reporting (reporting bias)	Low risk	No apparent risk.
Other bias	Low risk	None identified.