Sporadic appearance of luteal-phase defect in prospective assessment

We studied the sporadic appearance of luteal-phase defect in the prospective assessment of consecutive cycles. Basal body temperature (BBT) was recorded in 36 women (20-35 years of age) for at least 3 consecutive cycles (total of 194 cycles). These BBT records were analyzed for pattern and luteal-phase length (LPL). Furthermore, the relationship was investigated between the BBT and luteal function in terms of serum hormonal levels and endometrial dating in the luteal phase. The length of the transitional period from the hypothermic to the hyperthermic phase was also studied in relation to luteal function in 59 women (21-33 years of age). The results were as follows: (1) Different BBT patterns and LPLs in consecutive cycles occurred in 36 and 67% of the observed cycles, respectively. (2) Cycles with abnormal steroid levels and endometrial dating were observed sporadically. (3) The length of the transitional period appeared useful for prospective evaluation of luteal function. These findings suggest that the conditions of the luteal function do not appear in every cycle of each woman. Therefore, assessing the function of one cycle seems of little use in predicting the function of the next or future cycles.