Hydralazine (versus unexposed)

Study	Type of data	Exposure measurement	Outcome assessment	Adjustment
Welt, 1981	randomized controlled trial	Pregnant women were randomly and blindly assigned to 1 of 3 drug groups.	Patients were seen intensively (twice monthly then weekly from the 30th week of gestation) during pregnancy, until delivery.	No adjustment. Randomisation. Exclusion of patients with insulin-requring diabetes or multiple pregnancies.