Frequency of low serum LH is associated with increased early pregnancy loss in IVF/ICSI cycles

The role of LH during ovarian stimulation remains uncertain. Previous studies defined the low LH group using a single LH measurement on a predefined day of stimulation possibly not reflecting the entire follicular phase. This study retrospectively collected data from 619 IVF/ICSI cycles with GnRH antagonist and recombinant FSH. The low LH group was defined as LH concentration ≤0.8 mIU/ml at any time during the cycle. Pregnancy results were compared between patients with one episode of low LH or more than two episodes of low LH (study group) and those without low LH (control group). There was no difference in fertilization rates between the two groups (67.5 ± 1.7% versus 68.8 ± 1.0%, respectively). The implantation rates (20.4% versus 25.2%), clinical pregnancy rates (43.9% versus 45.2%) and live-birth rates (LBR) (23.7% versus 30.4%) appeared lower in the study group, but the differences were not significant. In the study group, there were significantly increased early pregnancy loss rates (31.1% versus 16.3%, P = 0.012). The odds of early pregnancy loss increases by 1.55 fold for increased episodes of low serum LH (P = 0.029). Whether the adverse outcome is due to impaired oocyte quality or an endometrial component deserves further investigation.