USA ‐ Tennessee 2001.

Methods	Please see details below.
Participants	222 women with mild pre‐eclampsia during labour. Excluded: chronic HT, severe PE.
Interventions	MgSO4: 6 g IV, then infusion of 2 g/hr. Placebo: matching regimen. Clinical monitoring.
Outcomes	Women: progression to severe PE, eclampsia, HELLP, caesarean section, toxicity. Baby: meconium.
Notes	Abstract only. 33 women who progressed to severe pre‐eclampsia were unblinded and given MgSO4.
Risk of bias
Bias	Authors' judgement	Support for judgement
Adequate sequence generation?	Low risk	Computer generated group assignment was devised by simple randomisation sequence.
Allocation concealment?	Low risk	"Sealed, consecutively numbered, opaque envelopes."
Blinding? All outcomes	Low risk	Designed as a double blind study, but if the woman developed severe pre‐eclampsia after randomisation, group assignment was revealed. If the woman had been assigned to placebo, she was subsequently treated with magnesium. Data were collected by blinded chart abstraction, except for women who developed severe pre‐eclampsia after randomisation, data collection was unblinded in that circumstance.
Incomplete outcome data addressed? All outcomes	High risk	Published as abstract only, there is no information about other outcome data collected but not reported.