High frequency of luteal phase deficiency and anovulation in recreational women runners: Blunted elevation in follicle-stimulating hormone observed during luteal-follicular transition

The purposes of this investigation were to evaluate the characteristics of three consecutive menstrual cycles and to determine the frequency of luteal phase deficiency (LPD) and anovulation in a sample of sedentary and moderately exercising, regularly menstruating women. For three consecutive menstrual cycles, subjects collected daily urine samples for analysis of FSH, estrone conjugates (E1C), pregnanediol-3-glucuronide (PdG), and creatinine (Cr). Sedentary (n = 11) and exercising (n = 24) groups mere similar in age (27.0 +/- 1.3 yr), weight (60.3 +/- 3.1 kg), gynecological age (13.8 +/- 1.2 yr), and menstrual cycle length (28.3 +/- 0.8 days). Menstrual cycles were classified by endocrine data as ovulatory, LPD, or anovulatory. No sedentary women (0%) had inconsistent menstrual cycle classifications fr-om cycle to cycle, but 46% of the exercising women were inconsistent. The sample prevalence of LPD in the exercising women was 48%, and the 3-month sample incidence was 79%. In the sedentary women, 90% of all menstrual cycles were ovulatory (SedOvul; n = 28), whereas in the exercising women only 45% were ovulatory (ExOvul; n = 30); 43% were LPD (ExLPD; n = 28), and 12% were anovulatory (ExAnov; n = 8). In ExLPD cycles, the follicular phase was significantly longer (17.9 +/- 0.7 days), and the luteal phase was significantly shorter(8.2 +/- 0.5 days) compared to ExOvul (14.8 +/- 0.9 and 12.9 +/- 0.3 days) and SedOvul(15.9 +/- 0.6 and 12.9 +/- 0.4 days) cycles. Luteal phase PdG excretion was lower (P < 0.001) in ExLPD (2.9 +/- 0.3 mu g/mg Cr) and ExAnov (0.8 +/- 0.1 mu g/mg Cr) cycles compared to SedOvul cycles (5.0 +/- 0.4 mu g/mg Cr). ExOvul cycles also had less (P < 0.01) PdG excretion during the luteal phase (3.7 +/- 0.3 mu g/mg Cr) than the SedOvul cycles. E1C excretion during follicular phase days 2-5 was lower (P = 0.05) in ExOvul, ExLPD, and ExAnov cycles compared to SedOvul cycles and remained lower (P < 0.02) in the ExLPD and ExAnov cycles during days 6-12. The elevation in FSH during the luteal-follicular transition was lower (P < 0.007) in ExLPD (0.7 +/- 0.1 ng/mg Cr) cycles compared to SedOvul and ExOvul cycles (1.0 +/- 0.1 and 1.1 +/- 0.1 ng/mg Gr, respectively). Energy balance and energy availability were lower (P < 0.05) in ExAnov cycles than in other menstrual cycle categories. The blunted elevation in FSH during the luteal-follicular transition in exercising women with LPD may explain their lower follicular estradiol levels. These alterations in FSH may act in concert with disrupted LH pulsatility as a primary and proximate factor in the high frequency of luteal phase and ovulatory disturbances in regularly menstruating, exercising women.