A prospective evaluation of luteal phase length and natural fertility
Short luteal phase length may have a negative impact on natural fertility.
Volume 107, Issue 3, Pages 749–755
Natalie M. Crawford, M.D., David A. Pritchard, M.S., Amy H. Herring, Sc.D., Anne Z. Steiner, M.D., M.P.H.
To evaluate the impact of a short luteal phase on fecundity.
Prospective time-to-pregnancy cohort study.
Women trying to conceive, ages 30–44 years, without known infertility.
Daily diaries, ovulation prediction testing, standardized pregnancy testing.
Main Outcome Measure(s)
Subsequent cycle fecundity.
Included in the analysis were 1,635 cycles from 284 women. A short luteal phase (≤11 days including the day of ovulation) occurred in 18% of observed cycles. Mean luteal phase length was 14 days. Significantly more women with a short luteal phase were smokers. After adjustment for age, women with a short luteal phase had 0.82 times the odds of pregnancy in the subsequent cycle immediately following the short luteal phase compared with women without a short luteal phase. Women with a short luteal length in the first observed cycle had significantly lower fertility after the first 6 months of pregnancy attempt, but at 12 months there was no significant difference in cumulative probability of pregnancy.
Although an isolated cycle with a short luteal phase may negatively affect short-term fertility, incidence of infertility at 12 months was not significantly higher among these women.