Table 1

Characteristics of included studies

Author	Year	Country	Study design	Number of cases	Number of hospital units	Year of data collection	Population	Sampling	Type of CS analysed	National CS rates*
Braveman et al	1995	USA	Retrospective cohort study	213 761	Unclear	1991	Primiparae; no previous CS; any risk	Consecutive	Any	High
Naiditch et al	1997	France	Cross-sectional	39 880	944	1991	Primiparae and multiparae; no previous CS; any risk	Random	Before labour	Moderate
Gomes et al. A	1999	Brazil	Cross-sectional	6750	8	1978–1979	Primiparae and multiparae; with or without previous CS; any risk	Consecutive	Any	Very high
Gomes et al. B	1999	Brazil	Cross-sectional	2846	10	1994	Primiparae and multiparae; with or without previous CS; any risk	Consecutive	Any	Very high
Gonzalez-Perez et al	2001	Mexico	Cross-sectional	1 716 446	Unclear	1994–1997	Primiparae and multiparae; with or without previous CS; any risk	Consecutive	Any	High
Korst et al	2005	USA	Cross-sectional	443 532	288	1995	Primiparae and multiparae; no previous CS; any risk	Consecutive	During labour	High
Mossialos et al.	2005	Greece	Cross-sectional	805	3	2002	Primiparae and multiparae; with or without previous CS; any risk	Consecutive	Any	High
Carayol et al A	2007	France	Cross-sectional	1479	Unclear	1972, 1995, 1998, 2003	Primiparae and multiparae; no previous CS; high risk	Random	Before labour	Moderate
Carayol et al B	2007	France	Cross-sectional	6080	138	2001-2002	Primiparae and multiparae; no previous CS; high risk	Random	Before labour	Moderate
Xirasagar and Lin	2007	Taiwan	Cross-sectional	739 531	942	1997–2000	Primiparae and multiparae; with or without previous CS; any risk	Consecutive	Before labour†	High
Coonrod et al	2008	USA	Cross-sectional	28 863	40	2005	Primiparae; low risk	Consecutive	Any	High
Coulm et al	2012	France	Cross-sectional	9530	535	2010	Primiparae and multiparae; no previous CS; low risk	Consecutive	Any	Moderate
Huesch et al	2014	USA	Cross-sectional	408 355	254	2010	Primiparae and multiparae; no previous CS; any risk	Consecutive	Before labour	High
Raifman et al A	2014	Brazil	Cross sectional	4918	Not Reported	1996	Primi- and multiparae; with or without previous CS; any risk	Random	Any	Very high
Raifman et al B	2014	Brazil	Cross sectional	5768	Not Reported	2006	Primi- and multiparae; with or without previous CS; any risk	Random	Any	Very high
Schemann et al	2015	Australia	Cross sectional	61 894	81	2007-2011	Multiparae; with previous CS	Consecutive	Any	High
Sebastião et al	2016	USA	Retrospective cohort study	412 192	122	2004-2011	Primiparae; low risk	Consecutive	During labour	High

*National CS rates classified according to WHO data reported for 2008 into moderate (>15% to 20%), high (>20% to 40%) and very high (>40%).
†On maternal request.
CS, caesarean section.