WHO 1976.

Methods	Computer‐generated randomisation table. Identity of the compound was kept in a sealed envelope until the patient was accepted for the study.
Participants	1513 pregnant women (group I: 717, group II: 796) Inclusion criteria: 13‐22 weeks of gestation. Exclusion criteria: previous heart disease, hypertension, respiratory disease, ulcerative colitis, diabetes mellitus, disorders of blood coagulation, kidney disease, liver disease, sickle‐cell anaemia, severe hypersensitivity, serious systemic disease, contraindication to transperitoneal uterine puncture (previous abdominal surgery on the body of the uterus, large uterine myomata/pelvic tumors, major congenital abnormalities of the uterus, rupture of membranes, earlier failed saline induction).
Interventions	Both groups were punctured with a fine‐bore needle and a small amount of amniotic fluid withdrawn to confirm the intra‐amniotic position. Group I: 200 mL 20% saline was slowly injected, intra‐amniotic; Group II: 5 mL tromethamine salt of PGF2α (= 25mg PGF2α) was injected, intra‐amniotic. A catheter was left in position and 6h later a second injection op 25mg PGF2α was given.
Outcomes	Abortion interval, complications, side‐effects.
Notes	Definition of abortion: spontaneous expulsion of placenta through the cervix into the vagina. If the placenta was incomplete, evacuation of the uterus was performed. Re‐admission to hospital was necessary for 17 patients given PGF2α and 13 patients given saline (excessive blood loss, retained products of conception, signs of genital tract infection).
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Low risk	A ‐ adequate
Blinding? All outcomes	High risk
Free of other bias?	Low risk	No apparant differences between the groups in terms of maternal age, gestational age and parity.