Introduction: Several studies acknowledge that the presence of amniotic fluid sludge (AFS) is an independent predictive factor for preterm birth. In the present systematic review, we summarize research that focuses on the comparison of pregnancy outcomes among women with and without AFS.
Material and methods: Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar databases were systematically searched from inception. Both observational and randomized controlled studies were considered eligible provided that they reported data on pregnancy outcomes among women with and without AFS. Outcomes were not meta-analyzed because of the high heterogeneity in terms of selected population and outcome reporting.
Results: Seventeen studies of 2432 women were included in this review. Six studies evaluated women at high risk for preterm birth. Pregnancies complicated by AFS had a lower gestational age at delivery and increased incidence of preterm delivery at <37 weeks. Neonatal death rates and admission to the Neonatal Intensive Care Unit were also increased. Evidence in low-risk women, those with signs of preterm labor, in those carrying twins, and in women with cervical cerclage or Arabin pessary was extremely limited.
Conclusions: Women with AFS seem to deliver at an earlier gestational age, and preterm birth rates are also increased. Limited data seem to point to neonatal morbidity and mortality being increased. However, the presence of a direct association should not be assumed because the evidence is not adjusted for the presence of confounders.
Keywords: amniotic fluid; cervical insufficiency; preterm birth; sludge; systematic review.
© 2020 Nordic Federation of Societies of Obstetrics and Gynecology.