Lindsey A. Sjaarda

Biological variability in serum anti-Müllerian hormone throughout the menstrual cycle in ovulatory and sporadic anovulatory cycles in eumenorrheic women

STUDY QUESTION Does serum anti-Müllerian hormone (AMH) vary significantly throughout both ovulatory and sporadic anovulatory menstrual cycles in healthy premenopausal women? SUMMARY ANSWER Serum AMH levels vary statistically significantly across the menstrual cycle in both ovulatory and sporadic anovulatory cycles of healthy eumenorrheic women. WHAT IS KNOWN ALREADY Studies to date evaluating serum AMH levels throughout the menstrual cycle have conflicting results regarding intra-woman cyclicity. No previous studies have evaluated an association between AMH and sporadic anovulation. STUDY DESIGN, SIZE, DURATION We conducted a prospective cohort study of 259 regularly menstruating women recruited between 2005 and 2007. PARTICIPANTS/MATERIALS, SETTING, METHODS Women aged 18-44 years were followed for one (n = 9) or two (n = 250) menstrual cycles. Anovulatory cycles were defined as any cycle with peak progesterone concentration ≤5 ng/ml and no serum LH peak on the mid or late luteal visits. Serum AMH was measured at up to eight-time points throughout each cycle. MAIN RESULTS AND THE ROLE OF CHANCE Geometric mean AMH levels were observed to vary across the menstrual cycle (P < 0.01) with the highest levels observed during the mid-follicular phase at 2.06 ng/ml, decreasing around the time of ovulation to 1.79 ng/ml and increasing thereafter to 1.93 (mid-follicular versus ovulation, P < 0.01; ovulation versus late luteal, P = 0.01; mid-follicular versus late luteal, P = 0.05). Patterns were similar across all age groups and during ovulatory and anovulatory cycles, with higher levels of AMH observed among women with one or more anovulatory cycles (P = 0.03). LIMITATIONS, REASONS FOR CAUTION Ovulatory status was not verified by direct visualization. AMH was analyzed using the original Generation II enzymatically amplified two-site immunoassay, which has been shown to be susceptible to assay interference. Thus, absolute levels should be interpreted with caution, however, patterns and associations remain consistent and any potential bias would be non-differential. WIDER IMPLICATIONS OF THE FINDINGS This study demonstrates a significant variation in serum AMH levels across the menstrual cycle regardless of ovulatory status. This variability, although statistically significant, is not large enough to warrant a change in current clinical practice to time AMH measurements to cycle day/phase. STUDY FUNDING/COMPETING INTERESTS This research was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health, Bethesda, MD (Contracts # HHSN275200403394C, HHSN275201100002I Task 1 HHSN27500001). The authors have no conflicts of interest to declare.

Metabolomic Profiling of Amino Acids and β-Cell Function Relative to Insulin Sensitivity in Youth

CONTEXT In longitudinal studies of adults, elevated amino acid (AA) concentrations predicted future type 2 diabetes mellitus (T2DM). OBJECTIVE The aim of the present investigation was to examine whether increased plasma AA concentrations are associated with impaired β-cell function relative to insulin sensitivity [i.e. disposition index (DI)], a predictor of T2DM development. DESIGN, SETTING, AND PARTICIPANTS Metabolomic analysis for fasting plasma AAs was performed by tandem mass spectrometry in 139 normal-weight and obese adolescents with and without dysglycemia. First-phase insulin secretion was evaluated by a hyperglycemic (∼225 mg/dl) clamp and insulin sensitivity by a hyperinsulinemic-euglycemic clamp. DI was calculated as the product of first-phase insulin and insulin sensitivity. RESULTS DI was positively associated with branched-chain AAs (leucine/isoleucine and valine; r = 0.27 and 0.29, P = 0.001), neutrally transported AAs (phenylalanine and methionine; r = 0.30 and 0.35, P < 0.001), basic AAs (histidine and arginine; r = 0.28 and 0.23, P ≤ 0.007), serine (r = 0.35, P < 0.001), glycine (r = 0.26, P = 0.002), and branched-chain AAs-derived intermediates C3, C4, and C5 acylcarnitine (range r = 0.18-0.19, P ≤ 0.04). CONCLUSION In youth, increased plasma AA concentrations are not associated with a heightened metabolic risk profile for T2DM; rather, they are positively associated with β-cell function relative to insulin sensitivity. These contrasting observations between adults and youth may be a reflection of developmental differences along the lifespan dependent on the combined impact of the aging process together with the impact of progressive obesity.

