Elevated basal FSH and embryo quality: lessons from extended culture embryos

The relationship between elevated basal FSH and embryo quality remains a topic of heated discussion among practitioners of ART. Some authors suggest a negative effect of raised FSH on the quality of embryos and therefore on IVF treatment outcome. We postulate that women with elevated FSH who respond well to ovarian stimulation and have embryos to transfer, have the same chance of conceiving like women of a similar age with normal FSH. To test this hypothesis, we studied women with elevated basal FSH who made enough embryos to qualify for blastocyst culture and day 5 embryo transfer.

Analysis of data collected prospectively, on women age 25–43 years, who underwent IVF between January 2005 and December 2006. The women were divided into: those with high FSH (≥10 IU/L) and women with normal FSH (<10 IU/L). We analysed data to show treatment outcome in the two groups, following embryo transfer on day 3 and after transfer on day 5. Outcome measures include number of oocytes retrieved, number of embryos available, implantation rate, pregnancy and live birth rate.

Among the 1,858 women who under-went a day 3 transfer, 1,368 had basal FSH ≤ 10 IU/L, and in 492 basal FSH was above 10 IU/L. The average number of oocytes retrieved was lower among women with elevated FSH (10.12 ± 5.6 Vs 6.16 ± 3.9). Women with a normal FSH, had a higher pregnant and live birth rate than those with elevated FSH (43.3% vs 27.9% p = 0.021) and (30.8% vs 17.6% p = 0.028) respectively. 398 women made enough embryos to qualify for extended embryo culture to blastocysts. Of these 366 had an FSH ≤ 10 IU/L and 32 had FSH > 10 IU/L. In this group, there was no significant difference in the pregnancy and live birth rates between women with elevated and those with normal FSH, (67.2% vs 65.6%) and (51.9% vs 43.8%) respectively. In this selected group of women where quantity is not an issue, the quality of embryos was same irrespective of whether the basal FSH was low or high.

Women with elevated basal FSH who respond well to stimulation and generate a good number of oocytes / embryos have a chance of becoming pregnant and having a live birth similar to that of women of their age. Women should therefore not be denied the benefits of IVF based solely on the basal FSH level as a subset may respond well and therefore have a good chance of taking home a baby.