Objective: To determine whether different ratios of administered LH-to-FSH influence the risk of clinically relevant late follicular P elevations and whether there is an optimal range of LH-to-FSH to mitigate this risk.
Design: Retrospective cohort.
Setting: Private academic center.
Patient(s): A total of 10,280 patients undergoing their first IVF cycle.
Main outcome measure(s): The ratio of exogenous LH-to-FSH throughout stimulation and association with absolute serum P level≥1.5 ng/mL on the day of hCG administration.
Result(s): Stimulations using no administered LH (N=718) had the highest risk of P elevation≥1.5 ng/mL (relative risk [RR]=2.0; 95% confidence interval [CI] 1.8-2.2). The lowest risk of P increase occurred with an LH-to-FSH ratio of 0.30:0.60 (20%; N=4,732). In contrast, ratios<0.30, reflecting proportionally less administered LH (N=4,847) were at increased risk for premature P elevation (32%, RR=1.6; 95% CI 1.5-1.7) as were ratios>0.60 (23%, RR 1.1; 95% CI 1.0-1.3). This pattern of lowest risk in the 0.30-0.60 range held true for cycles characterized by low, normal, and high response. When performing a logistic regression to control for multiple confounding variables this relationship persisted.
Conclusion(s): Absent or inadequate LH dosing is associated with a risk for a late follicular elevation in P sufficient to induce suboptimal outcomes. A total LH-to-FSH ratio of 0.30:0.60 was associated with the lowest risk of P elevation. Optimization of this parameter should be considered when making gonadotropin dosing decisions.
Keywords: Gonadotropins; exogenous FSH; exogenous LH; late follicular increase in progesterone; stimulation.
Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.