Is Blastocyst ET Better Than Day 3-ET With Assisted Hatching in the Older Patient?

Abstract

Objective: Blastocyst transfer (BT) is gaining general acceptance as an effective modality to achieve pregnancy while decreasing the risk of high order gestations. We have recently reported increased pregnancy rates with BT compared to Day 3 embryo transfer (D3-ET) in good prognosis patients under age 40. It remains to be seen if BT is indicated in older women and whether it offsets the potential advantage of assisted hatching (AH) with D3-ET. In this study we compare cycle outcomes in similar populations of women over 40 years who had BT versus D3-ET with AH. Design: Retrospective study. Materials and Methods: Since 1998, patients with >3 eight-cell embryos on day 3 were offered BT. To date, 45 such cycles were in women over 40, of which 26 chose BT. The remaining 18 cycles who had D3-ET with AH along with 8 similar cycles in 1997 formed the comparison group. During this period, 146 blastocyst transfers occurred in women under age 40 who met these same criteria. All patients used their own eggs for IVF (±ICSI). P1 + 10% SSS (Irvine Scientific) was used until day 3; embryos were transferred to Blastocyst medium (Irvine Scientific) + 10% SSS for the BT group. ET was performed by the same physician using a Tefcat catheter. Implantation was defined as an ultrasound documented gestational sac and a viable pregnancy as fetal cardiac activity. Results: The age range was 40–44. The mean age in the BT group was 40.9 compared to 41.6 in the day 3 group. There were no differences in average number of eggs harvested (14.4 for BT v. 12.3 for D3-ET) or in eight cell embryos on day 3 (6.2 v. 5.4.) Only one patient in the BT group arrested at the 8-cell stage and had no embryo transfer. Significantly less embryos were transferred per cycle with BT (2.5) than with day-3 ET (6.5); p<0.001. The implantation rate with BT was 12% (8/66) compared to 5% for day-3 ET (8/170); p=0.07. Viable pregnancy rates for BT were similar (23%, 6/26) compared to day-3 ET (19%, 5/26); p>0.1. This compares to a rate of 60% (87 of 146 cycles) in women under 40 undergoing BT at our center. Conclusions: In older patients with good embryos, the yield of blastocyst formation is reassuring (26/27 cycles) but their pregnancy rate remains significantly lower than their younger counterparts. D3-ET with AH does not appear to improve outcome compared to BT. This justifies extending embryo culture to day 5. While BT may help limit the number of embryos transferred, the very rare occurrence of high order multiple gestation in older patients makes eliminating this risk a low priority. However, older women may benefit from information extended culture gives them regarding their egg quality which may guide them in decisions for future therapy.