Urinary oestrogen patterns in long follicular phases

Leveraging External Validation Data: The Challenges of Transporting Measurement Error Parameters

Approaches to address measurement error frequently rely on validation data to estimate measurement error parameters (e.g., sensitivity and specificity). Acquisition of validation data can be costly, thus secondary use of existing data for validation is attractive. To use these external validation data, however, we may need to address systematic differences between these data and the main study sample. Here, we derive estimators of the risk and the risk difference that leverage external validation data to account for outcome misclassification. If misclassification is differential with respect to covariates that themselves are differentially distributed in the validation and study samples, the misclassification parameters are not immediately transportable. We introduce two ways to account for such covariates: (1) standardize by these covariates or (2) iteratively model the outcome. If conditioning on a covariate for transporting the misclassification parameters induces bias of the causal effect (e.g., M-bias), the former but not the latter approach is biased. We provide proof of identification, describe estimation using parametric models, and assess performance in simulations. We also illustrate implementation to estimate the risk of preterm birth and the effect of maternal HIV infection on preterm birth. Measurement error should not be ignored and it can be addressed using external validation data via transportability methods.

Ovarian Reserve Biomarkers and Menstrual Cycle Length in a Prospective Cohort Study

CONTEXT

While age-related changes in menstrual cycle length are well known, it is unclear whether anti-Müllerian (AMH) or other ovarian reserve biomarkers have a direct association with cycle length.

OBJECTIVE

To determine the association between biomarkers of ovarian reserve and menstrual cycle length.

METHODS

Secondary analysis using data from time to conceive (TTC), a prospective time to pregnancy cohort study. The age-independent association between cycle length and biomarkers of ovarian reserve was analyzed using linear mixed and marginal models. Study participants were TTC-enrolled women aged 30-44 years with no history of infertility who were attempting to conceive for <3 months were enrolled. Serum AMH, follicle-stimulating hormone, and inhibin B levels were measured on cycle day 2, 3, or 4. Participants recorded daily menstrual cycle data for ≤4 months. The primary outcome was menstrual cycle length; follicular and luteal phase lengths were secondary outcomes.

RESULTS

Multivariable analysis included 1880 cycles from 632 women. Compared with AMH levels of 1.6 to 3.4 ng/mL, women with AMH <1.6 ng/mL had cycles and follicular phases that were 0.98 (95% CI -1.46, -0.50) and 1.58 days shorter (95% CI -2.53, -0.63), respectively, while women with AMH >8 ng/mL had cycles that were 2.15 days longer (95% CI 1.46, 2.83), follicular phases that were 2 days longer (95% CI 0.77, 3.24), and luteal phases that were 1.80 days longer (95% CI 0.71, 2.88).

CONCLUSION

Increasing AMH levels are associated with longer menstrual cycles due to both a lengthening of the follicular and the luteal phase independent of age.

25-Hydroxyvitamin D and Long Menstrual Cycles in a Prospective Cohort Study

BACKGROUND

Vitamin D insufficiency is associated with subfertility and prolonged estrus cycles in animals, but humans have not been well studied.

METHODS

A prospective time-to-pregnancy study, Time to Conceive (2010-2015), collected up to 4 months of daily diary data. Participants were healthy, late reproductive-aged women in North Carolina who were attempting pregnancy. We examined menstrual cycle length as a continuous variable and in categories: long (35+ days) and short (≤25 days). Follicular phase length and luteal phase length were categorized as long (18+ days) or short (≤10 days). We estimated associations between those lengths and serum 25-hydroxyvitamin D (25[OH]D) using linear mixed models and marginal models.

RESULTS

There were 1,278 menstrual cycles from 446 women of whom 5% were vitamin D deficient (25[OH]D, <20 ng/ml), 69% were between 20 and 39 ng/ml, and 26% were 40 ng/ml or higher. There was a dose-response association between vitamin D levels and cycle length. Compared with the highest 25(OH)D level (≥40 ng/ml), 25(OH)D deficiency was associated with almost three times the odds of long cycles (adjusted odds ratio [aOR] = 2.8 [95% confidence interval (CI) = 1.0, 7.5]). The aOR was 1.9 (1.1, 3.5) for 20 to <30 ng/ml. The probability of a long follicular phase and the probability of a short luteal phase both increased with decreasing 25(OH)D.

CONCLUSIONS

Lower levels of 25(OH)D are associated with longer follicular phase and an overall longer menstrual cycle. Our results are consistent with other evidence supporting vitamin D's role in the reproductive axis, which may have broader implications for reproductive success.