Failure to Consider the Menstrual Cycle Phase May Cause Misinterpretation of Clinical and Research Findings of Cardiometabolic Biomarkers in Premenopausal Women

Biomarker assessment plays a critical role in the study and prevention of disease. However, variation in biomarkers attributable to the menstrual cycle in premenopausal women may impair understanding the role of certain biomarkers in disease development and progression. Thus, in light of the recently increasing evidence of menstrual cycle variability in multiple cardiometabolic biomarkers, a reexamination of approaches for appropriately studying and diagnosing cardiovascular disease in premenopausal women is warranted. We reviewed studies (from 1934 through 2012) evaluating changes in cardiometabolic biomarkers across phases of the menstrual cycle, including markers of oxidative stress, lipids, insulin sensitivity, and systemic inflammation. Each was observed to vary significantly during the menstrual cycle. For example, nearly twice as many women had elevated cholesterol levels warranting therapy (≥200 mg/dL) during the follicular phase compared with the luteal phase (14.3% vs. 7.9%), with only 3% having consistently high levels during all phases of the cycle. Similarly, nearly twice as many women were classified as being at an elevated risk of cardiovascular disease (high sensitivity C-reactive protein >3 mg/L) during menses compared with other phases (12.3% vs. 7.4%). Menstrual cycle-associated variability in cardiometabolic biomarkers is an important source of variability that should be accounted for in both research and clinical settings.

Subclinical Hypothyroidism and Thyroid Autoimmunity Are Not Associated With Fecundity, Pregnancy Loss, or Live Birth

CONTEXT Prior studies examining associations between subclinical hypothyroidism and antithyroid antibodies with early pregnancy loss and live birth suggest mixed results and time to pregnancy (TTP) has not been studied in this patient population. OBJECTIVE This study sought to examine associations of prepregnancy TSH concentrations and thyroid autoimmunity with TTP, pregnancy loss, and live birth among women with proven fecundity and a history of pregnancy loss. DESIGN AND SETTING This was a prospective cohort study from a large, randomized controlled trial that took place at four medical centers in the United States. PATIENTS OR OTHER PARTICIPANTS Healthy women, ages 18-40 y, who were actively attempting to conceive and had one or two prior pregnancy losses and no history of infertility were eligible for the study. INTERVENTION There were no interventions. MAIN OUTCOME MEASURE TTP, pregnancy loss, and live birth. RESULTS Women with TSH ≥ 2.5 mIU/L did not have an increased risk of pregnancy loss (risk ratio, 1.07; 95% confidence interval [CI], 0.81-1.41) or a decrease in live birth rate (risk ratio, 0.97; 95% CI, 0.88-1.07) or TTP (fecundability odds ratio, 1.09; 95% CI, 0.90-1.31) compared with women with TSH <2.5 mIU/L after adjustment for age and body mass index. Similar findings were observed for women with thyroid autoimmunity and after additional adjustment for treatment assignment. CONCLUSIONS Among healthy fecund women with a history pregnancy loss, TSH levels ≥ 2.5 mIU/L or the presence of antithyroid antibodies were not associated with fecundity, pregnancy loss, or live birth. Thus, women with subclinical hypothyroidism or thyroid autoimmunity can be reassured that their chances of conceiving and achieving a live birth are likely unaffected by marginal thyroid dysfunction.

Is anti-müllerian hormone associated with fecundability? Findings from the EAGeR trial

OBJECTIVE The objective of the study was to evaluate whether anti-Müllerian hormone (AMH) is associated with fecundability among women with proven fecundity and a history of pregnancy loss. DESIGN This was a prospective cohort study within a multicenter, block-randomized, double-blind, placebo-controlled clinical trial ( clinicaltrials.gov , number NCT00467363). SETTING The study was conducted at four US medical centers (2006-2012). PARTICIPANTS Participating women were aged 18-40 years, with a history of one to two pregnancy losses who were actively attempting pregnancy. MAIN OUTCOME MEASURES Time to human chorionic gonadotropin detected and clinical pregnancy were assessed using Cox proportional hazard regression models to estimate fecundability odds ratios (fecundability odds ratios with 95% confidence interval [CI]) adjusted for age, race, body mass index, income, low-dose aspirin treatment, parity, number of previous losses, and time since most recent loss. Analyses examined by preconception AMH levels: low (<1.00 ng/mL, n = 124); normal (referent 1.00-3.5 ng/mL, n = 595); and high (>3.5 ng/mL, n = 483). RESULTS Of the 1202 women with baseline AMH levels, 82 women with low AMH (66.1%) achieved an human chorionic gonadotropin detected pregnancy, compared with 383 with normal AMH (65.2%) and 315 with high AMH level (65.2%). Low or high AMH levels relative to normal AMH (referent) were not associated with fecundability (low AMH: fecundability odds ratios 1.13, 95% CI 0.85-1.49; high AMH: FOR 1.04, 95% CI 0.87-1.24). CONCLUSIONS Lower and higher AMH values were not associated with fecundability in unassisted conceptions in a cohort of fecund women with a history of one or two prior losses. Our data do not support routine AMH testing for preconception counseling in young, fecund women.

