Does cleavage‐ versus blastocyst‐stage embryo transfer improve fertility rates in women over 38 years of age undergoing assisted reproductive technology?

Abstract

AbstractObjectiveTo evaluate whether extending embryo culture to day 5 (D5) affects pregnancy rates in women older than 38 years undergoing in vitro fertilization (IVF).MethodsThis retrospective, observational cohort study included data from fresh IVF cycles of women over 38 years, during 2011–2021. The cohort was divided according to day 3 (D3) versus D5 embryo transfer (ET).ResultsA total of 346 patients (ages 38–45 years) who underwent 496 IVF cycles were included, each yielding one to six embryos. A total of 374 (75%) fresh D3 ETs were compared with 122 (25%) D5 ETs. Demographically, there were more nulliparas in the D3 group (189 [50.9%] vs 47 [38.8%], P = 0.021). Higher gonadotropin dosage was used (3512 ± 1346 vs 3233 ± 1212 IU, P = 0.045) and lower maximum estradiol levels were reached in the D3 group (1129 ± 685 vs 1432 ± 708 pg/mL, P = 0.002). Thirty‐three (27%) of the D5 cycles resulted in transfer cancelation due to failure of blastocyst formation (P = 0.001). However, clinical pregnancy rates (P = 0.958), live birth rates (P = 0.988), and miscarriage rates (P = 0.710) did not differ between D3 and D5 ETs. Multivariable logistic regression for clinical pregnancy rate showed that day of transfer did not have a significant effect on the odds (P = 0.376), but maternal age (P = 0.001) and number of retrieved oocytes (P = 0.009) were significant variables.ConclusionsIn older women, culturing embryos to blastocyst stage can decrease invalid ETs without reducing pregnancy rates. Cancelation rates are higher but it may avoid interventions and conserve valuable time.