Menstrual cycle characteristics and steroid hormone, prolactin, and growth factor levels in premenopausal women

PURPOSE

Menstrual cycle characteristics are markers of endocrine milieu. However, associations between age at menarche and adulthood sex steroid hormone levels have been inconsistent, and data on menstrual characteristics and non-sex steroid hormones are sparse.

METHODS

We assessed the relations of menstrual characteristics with premenopausal plasma sex steroid hormones, sex hormone binding globulin (SHBG), prolactin, and growth factors among 2,745 premenopausal women (age 32-52) from the Nurses' Health Study II. Geometric means and tests for trend were calculated using multivariable general linear models.

RESULTS

Early age at menarche was associated with higher premenopausal early-follicular free estradiol (percent difference < 12 vs. > 13 years = 11%), early-follicular estrone (7%), luteal estrone (7%), and free testosterone (8%) (all p _trend < 0.05). Short menstrual cycle length at age 18-22 was associated with higher early-follicular total (< 26 vs. > 39 days = 18%) and free estradiol (16%), early-follicular estrone (9%), SHBG (7%), lower luteal free estradiol (- 14%), total (- 6%), and free testosterone (- 15%) (all p _trend < 0.05). Short adult menstrual length was associated with higher early-follicular total estradiol (< 26 vs. > 31 days = 14%), SHBG (10%), lower luteal estrone (- 8%), progesterone (- 9%), total (- 11%) and free testosterone (- 25%), and androstenedione (- 14%) (all p _trend < 0.05). Irregularity of menses at 18-22 was associated with lower early-follicular total (irregular vs. very regular = - 14%) and free estradiol (- 14%), and early-follicular estrone (- 8%) (All p _trend < 0.05). Irregularity of adult menstrual cycle was associated with lower luteal total estradiol (irregular vs. very regular = - 8%), SHBG (- 3%), higher total (8%), and free testosterone (11%) (all p _trend < 0.05).

CONCLUSIONS

Early-life and adulthood menstrual characteristics are moderately associated with mid-to-late reproductive year's hormone concentrations. These relations of menstrual characteristics with endogenous hormone levels could partially account for associations between menstrual characteristics and reproductive cancers or other chronic diseases.

Effect of Air Pollution on Menstrual Cycle Length-A Prognostic Factor of Women's Reproductive Health

Air pollution can influence women's reproductive health, specifically menstrual cycle characteristics, oocyte quality, and risk of miscarriage. The aim of the study was to assess whether air pollution can affect the length of the overall menstrual cycle and the length of its phases (follicular and luteal). Municipal ecological monitoring data was used to assess the air pollution exposure during the monitored menstrual cycle of each of 133 woman of reproductive age. Principal component analyses were used to group pollutants (PM10, SO₂, CO, and NOx) to represent a source-related mixture. PM10 and SO₂ assessed separately negatively affected the length of the luteal phase after standardization (b = -0.02; p = 0.03; b = -0.06; p = 0.02, respectively). Representing a fossil fuel combustion emission, they were also associated with luteal phase shortening (b = -0.32; p = 0.02). These pollutants did not affect the follicular phase length and overall cycle length, neither in single- nor in multi-pollutant models. CO and NOx assessed either separately or together as a traffic emission were not associated with overall cycle length or the length of cycle phases. Luteal phase shortening, a possible manifestation of luteal phase deficiency, can result from fossil fuel combustion. This suggests that air pollution may contribute to fertility problems in women.

Increasing serum 25-hydroxyvitamin D is associated with reduced odds of long menstrual cycles in a cross-sectional study of African American women

OBJECTIVE

To examine the association between serum 25-hydroxyvitamin D [25(OH)D] and menstrual cycle length and regularity.

DESIGN

Community-based, cross-sectional study of serum 25(OH)D (adjusted for seasonal differences in timing of blood draw) and menstrual cycle length. Women aged 23-34 years reported their gynecologic history. Menstrual cycles were described with four independent categories (normal, short, long, irregular). We used polytomous logistic regression to estimate the association between a doubling of seasonally adjusted 25(OH)D and the odds of each cycle category.

SETTING

Not applicable.

PATIENT(S)

A total of 1,102 African American women.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Self-reported menstrual cycle length over the previous 12 months, excluding women who were using cycle-regulating medications over the entire year. Women who reported that their cycles were "too irregular to estimate" were classified as having irregular cycles. A typical cycle length of <27 days was considered "short," >34 days was "long," and 27-34 days was "normal."

