Is an Increase in LH Level During Artificial Frozen–Thawed Embryo Transfer (a-FET) Cycles Change Pregnancy Rate?

Introduation: Supplementation of estrogen in the early follicular phase in a-FET cycles for endometrium preparation can lead to a rise in LH level. Such a rise might interfere with endometrial receptivity. The association between a rise in LH level during a-FET cycle compared to early follicular phase level and pregnancy rates, has not been studied.

Aim:

To evaluate the association between high serum LH levels during a-FET cycles and positive pregnancy test.

Material and methods:

We compared a-FET cycles in which LH doubled/tripled itself from early follicular phase and further, during the same cycle, to cycles without rise in LH. Endometrium preparation was achieved by administration of 2mg*3\day estradiol valerate. Embryo transfer(ET) was conducted after achieving endometrial thickness>7mm. Vaginal progesterone supplementation was administered according to the embryo`s age. The b-hCG was measured 13-14days after ET

Results:

Data from 1685 FET cycles were retrieved between the years of 2007-2016. We calculated the LH ratio between LH on early follicular phase to the highest LH documented before the ET-day. The rate of doubling\tripling in LH was 44.6%\27.24%, of FET cycles, respectively. Mean patient age, parity, gravidity, number and age of embryos transferred per cycle were similar in cycles with and without rise in LH. Pregnancy rates per ET were similar between cycles with and without doubling\tripling LH level, (31.8%Vs.29.8%, P=0.38\31.2%Vs.30.3%, P=0.79,respectively).

Conclusion:

Pregnancy rate was higher among cycles with doubling and tripling LH values, but it was not significant statistically. LH rise during FET cycles does not alter pregnancy rate. Therefore monitoring of LH levels should not be conducted.