Beneficial effect of reduced oxygen concentration with transfer of blastocysts in IVF patients older than 40 years old

Abstract

The aim of the present study was to determine the impact of oxygen concentration on implan-tation, pregnancy and delivery rates in IVF patients older than 40 year old with transfer of blastocysts. Included were 558 women aged 23-45 years old undergoing IVF/ICSI procedures whose embryos were cultured at blastocyst stage under two different oxygen environments (a bi-gas system: 5.6% CO 2 in air and a tri-gas system: 5.6% CO 2 , 5% de O 2 and 89.4% N 2). The main outcome measures of this study are im-plantation, pregnancy and delivery rates. Im-plantation, pregnancy and delivery rates are found to be reduced in women older than 40 years old. The implantation and pregnancy rates are significantly higher in women older than 40 years old from the 5% of O 2 group, in comparison to the 20% group (25.00% versus 2.70% and 41.38% versus 5.56%; P < 0.05). The deliveries rates were 13.79% and 5.56% in the 5% and 20% oxygen groups respectively (P: NS). The birth-weight was similar in both study groups (P: NS). Gestational age was significantly longer in women from the 5% of O 2 group, in comparison to the 20% (36.87 versus 35.87 weeks, P < 0.05). Results indicated that the embryonic culture with 5% of oxygen and transfer of blastocysts in women older than 40 years old improve the results in the in Vitro fertilization/intracytoplasmic injection procedures (IVF/ICSI).