“…All the studies were performed in gynecological or maternal units at public or private hospitals. Recruitment was performed by inviting consecutive women attending the clinic in approximately half of the cases (n = 25/43) [2,20,[24][25][26]29,30,33,35,[37][38][39][40]42,44,46,47,49,[51][52][53][54]56,60,61], random sampling was employed in four studies (n = 4), antenatal care registry was used in three studies (n = 3) [21,36,59], convenience sampling was adopted in other three studies (n = 3) [27,28,32], multistage sampling approach was used in two studies (n = 2) [55,58], the snow-ball method was used in one study (n = 1) [22], and one study used data from an ongoing prospective longitudinal cohort study (n = 1) [50]. Four studies did not specify the recruitment method adopted [23,31,45,48].…”