Prevention of twin pregnancy after in vitro fertilization/intracytoplasmic sperm injection based on strict embryo criteria: A prospective randomized trial

Abstract

The exponential increase in the incidence of multiple pregnancy is a direct consequence of the increased availability of assisted reproductive techniques (ART). The resulting higher costs for neonatal care, the increased neonatal morbidity and the financial and psychological effects on the couple indicate that a solution to this problem is urgently required. The objective of this randomized trial, in women <34 years of age who were undergoing IVF/ICSI, was to compare the pregnancy rates after transferring into the uterus one or two top quality embryos on day 3 after fertilization. A top quality embryo was characterized by the absence of multi-nucleated blastomeres, four or five blastomeres on day 2, seven or more cells on day 3, and <20% anucleated fragments. Randomization was carried out in 34 women with at least two top quality embryos available for transfer (17 had a single embryo transferred and 17 received two embryos). The clinical pregnancy rates were 59 and 71%, respectively (p = 0.72), and the implantation rates were 47% each. The twin pregnancy rates were 10 and 30%, respectively. The authors concluded that when top quality embryos are available, only one embryo should be transferred to reduce the likelihood of twin pregnancy.