Identification of the LH surge by measuring intact and total immunoreactivity in urine for prediction of ovulation time

Quantification of urinary gonadotropins by specific assays may improve the evaluation of sex-specific hormonal changes in early infancy

OBJECTIVE

The aim of this study was to investigate the feasibility of different gonadotropin assays for determining total and intact luteinizing hormone (LH), and follicle-stimulating hormone (FSH) immunoreactivity in urine (U-LH-ir and U-FSH-ir, respectively) during early infancy.

DESIGN, PATIENTS AND MEASUREMENTS

Morning urine samples were obtained from 31 infants, aged between 0 and 6 months, to study the age-related course of urinary gonadotropins. Additionally, we investigated bi-hourly urine samples of a 5-day-old male neonate for 24 h to observe the course of urinary gonadotropins during a daily cycle. We employed different immunofluorometric assays for measuring total and intact U-LH-ir, and U-FSH-ir.

RESULTS

In neonates up to 21 days of age, the U-LH-ir levels measured by the regular LH assay (also detecting hCG) were significantly higher than those determined by the total (specific) LH assays (p = .004). U-FSH-ir was higher in girls than boys during both the first and the next 5 months (p = .02 and p < .001, respectively), whereas total U-LH-ir was higher in boys until 6 months of age (p < .001). Total U-LH-ir/U-FSH-ir ratio was significantly higher in boys than girls across the first half-year (p < .001).

CONCLUSIONS

The assessment of total U-LH-ir and U-FSH-ir, and their respective ratio constitutes a noninvasive, practical and scalable tool to investigate sex-specific changes during early infancy, with the ratio being significantly higher in boys than girls. Only highly specific LH assays detecting beta-subunit and its core fragment in addition to intact LH should be used for determining U-LH-ir in the neonatal period to avoid potential cross-reactivity with hCG of placental origin.

The negative impact of levothyroxine treatment on urinary luteinizing hormone measurements in pediatric patients with thyroid disease

Objectives

Previous studies suggest urinary luteinizing hormone (LH) and follicle-stimulating hormone (FSH) measurements by immunofluorometric assays (IFMA) as noninvasive alternatives to serum assays for puberty assessment. However, these studies excluded patients with other endocrine disorders and those taking medications. Besides, the recent discontinuation of IFMA manufacturing is a concern. We explored the utility of luminometric assays (LIA) for urinary gonadotropins and thyroid-stimulating hormone (TSH) determinations in euthyroid patients with thyroid pathologies.

Methods

We used LIA and IFMA assays to measure serum and first-morning-voided (FMV) urine LH, FSH, and TSH concentrations in euthyroid patients with various thyroid disorders. Of the 47 euthyroid patients with normal serum TSH (S-TSH) levels, 14 were receiving levothyroxine therapy.

Results

FMV total urinary LH (U-LH) concentrations correlated significantly with those measured in serum using either LIA (r=0.67, P<.001) or IFMA (r=0.83, P=.003) in patients not receiving levothyroxine treatment; however, no significant correlation could be detected in patients receiving levothyroxine regardless of the assay method (for LIA: r=0.50, P=.08 and IFMA r=0.44, P=.15). Urinary TSH (U-TSH) concentrations correlated poorly with those in serum in both the untreated and the treated groups (r=-0.13, P=.49, and r=-0.45, P=.11, respectively).

Conclusion

FMV total U-LH determinations by LIA can be used to assess pubertal development in patients with thyroid pathology, provided the euthyroid patient is not on levothyroxine treatment. U-TSH measurements by LIA cannot replace invasive S-TSH measurements at least in patients with normal S-TSH levels. Further research may reveal the utility of U-TSH determinations in patients with elevated S-TSH levels.

Urine Sampling Protocol Recommendations for Reliable Determination of Total Urinary Luteinizing Hormone Immunoreactivity in the Pediatric Population

This study investigates day-to-day variations in urinary luteinizing hormone (U-LH) concentrations in children, focusing on potential minimization or correction methods. 95 children and adolescents (51 boys, 44 girls, ages 5-17) provided daytime and evening urine samples for U-LH determinations over three consecutive days. No consistent day-to-day differences in U-LH levels were observed, although random variations, particularly in adolescents aged 13 or older, were noted. The net inter-assay CV% for U-LH changes over three days showed high variability, averaging 24.6% to 28.0% for boys and 21.6% to 27.3% for girls, independent of sex, collection time, or U-LH level. To reliably determine total urinary luteinizing hormone immunoreactivity in the pediatric population, it is advisable to collect multiple first-morning voided samples for at least three consecutive days as an interim solution, pending the development of a standardized protocol or correction method for varying urine composition. Strict adherence, especially for adolescents aged 13 or older, is vital.

Using Hormone Data and Age to Pinpoint Cycle Day within the Menstrual Cycle

Background and Objectives: Menstrual cycle tracking is essential for reproductive health and overall well-being. However, there is still an over-reliance on estimations that standard cycles are 28 days long, divided evenly between the follicular and luteal phases. Due to the variability of cycle length and cycle phase lengths, common methods of identifying where an individual is in their cycle are often inaccurate. This study used daily hormone monitoring obtained through a remote hormone-monitoring platform to evaluate hormone levels across a menstrual cycle to identify nuances in the follicular and luteal phases in individuals of different age groups. Materials and Methods: This study used a remote fertility testing system that quantitatively tracks luteinizing hormone (LH) and pregnanediol-3-glucuronide (PdG) through urine tests read by an AI-powered smartphone app. The study analyzed cycle data from 1233 users with a total of 4123 evaluated cycles. Daily levels for LH and PdG were monitored across multiple cycles. Results: This study determined that calculated cycle lengths tended to be shorter than user-reported cycle lengths. Significant differences were observed in cycle phase lengths between age groups, indicating that follicular phase length declines with age while luteal phase length increases. Finally, the study found that if an individual's age, first cycle day, and current hormone levels are known, population-level hormone data can be used to pinpoint which cycle phase and cycle day they are in with 95% confidence. Conclusions: At-home hormone monitoring technologies can allow patients and clinicians to track their cycles with greater precision than when relying on textbook estimations. The study's findings have implications for fertility planning, clinical management, and general health monitoring. Prior to this study, no standard existed for pinpointing where a person was in their cycle through only one measure of LH and PdG. These findings have the potential to fill significant gaps within reproductive healthcare and beyond.

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

OBJECTIVES

Most 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.

METHODS

We 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.

RESULTS

Total 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.

CONCLUSIONS

The 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.