RESULT(S)

The median 25(OH)D level was 14.7 ng/mL (interquartile range, 10.9-19.6 ng/mL). A doubling of 25(OH)D was associated with half the odds of having long menstrual cycles: adjusted odds ratio (aOR) 0.54, 95% confidence interval (CI) 0.32-0.89. 25-Hydroxyvitamin D was not associated with the occurrence of short (aOR 1.03, 95% CI 0.82-1.29) or irregular (aOR 1.46, 95% CI 0.88-2.41) menstrual cycles. Results were robust to several sensitivity analyses.

CONCLUSION(S)

These findings suggest that vitamin D status may influence the menstrual cycle and play a role in ovarian function. Further investigation of 25(OH)D and ovarian hormones, and prospective studies of 25(OH)D and cycle length, are needed.

MitoAge: a database for comparative analysis of mitochondrial DNA, with a special focus on animal longevity

Mitochondria are the only organelles in the animal cells that have their own genome. Due to a key role in energy production, generation of damaging factors (ROS, heat), and apoptosis, mitochondria and mtDNA in particular have long been considered one of the major players in the mechanisms of aging, longevity and age-related diseases. The rapidly increasing number of species with fully sequenced mtDNA, together with accumulated data on longevity records, provides a new fascinating basis for comparative analysis of the links between mtDNA features and animal longevity. To facilitate such analyses and to support the scientific community in carrying these out, we developed the MitoAge database containing calculated mtDNA compositional features of the entire mitochondrial genome, mtDNA coding (tRNA, rRNA, protein-coding genes) and non-coding (D-loop) regions, and codon usage/amino acids frequency for each protein-coding gene. MitoAge includes 922 species with fully sequenced mtDNA and maximum lifespan records. The database is available through the MitoAge website (www.mitoage.org or www.mitoage.info), which provides the necessary tools for searching, browsing, comparing and downloading the data sets of interest for selected taxonomic groups across the Kingdom Animalia. The MitoAge website assists in statistical analysis of different features of the mtDNA and their correlative links to longevity.

Regulation of DNA replication at the end of the mitochondrial D-loop involves the helicase TWINKLE and a conserved sequence element

The majority of mitochondrial DNA replication events are terminated prematurely. The nascent DNA remains stably associated with the template, forming a triple-stranded displacement loop (D-loop) structure. However, the function of the D-loop region of the mitochondrial genome remains poorly understood. Using a comparative genomics approach we here identify two closely related 15 nt sequence motifs of the D-loop, strongly conserved among vertebrates. One motif is at the D-loop 5'-end and is part of the conserved sequence block 1 (CSB1). The other motif, here denoted coreTAS, is at the D-loop 3'-end. Both these sequences may prevent transcription across the D-loop region, since light and heavy strand transcription is terminated at CSB1 and coreTAS, respectively. Interestingly, the replication of the nascent D-loop strand, occurring in a direction opposite to that of heavy strand transcription, is also terminated at coreTAS, suggesting that coreTAS is involved in termination of both transcription and replication. Finally, we demonstrate that the loading of the helicase TWINKLE at coreTAS is reversible, implying that this site is a crucial component of a switch between D-loop formation and full-length mitochondrial DNA replication.

Differences in ovarian hormones in relation to parity and time since last birth

OBJECTIVE

To examine ovarian function in relation to parity and time since last birth.

DESIGN

Cross-sectional study.

SETTING

Health-care program in California.

PATIENT(S)

346 naturally cycling women, aged 18 to 39 years.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Mean follicular urinary estradiol metabolite concentration (E1C) (cycle days -8 to -1), mean luteal progesterone metabolite concentration (PdG) (days 0 to +10), and cycle phase lengths in ovulatory cycles.

RESULT(S)

After the women had collected daily urine samples for up to eight menstrual cycles, we measured the E1C and PdG using enzyme-linked immunoassay. The cycle phase lengths were calculated from the hormone profiles and daily diaries. Women who had given birth within the previous 3 years had lower E1C than the nulliparous women and women who last given birth >3 years earlier. Among the parous women, E1C was positively associated with the time since last birth. Women who last gave birth >3 years earlier had longer follicular phases than the nulliparous women. There were no associations between parity and PdG or luteal phase length.

CONCLUSION(S)

Our cross-sectional data suggest that ovarian function differs in nulliparous and parous women and is positively associated with the time since last birth. Longitudinal research is needed to explore within-woman changes in ovarian function prepartum and postpartum.

