Energy Availability Is Associated With Luteinizing Hormone Pulse Frequency and Induction of Luteal Phase Defects

Department

Health Promotion

Document Type

Article

Publication Source

The Journal of Clinical Endocrinology & Metabolism

Publication Date

2019-09-20

Volume

105

Issue

1

First Page

185

Last Page

193

Abstract

Objective: Determine the interrelations between reductions in energy availability (EA), luteinizing hormone (LH) pulse frequency, and the induction of menstrual disturbances in previously sedentary, ovulatory women.

Methods: Secondary analysis of a randomized controlled trial consisting of a 3-month controlled diet and supervised exercise program. EA was calculated daily by measured energy intake (kcal) and exercise energy expenditure (kcal) normalized to fat-free mass (kg) and averaged during baseline and each of 3 intervention menstrual cycles. Blood samples were obtained every 10 minutes for 24 hours in the early follicular phase before the intervention and after 3 months of diet and exercise (n = 14). LH pulse dynamics were assessed by Cluster. Linear mixed models determined whether EA predicts LH pulse frequency and LH pulse frequency predicts luteal phase defects (LPDs).

Results: Subjects were 20 ± 1 years old, 165.1 ± 1.4 cm tall, and weighed 58.9 ± 1.5 kg. LH pulse frequency decreased from 0.82 ± 0.06 pulses/h to 0.63 ± 0.09 pulses/h (P = 0.048) as a result of the intervention which produced modest (-3.2 ± 0.6 kg) weight loss. EA, averaged across a menstrual cycle, predicted LH pulse frequency (P = 0.003) such that a single-unit decrease in EA was associated with a 0.017 pulses/h decrease in LH pulse frequency. LH pulse frequency in cycles with LPDs was 49% of that observed in cycles with no menstrual disturbances and for every 0.1-unit decrease in LH pulse frequency, the odds of having an LPD were 22× greater than having an optimal ovulatory cycle (P = 0.01).

Conclusions: Modest reductions in EA over a prolonged period are associated with decreased LH pulse frequency and the induction of menstrual disturbances.

DOI

10.1210/clinem/dgz030

https://doi.org/10.1210/clinem/dgz030

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