EP21.10: Obstetrical outcomes following amniocentesis performed after 24 weeks of gestation: a systematic review and meta‐analysis

To evaluate the obstetrical outcomes of women undergoing late amniocentesis (defined as performed on or after 24 weeks of gestation). PubMed, Web of Science, Scopus, and Embase were searched from inception to 1 January2023. The obstetrical outcomes evaluated were preterm birth (PTB) < 37 weeks, PTB within 1 week from amniocentesis, premature prelabour rupture of membranes (PPROM), chorionamnionitis, placental abruption, and intrauterine fetal demise (IUFD). The rates of complications were pooled using a random-effect meta-analysis of proportions. Six studies of 2212 women undergoing late amniocentesis were included. The overall incidence of PTB < 37 weeks was 3.44%, while the incidence of PTB within one week from amniocentesis was 0.88%. The rate of PPROM was 2.71%. Chorionamnionitis occurred in 0.66% of cases, despite this data was reported only in one study and therefore pooled proportion analysis was not available. The incidence of placental abruption was 0.87%, while the rate of IUFD was 1.87%. Two out of three studies including also twin pregnancies provided data stratified according to the type of pregnancy. For twin pregnancies, the incidence of PTB within one week from amniocentesis was 7.84%. Finally, when considering the subgroup analysis according to the GA at which amniocentesis was performed (either before or after 32 weeks), the incidence of PTB within one week was 1.26% when amniocentesis was performed before 32 weeks and 6,58% when performed after 32 weeks. The risk of PTB within one week was significantly higher when amniocentesis was performed after 32 weeks (OR 7.38; 95% CI 1.53 – 35.57). The risks of complications after late amniocentesis are quite low, particularly when focusing on PTB within one week that was less than 1%. These data are useful for pre-procedure counselling but need to be confirmed by future large prospective studies sharing objective protocols and indications.