TTC | Infertility Support Forum - FETs in older women

I have a question regarding success rates for FETs in women over 40. In looking at the national SART data, I noticed that compared to same age fresh cycles, success rates for FETs tend to be lower for younger women (under 40), but oddly, higher for older women.

For example, for women under 35, the success rate for a fresh cycle with 2 embryos transferred is 47.5%, and for a FET (same # of embryos), 35.6%. However, for a women older than 42, the success rate for a fresh cycle with 3.1 embryos transferred is 6.2%, but for a FET with fewer embryos transferred (2.3), the success rate jumps to 13.9%! This is national data, so comparison is among large groups of women (no less than 961 in each group), so I’m guessing that the stats are reliable.

What accounts for this odd jump in success rates for FETs in older women? Is it simply that the women who end up with embryos to freeze are by definition more “fertile” (lower fsh, higher antral count, better egg quality)? Or could it be something external; perhaps the high doses meds given to women in their 40s have a negative impact on the endometrium? (I actually talked with a doctor who felt that this was the case—he only does low dose IVF). Do you think it’s possible that higher doses of FSH could impact endometrial health and implantation?

Thanks very much!
Sophie

Dear Sophie,

The higher than expected pregnancy rate for women over 40 is accounted for by the fact that some of these embryos were created when women were younger and also that these women stimulated well enough to have excess frozen embryos implies that they were a better than average prognosis group for their age. We see similar higher than expected rates in our Single embryo transfer program. Typically, patients over 40 who elect to transfer one embryo at a time have proven previous fertility i.e. children at home which is why they elect SET. Though the numbers are small 4 of 8 of our over 40 group have conceived through SET.

2 Comments

TheFertilityDoc - 03-18-2011, 09:44 AM

The higher than expected pregnancy rate for women over 40 is accounted for by the fact that some of these embryos were created when women were younger and also that these women stimulated well enough to have excess frozen embryos implies that they were a better than average prognosis group for their age. We see similar higher than expected rates in our Single embryo transfer program. Typically, patients over 40 who elect to transfer one embryo at a time have proven previous fertility i.e. children at home which is why they elect SET. Though the numbers are small 4 of 8 of our over 40 group have conceived through SET.

sophie - 03-18-2011, 09:58 AM

Thanks very much! I thought FET success rates were catagorized by the age of the women at the time of embryo freezing (not by age at FET), so this explanation makes sense.