Results
In total, 1878 titles and abstracts were screened, 99 potentially relevant studies were examined in detail (Figure 1). 63 prospective studies (two case-control studies, 48 cohort studies, 7 cross-sectional studies, 6 observational studies) reporting data from 6,397,310 women met the inclusion criteria (Appendix S2). All studies reported outcomes comparing planned mode of birth, 36 studies also reported outcomes for emergency CS (57%), 17 studies also reported outcomes for assisted VD, 8 studies reported outcomes for planned VD vs CS for breech birth (13%) (Appendix S2).
Based on the MOMENT score of 4 or more, 37 studies (59%) were of high quality (Appendix S3). The primary outcome was clearly stated in 50 studies (79%), 49 studies (78%) had reproducible primary outcome measures. 11 studies reported secondary outcomes (18%), 6 (10%) studies had reproducible secondary outcome measures. In 51 studies (81%), the authors explained the choice of outcomes selected. 46 studies (73%) employed methods to enhance quality of measures by suitable training, repetition, or adjusting for confounding factors. 3 studies reported composite outcomes studying childhood adverse neurodevelopmental outcome, neonatal morbidity outcomes, and maternal and neonatal complications (Appendix S3) 20-22.
In total, 43 different primary outcomes and 79 different primary outcome measures were identified; 12 different secondary outcomes and 31 secondary outcome measures were identified (Table 2). The most reported outcomes were maternal short-term outcomes (n=26 outcomes), followed by childhood long-term outcomes (n=11 outcomes), neonatal short-term outcomes (n=9), maternal long-term outcomes (n=8), and subsequent pregnancy outcomes (n=1) (Table 2).
The primary outcomes and secondary outcomes were organised into an inventory (Table 3; Table S1 and S2). Maternal primary outcomes were organised into broad categories (Table S1): maternal experiences and feelings (n=11 studies), genitourinary symptoms (n=9), postpartum complications/ morbidity (n=9), maternal experiences and feelings (n=11), breastfeeding (n=5) and hormone levels (n=1). The most reported primary maternal outcomes were breastfeeding (n=5 studies, 8%) and postpartum depression (n=6 studies, 10%). Neonatal outcomes were organised into broad categories: baseline measurements (n=10 studies) and morbidity (n=7). The most reported outcome measurements were baseline measurements such as SpO2, HR, cord blood pH after birth and APGAR score (Table S1). Childhood long-term outcomes were categorised into different health conditions (metabolic diseases, n=4; respiratory, n=4) and neurodevelopmental outcomes (n=9 studies). Two studies looked into maternal subsequent pregnancy outcomes (Table S1).
The secondary maternal outcomes were organised into broad categories (Table S2): genitourinary complications (n=7 studies), maternal experiences and feelings (n=3), maternal morbidities (n=2), breastfeeding (n=2) and baseline measurements (n=1). The most reported outcome was anal and urinary incontinence (n=3). Two studies reported secondary neonatal outcomes and one study reported childhood long-term outcomes. Various scales/ questionnaires were used to measure maternal primary outcome measures (n=15 scales/ questionnaires), childhood primary outcome measures (n=2), maternal secondary outcome measures (n=5), childhood secondary outcome measure (n=1) (Table 4).