Study	Reason for exclusion
Alcalay 1996	PROM at term
Amano 1999	Alternate allocation trial
Ascher‐Walsh 2000	Compared 2 forms of IOL
Bell 1993	Trial of cervical ripening not IOL
Berghella 1996	Membrane stripping to decrease the need for formal IOL
Boulvain 1998	Membrane stripping to decrease the need for formal IOL
Buttino 1990	Trial of cervical ripening not IOL
Cardozo 1986	Alternate allocation trial
Conway 2000	Trial of active versus expectant management in women with oligohydramnios
CTRI/2018/09/015719	High‐risk pregnancy (women with previous caesarean) included in this trial
Damania 1992	Trial of cervical ripening (2 methods) not IOL
Dare 2002	Trial of cervical ripening not IOL
De Aquino 2003	Compares 2 forms of IOL
Doany 1997	Trial of cervical ripening not IOL
Dunn 1989	Intervention not a policy to induce labour compared with expectant management
El‐Torkey 1992	Trial of cervical ripening not IOL
Elliott 1984	Trial of nipple stimulation as a method of cervical ripening. No commitment to delivery within a given time or protocol
Evans 1983	Compares 2 forms of IOL
Frass 2011	Trial where all women were judged to be at risk (severe pre‐eclampsia)
Garry 2000	Alternate allocation trial
Giacalone 1998	Trial of cervical ripening not IOL
Gregson 2015	Assessing effectiveness of acupuncture for IOL (role of acupuncture not established)
Hage 1993	Trial of cervical ripening not IOL
Heden 1991	Alternate allocation trial
Hernandez‐Castro 2008	Not a RCT
Imsuwan 1999	This is a RCT evaluating the effectiveness of weekly membrane sweeping in labour initiation for women at 41 completed weeks. It is not evaluating a policy of stopping the pregnancy at 41 weeks
Ingemarsson 1987	Trial of cervical ripening not IOL
Iqbal 2004	Alternate allocation trial
Jenssen 1977	Trial of cervical ripening not IOL
Kadar 1990	Trial of nipple stimulation as a method of cervical ripening. No commitment to delivery within a given time or protocol
Katz 1983	Alternate allocation trial
Kipikasa 2005	Comparing alternate methods for IOL
Klopper 1969	Trial of cervical ripening not IOL
Knox 1979	Quasi‐randomised (last digit of hospital number)
Lee 1997	Compares 2 forms of IOL
Lemancewicz 1999	Compares 2 forms of IOL
Lien 1998	Trial of cervical ripening not IOL
Lyons 2001	Trial of cervical ripening not IOL
Magann 1998	Trial of cervical ripening not IOL
Magann 1999	Compares 2 forms of IOL
Mancuso 1998	Compares 2 forms of IOL
Meydanli 2003	Compares 2 forms of IOL
Misra 1994	Compares 2 forms of IOL
Müller 1995	Compares 2 forms of IOL
Neri 2014	Assessing effectiveness of acupressure for IOL (role of acupuressure not established)
Newman 1997	Trial of cervical ripening not IOL
Nicholson 2008	Trial where all women were judged to be at risk
Ohel 1996	Alternate allocation
PACTR201805002872322	Not low risk pregnancies
Papageorgiou 1992	Compared 2 forms of IOL
Paul 1988	Protocol for RCT only ‐ no results
Rayburn 1988	Trial of cervical ripening not IOL
Rayburn 1999	Trial of cervical ripening not IOL
Rijnders 2011	Compared 2 alternative management strategies for IOL
Roberts 1986	Trial of cervical ripening not IOL
Satin 1991	Compared 2 forms of IOL
Sawai 1991	Trial of cervical ripening not IOL
Sawai 1994	Trial of cervical ripening not IOL
Stenlund 1999	Mifepristone versus placebo for IOL, but all women given PGE2 if necessary after 48 hours
Su 1996	Both groups induced within 2 days with alternative methods
Surbek 1997	Compared 2 forms of IOL
Suzuki 1999	Immediate IOL versus expectant management in twin pregnancies
Williams 1990	Trial of cervical ripening not IOL
Wing 2000	Trial of cervical ripening not IOL
Wong 2002	Trial of cervical ripening not IOL
Ziaei 2003	Trial of cervical ripening not IOL

IOL: induction of labour
PGE2: prostaglandin E2
PROM: premature rupture of membranes
RCT: randomised controlled trial