Amniotic fluid volume and pregnancy outcomes in twin pregnancies: A systematic review and meta-analysis

Abstract

Objective: To analyse amniotic fluid volume (AFV), specifically oligohydramnios or polyhydramnios, and associated pregnancy and neonatal outcomes in twin gestations through systematic review and meta-analysis. Methods: We utilised systematic review methodology to identify items within published and grey literature resources. Prospective and retrospective studies with a control group were included. Inclusion criteria were as follows: studies in English, twin pregnancy in which AFVs and associated pregnancy and/or neonatal outcomes were evaluated. Exclusion criteria included the presence of an anomalous fetus, chromosome abnormality, monochorionic diamniotic twin pregnancy complicated by twin–twin transfusion syndrome or twin-reversed arterial perfusion, twin gestations undergoing therapeutic interventions (i.e. fetoscopic laser photocoagulation and serial amniocentesis) and monochorionic monoamniotic twin pregnancy. Results: The literature search identified 1068 abstracts, only four met criteria for inclusion and analysis. The pooled data (two studies per outcome) revealed no significant difference in rate of pre-term delivery (OR: 2.94; CI: 0.20–43.81), pre-term delivery less than 32 weeks (OR: 1.97; CI: 0.43–9.12), umbilical cord pH < 7 (OR: 2.66; CI: 0.22–32.51), rate of stillbirth (OR: 4.13; CI: 0.40–42.70), neonatal death (OR: 1.48; CI: 0.05–43.94), rate of NICU admission (OR: 1.38; CI: 0.61–3.11) or rate of small-for-gestational-age (SGA) infants (OR: 1.39; CI: 0.33–5.94). Conclusion: Based on the pooled data (two studies per outcome), there was no difference in the fate of pre-term delivery, umbilical cord pH < 7, stillbirth, neonatal death or SGA infants. What is disturbing is the lack of studies (1946–2020) that analysed the association between AFV and pregnancy outcomes in twin pregnancies.