The control region of mitochondrial DNA shows an unusual CpG and non-CpG methylation pattern

DNA methylation is a common epigenetic modification of the mammalian genome. Conflicting data regarding the possible presence of methylated cytosines within mitochondrial DNA (mtDNA) have been reported. To clarify this point, we analysed the methylation status of mtDNA control region (D-loop) on human and murine DNA samples from blood and cultured cells by bisulphite sequencing and methylated/hydroxymethylated DNA immunoprecipitation assays. We found methylated and hydroxymethylated cytosines in the L-strand of all samples analysed. MtDNA methylation particularly occurs within non-C-phosphate-G (non-CpG) nucleotides, mainly in the promoter region of the heavy strand and in conserved sequence blocks, suggesting its involvement in regulating mtDNA replication and/or transcription. We observed DNA methyltransferases within the mitochondria, but the inactivation of Dnmt1, Dnmt3a, and Dnmt3b in mouse embryonic stem (ES) cells results in a reduction of the CpG methylation, while the non-CpG methylation shows to be not affected. This suggests that D-loop epigenetic modification is only partially established by these enzymes. Our data show that DNA methylation occurs in the mtDNA control region of mammals, not only at symmetrical CpG dinucleotides, typical of nuclear genome, but in a peculiar non-CpG pattern previously reported for plants and fungi. The molecular mechanisms responsible for this pattern remain an open question.

Darwin's legacy: an evolutionary view of women's reproductive and sexual functioning

On the Origin of species, published just over 150 years ago, has deeply influenced thinking in both scientific and wider communities. Darwin's legacy includes recognition of the fact that all organisms evolve; that variation within and between species is natural and normal; and that an evolutionary approach to understanding the sources and consequences of this variation comprises theoretical frameworks, testable hypotheses, and rigorously collected evidence. With an eye toward facilitating communication and productive collaboration among researchers from different intellectual traditions who nonetheless share a common interest in women's reproductive and sexual functioning, we discuss evolutionary concepts and models, summarize the known variability in ovarian functioning and consider the implications of this variability for conducting sex research, and evaluate the relative merits of various biomarkers that serve as proxy measurements of a woman's reproductive and hormonal status. With these perspectives and methods from reproductive ecology at hand, we examine several contentious issues: the links between hormones and sexuality in premenopausal and perimenopausal women, the causes of premenstrual syndrome, and the existence (or not) of menstrual synchrony. In none of these cases is as much known as is often claimed. In each, there are abundant opportunities for innovative, albeit challenging, research.

A factor analysis approach to examining relationships among ovarian steroid concentrations, gonadotrophin concentrations and menstrual cycle length characteristics in healthy, cycling women

STUDY QUESTION

How are ovarian steroid concentrations, gonadotrophins and menstrual cycle characteristics inter-related within normal menstrual cycles?

SUMMARY ANSWER

Within cycles, measures of estradiol production are highly related to one another, as are measures of progesterone production; however, the two hormones also show some independence from one another, and measures of cycle length and gonadotrophin concentrations show even greater independence, indicating minimal integration within cycles.

WHAT IS KNOWN ALREADY

The menstrual cycle is typically conceptualized as a cohesive unit, with hormone levels, follicular development and ovulation all closely inter-related within a single cycle. Empirical support for this idea is limited, however, and to our knowledge, no analysis has examined the relationships among all of these components simultaneously.

STUDY DESIGN, SIZE, DURATION

A total of 206 healthy, cycling Norwegian women participated in a prospective cohort study (EBBA-I) over the duration of a single menstrual cycle. Of these, 192 contributed hormonal and cycle data to the current analysis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Subjects provided daily saliva samples throughout the menstrual cycle from which estradiol and progesterone concentrations were measured. FSH and LH concentrations were measured in serum samples from three points in the same menstrual cycle and cycle length characteristics were calculated based on hormonal data and menstrual records. A factor analysis was conducted to examine the underlying relationships among 22 variables derived from the hormonal data and menstrual cycle characteristics.

MAIN RESULTS AND THE ROLE OF CHANCE

Six rotated factors emerged, explaining 80% of the variance in the data. Of these, factors representing estradiol and progesterone concentrations accounted for 37 and 13% of the variance, respectively. There was some association between measures of estradiol and progesterone production within cycles; however, cycle length characteristics and gonadotrophin concentrations showed little association with any measure of ovarian hormone concentrations.

