Italy 1999.

Methods	Allocation concealment: consecutive‐numbered, opaque, sealed envelopes. 3‐arm study. 6 women (17%) left the study due to side‐effects (2 women) or mother's or baby's worsening conditions (4). Three arms
Participants	36 women with singleton pregnancy, gestation > 24 weeks and PIH or PE (BP 140/90 mmHg or more, PE if proteinuria > 300 mg/24 hr). Excluded: fetal abnormalities or chromosomal disorders, renal or hepatic disease, chronic HT.
Interventions	Exp (1): transdermal GTN 10 mg continuously 24 hr/day (12 women). Exp (2): transdermal GTN 10 mg intermittently for 16 hrs/day.(12 women) Control: oral nifedipine 40 mg/day orally. (12 women)
Outcomes	Women: caesarean section, BP (mean), stopped drug due to side‐effects, severe HT, proteinuria/PE. Babies: birthweight, fetal/neonatal deaths, preterm birth, IUGR, gestation at birth (mean).
Notes	Korotkoff phase IV used for DBP. In the analysis the 2 GTN arms have been combined. Additional data provided by authors. 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)	Low risk	Consecutive opaque sealed envelopes (personal communication).
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	High risk	6 withdrawals (16.6%). 3 in group 1, 1 in group 2 and 2 in group 3.
Selective reporting (reporting bias)	Low risk	Additional data provided by authors.
Other bias	Unclear risk	No information about funding source. Declaration of interests not described.