Abstract
To study the best possible luteinizing hormone (LH) threshold to predict ovulation within the 24, 48, and 72 h. Observational study. Multicenter collaborative study. A total of 107 women. Women collected daily first morning urine for hormonal assessment and underwent serial ovarian ultrasound. This is a secondary analysis of 283 cycles. The sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were estimated for varying ranges of LH thresholds. Receiver operating characteristic curves and cost-benefit ratios were used to estimate the best thresholds to predict ovulation. The best scenario to predict ovulation at random was within 24 h after the first single positive test. The false-positive rate was found to increase as (1) the cycle progressed or (2) two or three consecutive tests were used, or (3) ovulation was predicted within 48 or 72 h. Testing earlier in the cycle increases the predictive value of the test. The ideal thresholds to predict ovulation ranged between 25 and 30 mIU/ml with a PPV (50-60%), NPV (98%), LR+ (20-30), and LR- (0.5). At least, one day with LH ≥25 mIU/ml followed by three negatives (LH <25) occurred before ovulation in 31% of all cycles. When used throughout the cycle and evaluated together, peak-fertility type mucus with a positive LH test ≥25 mIU/ml provides a higher specificity than either mucus or LH testing alone (97-99 vs. 77-95 vs. 91%, respectively). We identified that beginning LH testing earlier in the cycle (day 7) with a threshold of 25-30 mIU/ml may present the best predictive value for ovulation within 24 h. However, prediction by LH testing alone may be affected negatively by several confounding factors so LH testing alone should not be used to define the end of the fertile window. Complementary markers should be further investigated to predict ovulation and identify the fertile window. The use of the peak cervical mucus along with an LH test may provide a higher specificity and predictive value than either of them alone. We recommend that manufacturers disclose their tests' threshold to the public.
Highlights
Affordable urinary ovulation predictor tests have become commonly used by those women wanting to become pregnant since they were first introduced in the 1980s [1]
It is important to note that using the luteinizing hormone (LH) test alone to delineate the end of the fertile window may provide a false end of the fertile window and may even occur before ovulation in one out of three cycles as shown in Figure 5 (31.1% of the cycles showed positivity followed by three daily negatives even though ovulation had not yet occurred)
We demonstrated that the combination of peak-fertility type cervical mucus (Score 4) increases the specificity and Positive predictive value (PPV) of the LH test
Summary
Affordable urinary ovulation predictor tests have become commonly used by those women wanting to become pregnant since they were first introduced in the 1980s [1] They could be used as an adjunct to Fertility Awareness Methods [2]. As pointed out by these studies, the LH peak is rather best described as a wave than as a peak with its surge occurring prior to ovulation; yet, LH levels may remain high after ovulation during the luteinization process. All of these factors may affect how these tests are interpreted by the user in relation to the day of ovulation
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call