Factors affecting pregnancy in IVF: age and duration of embryo transfer

Abstract 

The aim of this retrospective study was to investigate factors affecting clinical pregnancy rates, especially age and duration of embryo transfer, in IVF/intracytoplasmic sperm injection cycles (1313 embryo transfers). Overall clinical pregnancy rate was 30.0% (n=394). Clinical pregnancy rates were found to be 31.6% for the <44s interval, 25.9% for the 45–59 s interval and 23.6% for the ⩾60s interval (P=0.020). In the <35year age group, clinical pregnancy rates were 35.1%, 29.9% and 30.6%, and in the ⩾35year age group, they were 26.9%, 21.0% and 13.4% (P=0.013), respectively. According to logistic regression analyses, the odds of failed pregnancy increased by 1.61 times [95% confidence interval (CI) 1.07–2.41] for embryo transfer durations longer than 60s and odds ratios of a failed pregnancy were 1.53 (95% CI 1.18–1.99) in the ⩾35year age group, 1.49 (95% CI 1.05–2.12) for fewer than five oocytes and 3.38 (95% CI 2.10–5.43) for fewer than two transferred embryos. In conclusion, to increase the likelihood of a successful pregnancy in women over 35years of age, the duration of embryo transfer must be kept below 60s. The number of oocytes obtained and the number of transferred embryos also play a role in the success of pregnancy.

Keywords: age, catheter, embryo transfer duration, prognostic factors