Factors associated with spontaneous vaginal birth in nulliparous women at term: a systematic review

Abstract

Objective: The aim of this systematic review was to identify the factors associated with spontaneous vaginal birth at term, in nulliparous women with singleton pregnancy.Data sources: Nine databases were searched PubMed, MEDLINE Complete (EBSCO), Scopus, CINAHL Complete (EBSCO), Embase (Elsevier), Maternity and Infant Care (Ovid), Emcare (Ovid), Cochrane Central Register of Controlled Trials (CENTRAL which includes ClinicalTrials.gov) with dates extending from inception to 16 July 2021Methods of Study Selection: Quantitative studies of all designs, published in English, of nulliparous women with a singleton pregnancy and cephalic presentation, who experienced a spontaneous vaginal birth (SVB) at term were included. Covidence was used to manage citation screening and full text review. Two reviewers undertook quality appraisal and RCTs with high risk of bias (ROB 2.0) and other designs (QATSDD) scoring ≤ 50% were excluded.Tabulation, Integration, and Results: Data was abstracted from 78 studies (31 RCTs, 33 cohort, 9 cross-sectional, 4 prevalence and 2 case control) and factors associated with SVB were categorised as maternal, clinical care and fetal to synthesise findings. There was strong evidence to support interventions to address maternal BMI, birth intentions and fear of childbirth as well as childbirth education, breathing and exercise interventions in the antenatal period and midwifery models of care to increase SVB in nulliparas. Findings did not support routine induction as a means to promote SVB, but the relationship between maternal pelvic anatomy and fetal positioning and strategies to optimise labour progression emerged as promising areas for further research.Conclusion: How women give birth the first time is important, and this review highlights key domains where evidence synthesis can guide improvements in care and direct future research.