Previous prelabor or intrapartum cesarean delivery and risk of placenta previa

OBJECTIVE The purpose of this study was to examine the association between previous cesarean delivery and subsequent placenta previa while distinguishing cesarean delivery before the onset of labor from intrapartum cesarean delivery. STUDY DESIGN We conducted a retrospective cohort study of electronic medical records from 20 Utah hospitals (2002-2010) with restriction to the first 2 singleton deliveries of nulliparous women at study entry (n=26,987). First pregnancy delivery mode was classified as (1) vaginal (reference), (2) cesarean delivery before labor onset (prelabor), or (3) cesarean delivery after labor onset (intrapartum). Risk of second delivery previa was estimated by previous delivery mode with the use of logistic regression and was adjusted for maternal age, insurance, smoking, comorbidities, previous pregnancy loss, and history of previa. RESULTS Most first deliveries were vaginal (82%; n=22,142), followed by intrapartum cesarean delivery (14.6%; n=3931), or prelabor cesarean delivery (3.4%; n=914). Incidence of second delivery previa was 0.29% (n=78) and differed by previous delivery mode: vaginal, 0.24%; prelabor cesarean delivery, 0.98%; intrapartum cesarean delivery, 0.38% (P<.001). Relative to vaginal delivery, previous prelabor cesarean delivery was associated with an increased risk of second delivery previa (adjusted odds ratio, 2.62; 95% confidence interval, 1.24-5.56). There was no significant association between previous intrapartum cesarean delivery and previa (adjusted odds ratio, 1.22; 95% confidence interval, 0.68-2.19). CONCLUSION Previous prelabor cesarean delivery was associated with a >2-fold significantly increased risk of previa in the second delivery, although the approximately 20% increased risk of previa that was associated with previous intrapartum cesarean delivery was not significant. Although rare, the increased risk of placenta previa after previous prelabor cesarean delivery may be important when considering nonmedically indicated prelabor cesarean delivery.

Luteal Phase Deficiency in Regularly Menstruating Women: Prevalence and Overlap in Identification Based on Clinical and Biochemical Diagnostic Criteria

CONTEXT Although adequate luteal hormone production is essential for establishing pregnancy, luteal phase deficiency (LPD) is poorly characterized among eumenorrheic women. OBJECTIVE We assessed the prevalence and overlap of two established LPD diagnostic criteria: short luteal phase duration less than10 days (clinical LPD) and suboptimal luteal progesterone of 5 ng/mL or less (biochemical LPD) and their relationship with reproductive hormone concentrations. DESIGN, SETTING, AND PARTICIPANTS We conducted a prospective study in western New York (2005-2007) following 259 women, aged 18-44 years, for up to two menstrual cycles. RESULTS Among ovulatory cycles with recorded cycle lengths (n = 463), there were 41 cycles (8.9%) with clinical LPD, 39 cycles (8.4%) with biochemical LPD, and 20 cycles (4.3%) meeting both criteria. Recurrent clinical and biochemical LPD was observed in eight (3.4%) and five (2.1%) women, respectively. Clinical and biochemical LPD were each associated with lower follicular estradiol (both P ≤ .001) and luteal estradiol (P = .03 and P = .02, respectively) after adjusting for age, race, and percentage body fat. Clinical, but not biochemical, LPD was associated with lower LH and FSH across all phases of the cycle (P ≤ .001). CONCLUSIONS Clinical and biochemical LPD were evident among regularly menstruating women. Estradiol was lower in LPD cycles under either criterion, but LH and FSH were lower only in association with shortened luteal phase (ie, clinical LPD), indicating that clinical and biochemical LPD may reflect different underlying mechanisms. Identifying ovulation in combination with a well-timed luteal progesterone measurement may serve as a cost-effective and specific tool for LPD assessment by clinicians and researchers.

Sexual activity, endogenous reproductive hormones and ovulation in premenopausal women.

