IVF/ICSI treatment and the risk of iatrogenic preterm birth in singleton pregnancies: systematic review and meta-analysis of cohort studies

Preterm birth (PTB) is more frequent among in vitro fertilization (IVF) as compared to natural conception and recent research in this group describes an increase of its spontaneous etiology. However, clear description and quantification of iatrogenic preterm birth (IPTB) was not determined in IVF/ICSI (intra-cytoplasmic sperm injection) conceptions. This study quantifies the risk of IPTB in singleton pregnancies resulting from IVF/ICSI as compared to spontaneous conceptions (SCs). Web-based databases search (PubMed/Medline, Scopus, Web of Science) from inception up to January 2019 looking for cohort studies comparing the risk of IPTB in singleton pregnancies obtained with IVF/ICSI (intervention group) or SC (control group). Only studies with clear distinction of spontaneous and indicated PTB were included. Primary outcome was IPTB before 37 weeks of gestation, defined as indicated delivery for any medical recommendation. All pertinent secondary outcomes were also included: IPTB Pooled crude analysis showed a sample size of 9590 births with significant increase in IPTB I2 = 67%). Pooled analysis was impossible for most secondary outcomes due to lack of available data and failed to show statistical significance for abnormal CTG. The risk for IPTB due to abruptio placentae or placenta previa was significantly increased in IVF/ICSI pregnancies (two studies, 561 pregnancies; pooled proportion IPTB IVF/ICSI 2.12% vs. SC 1.06%; OR = 5.41; 95% CI: 1.26–23.25; I2: 0%). The risk of IPTB The risk of IPTB below 37 weeks in singleton pregnancies achieved after IVF/ICSI is more than double than that occurring in natural conception.