Single selected blastocyst transfers maintained pregnancy outcome and reduced multiple pregnancies

Abstract

Transfer of more than one embryo following in vitro fertilization(IVF) / intracytoplasmic sperm injection(ICSI) cycles have increased pregnancy rates, however it has increased the incidence of triplets and twins. Increasing number of premature neonates caused by multiple pregnancies has become a serious problem in neonatal care units. It has been proposed that prolonging culture to the blastocyst stage would result in the automatic selection of good quality embryos for transfer, and minimize the incidence of triplets and twins. Retrospective analysis. Two thousand seven hundred and nineteen consecutive embryo transfers were carried out between January 1998 and March 2003 and they are included in this study. Embryos were obtained from patients < 40 years of age using the conventional IVF and ICSI procedures. A total of four hundred and twenty two blastocyst stage embryo transfers (BT) were carried out on day 5 after oocyte retrieval. Eighty nine of the 422 BT patients received single blastocyst transfer (SBT), of which 59 SBT patients received a single selected good quality blastocyst transfer(SSBT). Two hundred fifteen of the 422 BT patients received double BT. The analyzed data on pregnancy outcome and multiple pregnancy were compared as follows: a) single, double BT, b) SBT in patients belonging to different age groups (<30, 30–34, and 35–39), and c) good, fair or poor quality of BT. Statistical analysis was performed using the χ2 test. A P value of <0.05 was considered statistically significant. The clinical pregnancy rate and implantation rate have no significant difference between following SBT (49.4%; 49.4%) and double BT (59.1%; 44.0%). While significantly higher (p<0.01) multiple pregnancy rate was observed in double BT patients (3.3% v.s. 42.2%). The average birth weight of neonates was significantly smaller (p<0.01) following double BT than SBT (2,536g v.s. 3,004g). The clinical pregnancy rate following SBT was similar in patients belonging to <30 years (53.8%), 30–34 years (54.9%) and 35–39 years old (36.0%). Selected single good quality blastocyst transfers maintained pregnancy outcome and were able to avoid multiple pregnancies. It is recommended for patients with a risk for high-order multiple pregnancy.