An estrogen test to determine the times of potential fertility in women

Schiphorst, L. E. M.; Collins, William P.; Royston, J. P.

doi:10.1016/s0015-0282(16)48856-4

Cited by 25 publications

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“…Studies published by WHO have demonstrated that the median time for a defined rise in the concentration of urinary E3G occurred on day 9 of the menstrual cycle, approximately 118 h (approximately 5 days) before the urinary LH peak in women with regular menstrual cycles ( 32 , 33 ). Indeed, a rise in the concentration of E3G of 50% over the mean of the previous three values was shown to locate the start of the potentially fertile period (between day -3 and -7) in over 90% of the cycles ( 27 , 28 ), thus a combination of urinary E3G and LH determinations has been used for the prediction of the optimal timing for conception ( 29 – 31 , 34 ). On the other hand, current ovulation predictor kits (OPKs) do not detect any hormonal activity beyond LH surge for those who were “too late” and missed the day of LH surge, rather inform the ovulation time as a projection derived from the E3G and LH measurements from before the LH peak.…”

Section: Discussionmentioning

confidence: 99%

“…In ovulatory cycles, ovulation usually occurs about 14 days before the onset of the next period. The length of the normal ovulatory cycle may vary considerably (26)(27)(28)(29)(30)(31)(32)(33)(34)(35) days, mean 28 days), and extensive variations both in follicular (10-23 days) and luteal phases (7-19 days) have been reported (2,3). Thus, making the prediction of ovulation and appropriate timing for intercourse or natural cycle intrauterine insemination is rather challenging (2,4).…”

Section: Introductionmentioning

confidence: 99%

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Quantification of urinary total luteinizing hormone immunoreactivity may improve the prediction of ovulation time

et al. 2022

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ObjectivesMost of the currently available ovulation prediction kits provide a relatively rough estimation of ovulation time with a short fertility window. This is due to their focus on the maximum probability of conception occurring one day before ovulation, with no follow-up after LH surge until ovulation nor during the subsequent days thereafter. Earlier studies have shown that urine of reproductive age women contains at least 3 different molecular forms of luteinizing hormone (LH); 1) intact LH, 2) LH beta-subunit (LHβ) and a 3) small molecular weight fragment of LHβ, LHβ core fragment (LHβcf). The proportion of these LH forms in urine varies remarkably during the menstrual cycle, particularly in relation to the mid-cycle LH surge. In this exploratory study, we studied the potential implications of determining the periovulatory course of total LH immunoreactivity in urine (U-LH-ir) and intact LH immunoreactivity in serum (S-LH-ir) in the evaluation of the fertility window from a broader aspect with emphasis on the post-surge segment.MethodsWe determined total U-LH-ir in addition to intact S-LH-ir, follicle-stimulating hormone (FSH), progesterone, and estradiol in 32 consecutive samples collected daily from 10 women at reproductive age. Inference to the non-intact U-LH-ir levels was made by calculating the proportion of total U-LH-ir to intact S-LH-ir.ResultsTotal U-LH-ir increased along with LH surge and remained at statistically significantly higher levels than those in serum for 5 consecutive days after the surge in S-LH-ir. S-LH-ir returned to follicular phase levels immediately on the following day after the LH surge, whereas the same took 7 days for total U-LH-ir.ConclusionsThe current exploratory study provides preliminary evidence of the fact that U-LH-ir derived from degradation products of LH remains detectable at peak levels from the LH surge until ovulation and further during the early postovulatory period of fecundability. Thus, non-intact (or total) U-LH-ir appears to be a promising marker in the evaluation of the post-surge segment of the fertility window. Future studies are needed to unravel if this method can improve the prediction of ovulation time and higher rates of fecundability in both natural and assisted conception.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantification of urinary total luteinizing hormone immunoreactivity may improve the prediction of ovulation time

et al. 2022

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Identifying the fertile phase of the human menstrual cycle

Royston

1991

Statistics in Medicine

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The identification of the human fertile phase as the time during which a woman or a couple may conceive is elusive. The fertile time depends on many factors in each individual menstrual cycle and may be said to be more of a statistical than a physiological entity. This paper reviews the application of statistical methods to three areas related to conception and the fertile phase. The first is the prediction and detection of ovulation from serial measurements, such as hormones, basal body temperature and cervical mucus, throughout the menstrual cycle. Typically, such variables increase from some baseline level to a peak around ovulation (the most fertile time), then subside to low levels in the postovulatory phase. The statistical challenge is to detect the rise (signalling the onset of potential fertility) and subsequent fall. Analytic methods considered include thresholds, Bayesian change-point models and particularly the cumulative sum (cusum) technique which is both simple to apply and understand, and effective. The second area comprises appropriate methods of analysing and interpreting data from clinical studies of the fertile phase, especially in so-called natural family planning (NFP) where it is usual for women to observe several indices of potential fertility. Such studies usually try to establish the temporal relationships between markers of the fertile phase and examine the success of different combinations of markers in delineating the fertile time in comparison with a standard 'defined' phase, for example, the interval from three days before to two days after the peak of luteinizing hormone. The third area is the assessment of the probability of conception on certain days of the cycle, which is vital to the understanding of the fertile phase and its application to NFP. Direct estimation of such probabilities is impractical; instead, resort must be made to estimation by maximum likelihood of the parameters of specially constructed models. Suitable models are described. Finally, the need for a new prospective study of the probability of conception in relation to the markers of the fertile phase used in the symptothermal method of NFP is discussed.

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