We investigated whether sexual activity was associated with reproductive function in the BioCycle Study, a prospective cohort study that followed 259 regularly menstruating women aged 18 to 44years for one (n=9) or two (n=250) menstrual cycles in 2005-2007. Women were not attempting pregnancy nor using hormonal contraceptives. History of ever having been sexually active was assessed at baseline and frequency of sexual activity, defined as vaginal-penile intercourse, was self-reported daily throughout the study. Serum concentrations of estradiol, luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone, and testosterone were measured up to 8times/cycle. Sporadic anovulation was identified using peak progesterone concentration. Linear mixed models were used to estimate associations between sexual activity and reproductive hormone concentrations and generalized linear models were used to estimate associations with sporadic anovulation. Models were adjusted for age, race, body mass index, perceived stress, and alcohol consumption and accounted for repeated measures within women. Elevated concentrations of estrogen (+14.6%, P<.01), luteal progesterone (+41.0%, P<.01) and mid-cycle LH (+23.4%, P<.01), but not FSH (P=.33) or testosterone (P=.37), were observed in sexually active women compared with sexually inactive women (no prior and no study-period sexual activity); sexually active women had lower odds of sporadic anovulation (adjusted odds ratio=0.34, 95% confidence interval: 0.16-0.73). Among sexually active women, frequency of sexual activity was not associated with hormones or sporadic anovulation (all P>.23). Findings from our study suggest that ever having been sexually active is associated with improved reproductive function, even after controlling for factors such as age.

Customized large-for-gestational-age birthweight at term and the association with adverse perinatal outcomes

OBJECTIVE Using a cohort of 110,447 singleton, term pregnancies, we aimed to validate the previously proposed customized standard of large-for-gestational-age (LGA) birthweight, derive an additional customized LGA model excluding maternal weight, and evaluate the association between differing definitions of customized LGA and perinatal morbidities. STUDY DESIGN Three customized LGA classifications, in addition to a population-based 90th percentile, were made according to the principals described by Gardosi: (1) customized LGA using Gardosis previously published coefficients (LGA-Gardosi), (2) customized LGA using coefficients derived by a similar method but from our larger cohort, and (3) derived without customization for maternal weight. Associations between the LGA classifications and various perinatal morbidity outcomes were evaluated. RESULTS Coefficients derived here for physiologic and pathologic effects on birthweight were similar to those previously reported by Gardosi. Customized LGA (any method) generally identified more births to younger, nonwhite, nulliparous mothers with female neonates of lower birthweight compared with population-based LGA. Rates of maternal and neonatal morbidity were greatest in births classified by both population-based LGA and customized LGA (any method). However, the model that excluded customization for maternal weight, revealed a greater proportion of women previously unidentified by population-based LGA who were more frequently black (40% vs 25%) and obese (30% vs 5.1%), along with greater rates of shoulder dystocia, neonatal intensive care unit admission and neonatal respiratory complications, than with LGA-Gardosi. CONCLUSION The use of customized methods of defining LGA was not decisively superior compared with population-based LGA, but custom LGA may be improved by modification of the parameters included in customization.

Perceived stress, reproductive hormones, and ovulatory function: a prospective cohort study

Background: Stress has been shown to suppress ovulation in experimental models, but its effect on human reproduction at the population level is unclear. Methods: Healthy women (n = 259), aged 18–44 years from Western New York, were followed for 2 menstrual cycles (2005–2007). Women completed daily perceived stress assessments, a 4-item Perceived Stress Scale (PSS-4) up to 4 times each cycle, and a 14-item PSS at baseline. Mixed model analyses were used to assess effects of stress on log reproductive hormone concentrations and sporadic anovulation. Results: High versus low daily stress was associated with lower estradiol (−9.5% [95% confidence interval (CI) = −15.6% to −3.0%]), free estradiol (−10.4% [−16.5% to −3.9%]), and luteinizing hormone (−14.8% [−21.3% to −7.7%]) and higher follicle-stimulating hormone (6.2% [95% CI = 2.0% to 10.5%]) after adjusting for age, race, percent body fat, depression score, and time-varying hormones and vigorous exercise. High versus low daily stress was also associated with lower luteal progesterone (−10.4% [95% CI = −19.7% to −0.10%]) and higher odds of anovulation (adjusted odds ratio = 2.2 [95% CI = 1.0 to 4.7]). For each unit increase in daily stress level, women had a 70% higher odds of an anovulatory episode (odds ratio = 1.7 [1.1 to 2.4]). Similar but attenuated results were found for the association between the PSS-4 and reproductive hormones, while null findings were found for the baseline PSS. Conclusion: Daily perceived stress does appear to interfere with menstrual cycle function among women with no known reproductive disorders, warranting further research to explore potential population-level impacts and causal biologic mechanisms.