ABSTRACT
BACKGROUND: Ectopic pregnancy (EP) has been reported to occur in 1.4-5.4% of all clinical pregnancies resulting from in vitro fertilization (IVF) and embryo transfer (ET). Data on factors associated with abnormal embryo implantation following assisted conception are limited. MATERIALS AND METHODS: A systematic review and meta-analysis was performed to determine whether there is an association between the day (cleavage-stage, D3, versus blastocyst, D5) or the type (fresh versus frozen/thawed) of ET and EP rate. Risk factors for EP were evaluated in a retrospective study of 1194 women, who achieved pregnancy at our IVF unit between 2010 and 2016. RESULTS: Sixteen papers were considered for the meta-analysis. EP rate did not differ between D3 and D5 fresh ET groups (RR = 0.99, 95%CI: 0.76-1.30) and was higher after fresh versus frozen ET (RR = 1.56, 95%CI: 1.25-1.95). At our clinic, 21 (1.76%) pregnancies were documented as ectopic. The risk of EP was associated with tubal pathology (OR = 3.37, 95%CI: 1.39-8.2), previous appendectomy and past chlamydial infection. CONCLUSIONS: Present meta-analysis suggests that EP rate is similar following fresh blastocyst and cleavage ETs, but is significantly reduced after frozen compared with fresh ET. Our own findings demonstrate that tubal pathology has the major impact on EP occurrence following assisted conception.