UK 1989.

Methods	Allocation concealment: drug and placebo sent by manufacturer to hospital pharmacy with list of random numbers. Then dispensed by pharmacists. 5 centres. Withdrawals: 8 (5%), 6 exp, 2 control. 2 women withdrew, 1 treated with ward stock labetalol, 1 developed rash, and 4 did not fulfil entry criteria. Two arms
Participants	152 women from antenatal wards at 20 to 38 weeks' gestation with SBP 140 mmHg to 160 mmHg and DBP 90 mmHg to 105 mmHg x 2, 24 hrs apart, and no proteinuria. Excluded: history of HT, renal, metabolic, cardiovascular, respiratory or collagen disease.
Interventions	Exp: oral labetalol 100 mg x 3/day to 200 mg x 3/day. Control: oral identical placebo.
Outcomes	Women: mean BP, severe HT, proteinuria (undefined), induction of labour, caesarean section, days in hospital (mean), side‐effects. Babies: perinatal death, preterm delivery (< 37 weeks), SGA (< 5th centile), admission to SCBU, RDS.
Notes	Korotkoff phase IV used for DBP. Conventional sphygmomanometers used to measure BP. Funding: funded by industry.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	List of random numbers.
Allocation concealment (selection bias)	Low risk	Drug and placebo sent by manufacturer to hospital pharmacy with list of random numbers. Then dispensed by pharmacists.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind, placebo‐controlled trial.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Yes.
Incomplete outcome data (attrition bias) All outcomes	Low risk	8 women excluded after randomisation (5.3%), without specification of the group they belonged.
Selective reporting (reporting bias)	Unclear risk	Assessment from published study report.
Other bias	High risk	Funded by industry.