Comparison 1. Oestrogen versus placebo: all women.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
2 Uterine hyperstimulation with FHR changes	1	25	Risk Ratio (M‐H, Fixed, 95% CI)	3.44 [0.18, 64.88]
3 Caesarean section	5	306	Risk Ratio (M‐H, Fixed, 95% CI)	1.00 [0.60, 1.68]
4 Serious neonatal morbidity or perinatal death	2	75	Risk Ratio (M‐H, Fixed, 95% CI)	1.0 [0.07, 15.12]
7 Oxytocin augmentation	1	87	Risk Ratio (M‐H, Fixed, 95% CI)	0.93 [0.61, 1.43]
8 Uterine hyperstimulation without FHR changes	1	25	Risk Ratio (M‐H, Fixed, 95% CI)	0.0 [0.0, 0.0]
11 Instrumental vaginal delivery	3	162	Risk Ratio (M‐H, Fixed, 95% CI)	0.75 [0.46, 1.22]
12 Meconium stained liquor	1	87	Risk Ratio (M‐H, Fixed, 95% CI)	0.49 [0.13, 1.83]
14 Neonatal intensive care unit admission	1	87	Risk Ratio (M‐H, Fixed, 95% CI)	0.98 [0.06, 15.13]
16 Perinatal death	2	75	Risk Ratio (M‐H, Fixed, 95% CI)	0.33 [0.01, 7.81]
20 Serious maternal complications	1	87	Risk Ratio (M‐H, Fixed, 95% CI)	2.93 [0.85, 10.10]