Predictors of live birth and pregnancy success after in vitro fertilization in infertile women aged 40 and over

Abstract

Objective: The aim of this study was to evaluate pregnancy outcomes and the live birth rate at 1-year age increments in women aged ≥40 years undergoing fresh non-donor in vitro fertilization (IVF) and embryo transfer (ET), and to identify predictors of success in these patients.

Methods: This retrospective study was performed among women ≥40 years of age between 2004 and 2011. Of the 2,362 cycles that were conducted, ET was performed in 1,532 (73.1%).

Results: The clinical pregnancy rate and live birth rate in women ≥40 years significantly decreased with each year of increased age (p<0.001). Maternal age (odds ratio [OR], 0.644; 95% confidence interval [CI], 0.540-0.769; p<0.001), basal follicle-stimulating hormone (FSH) levels (OR, 0.950; 95% CI, 0.903-0.999; p=0.047), the number of high-quality embryos (OR, 1.258; 95% CI, 1.005 -1.575; p=0.045), and the number of transferred embryos (OR, 1.291; 95% CI, 1.064 -1.566; p=0.009) were significant predictors of live birth. A statistically significant increase in live birth rates was seen when ≥3 embryos were transferred in patients 40 to 41 years of age, whereas poor pregnancy outcomes were seen in patients ≥43 years of age, regardless of the number of transferred embryos. Moreover, the cumulative live birth rate increased in patients 40 to 42 years of age with repeated IVF cycles, but the follicle-stimulating hormone in those ≥43 years of age rarely showed an increase.

Conclusion: IVF-ET has acceptable outcomes in those <43 years of age when a patient's own oocytes are used. Maternal age, basal FSH levels, and the number of high-quality embryos and transferred embryos are useful predictors of live birth.

Keywords: Age; Female; Fertilization in vitro; Humans; Infertility; Live birth; Pregnancy.

Figure 1. Summary of in vitro fertilization-embryo transfer cycles in this study. COH, controlled ovarian hyperstimulation.

Figure 2. Pregnancy outcomes of in vitro fertilization-embryo transfer cycles in women 40 years of age and older. hCG, human chorionic gonadotropin. ^a)p<0.001 (linear-by-linear association).

Figure 3. Live birth rate according to the number of transferred embryos. ^a)p=0.017; ^b)p=0.002 (Fisher exact test).

Figure 4. Cumulative live birth rate (CLR) in patients who underwent repeated in vitro fertilization (IVF)-embryo transfer attempts. ^a)A CLR of 40% in 11 IVF cycles at age 40 yr; ^b)19% in 7 IVF cycles at age 41 yr; ^c)17% in 7 IVF cycles at age 42 yr; ^d)3% in 4 IVF cycles at ages 43 and 44 yr (p<0.001).