Table 2. Comparison of the included studies.
Author Year Period Country Outline N cases IVF Case-control Age IVF Age SC Control (PP/CS) RR PAS IVF (CI) PAS Diagnosis Maternal outcome
Zhu et al. 2016 2006–2014 China RC 7923 2641 5282 31 31 cs 2.37 (1.9–2.95) U no
Tanaka et al. 2020 2015–2017 Japan RC 6952 811 6141 37.2 31 X 7.35 (3.2–16.6) U no
Esh-Broder et al. 2011 2004–2009 Israel Cohort 42 12 30 37.8 33.5 yes 13.2 (6.7–25.8) P no
Nagata et al. 2019 2011–2014 Japan Cohort 103099 3147 90506 36 31 CS 6.85 (3.88–12.13) C yes
Modest et al. 2021 2013–2018 USA RC 28344 1418 26926 36.2 32.1 yes 5.5 (3.4–8.7) P yes
Zhang et al. 2024 2018–2021 China RC 47596 3203 41956 31.8 29.4 no 2.72 (2.42–3.07) U no
Wang et al. 2021 2009–2018 China RC 10766 3836 6930 33.4 33.39 * * U no
Violette et al. 2023 X USA RC 96480 48240 48240 35 33 yes 2.06 (1.44–2.93) U no
Lin et al. 2022 2014–2020 China RC 14099 1489 12610 X X CS ** U no
Kong et al. 2022 2013–2018 China RC 16535852 183059 16352793 X X no 2.0 (1.96–2.04) U no
Jiang et al. 2021 2016–2017 China RC 3212 1209 2003 31.8 30.4 no 2.12 (1.42–3.17) P/C no
Al-Khatib et al. 2023 2006–2020 USA RC 240259 2651 237608 X X no 1.66–2.63 U no
Imafuku etal. 2021 2010–2019 Japan RC 4146 579 3566 X X no 4.1 (2.4–7.1) P no

Legend: CS = Cesarean Section; PP = Placenta Previa; SC = spontaneous conception; RC = retrospective cohort; U = unspecified; P = pathological; C = clinical; ART = assisted reproductive technology; FET = frozen embryo transfer.