USA 1979.

Methods	Allocation concealment: not stated. Authors state: "allocated randomly to treatment or no treatment". Two arms
Participants	58 women with HT before pregnancy or BP >/= 140/90 mmHg x 2 more than 24 hrs apart before 20 weeks' gestation. Excluded: DBP > 100 mmHg, nulliparous, other major medical or obstetric problem.
Interventions	Exp: oral methyldopa 750 mg/day to 2000 mg/day, oral hydrochlorothiazide 50 mg/day, oral hydralazine 75 mg/day to 250 mg/day. (29 women) Control: no antihypertensive. (29 women)
Outcomes	Women: severe HT, proteinuria (> 1+ or > 300 mg/L in 24 hrs), caesarean section. Babies: perinatal death, gestation at delivery, birthweight < 2500 g, fetal distress, SGA (undefined).
Notes	No information about how BP measured. In exp group, 11 women had methyldopa + hydrochlorothiazide, 10 hydralazine + hydrochlorothiazide, 8 had all 3 drugs. Funding: no information about funding source. Declaration of interests not described.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described.
Allocation concealment (selection bias)	Unclear risk	Not described. Quote: "...allocated randomly to treatment or no treatment...". No further details.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Open‐label trial.
Blinding of outcome assessment (detection bias) All outcomes	High risk	No.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No.
Selective reporting (reporting bias)	Unclear risk	Assessment from published study report.
Other bias	Unclear risk	Groups appear comparable at baseline. No information about funding source. Declaration of interests not described.