LIMITATIONS, REASONS FOR CAUTION

Our summary measures of ovarian hormones may be imprecise in women with extremely long or short cycles, which could affect the patterns emerging in the factor analysis. Given that we only had data from one cycle on each woman, we cannot address how cycle characteristics may covary within individual women across multiple cycles.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings are generalizable to other healthy populations with typical cycles, however, may not be applicable to cycles that are anovulatory, extreme in length or otherwise atypical. The results support previous findings that measures of estradiol production are highly correlated across the cycle, as are measures of progesterone production. Estradiol and progesterone concentrations are associated with one another, furthermore. However factor analysis also revealed more complex underlying patterns in the menstrual cycle, highlighting the fact that gonadotrophin concentrations and cycle length characteristics are virtually independent of ovarian hormones. These results suggest that despite integration of follicular and luteal ovarian steroid production across the cycle, cycle quality is a multi-faceted construct, rather than a single dimension.

STUDY FUNDING/COMPETING INTEREST(S)

The EBBA-I study was supported by a grant from the Norwegian Cancer Society (49 258, 05087); Foundation for the Norwegian Health and Rehabilitation Organizations (59010-2000/2001/2002); Aakre Foundation (5695-2000, 5754-2002) and Health Region East. The current analyses were completed under funding from the National Institutes of Health (K12 ES019852). No competing interests declared.

The utility of menstrual cycle length as an indicator of cumulative hormonal exposure

CONTEXT

Associations between menstrual cycle length and chronic diseases are hypothesized to be due to differences in underlying hormonal patterns.

OBJECTIVE

The aim of the study was to evaluate the association between menstrual cycle length and the hormonal profile and anovulation.

DESIGN AND SETTING

We conducted a prospective cohort study at the University at Buffalo from 2005 to 2007.

PARTICIPANTS

We recruited 259 healthy, regularly menstruating women aged 18-44 yr.

MAIN OUTCOME MEASURES

Cycle length was observed for up to two cycles. Serum estradiol, progesterone, LH, and FSH were measured up to eight times per cycle for up to two cycles.

RESULTS

Women with short cycles (<26 d) had higher FSH concentrations during menses and in the late luteal phase, higher follicular estradiol concentrations, and lower LH concentrations across the cycle. Among women with longer cycles (>35 d), estradiol and LH peaks occurred on average about 3 d later, and FSH peaks about 1 d later compared to women with normal-length cycles. Both short and long cycles, compared with normal-length cycles, had an increased probability of anovulation. In general, per-cycle exposure to hormones was less in short cycles based on the area under the curve, although over time the cumulative exposure to estradiol would be greater for women with short cycles.

CONCLUSIONS

Short ovulatory cycles were associated with higher follicular phase estradiol, an earlier rise in FSH, and an increased risk of anovulation. These results suggest that menstrual cycle length may be a relevant indicator of estradiol exposure and risk of anovulation among regularly cycling women.

Hypoestrogenic "inactive phases" at the start of the menstrual cycle: changes with age and reproductive stage, and relationship to follicular depletion

OBJECTIVE

To investigate hypoestrogenic "inactive phases" (IP) in the follicular phase of the menstrual cycle, with respect to age, reproductive stage, and follicular depletion.

DESIGN

Analysis of prospectively collected menstrual bleed and estrone-3-glucuronide data.

SETTING

Center for Population and Health, Georgetown University.

PATIENT(S)

White women (n = 88, aged 25-59 years, mean = 44.7 years) from the population-based Biodemographic Models of Reproductive Aging (BIMORA) project.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

The IP durations by age and reproductive stage. Estimated follicular depletion rate based on IP durations.

RESULT(S)

Mean IP duration and variability decreased and then increased with age/reproductive stage. The proportion of very short (≤ 1 day) IP durations increased and then decreased with age/stage. Long IPs occurred most, but not exclusively, in the oldest age/latest stage. Follicular depletion rate estimates were a plausible 2%-4% per year of age, but these models were a poor fit because IP durations did not consistently increase across ages/stages.

CONCLUSION(S)

Follicular depletion models alone do not explain the observed pattern of IPs. Our data suggest that IPs reflect both follicular depletion and hyperstimulation in premenopausal and perimenopausal women. Knowledge of underlying IP patterns in the menstrual cycle could inform decisions about hormone sampling and contraception during the perimenopause.

Studying forced expiratory volume at 1 second over menstrual segments in asthmatic and non-asthmatic women: assessing protocol feasibility

Background

Sex hormones may play an important role in observed gender differences in asthma incidence and severity, as well as in the observed changes in asthma symptoms during times of hormonal fluctuation (i.e.; premenstrual, pregnancy, etc.). This pilot study sought to demonstrate the feasibility of data collection methods to investigate the effects of sex hormones on lung function in women.

Findings

A cohort of 13 women (6 with and 7 without prior asthma diagnoses) who were having menstrual periods and were not taking hormones collected urine samples daily for measurement of estrogen (estrone E1C) and progesterone (Pregnanediol-glucuronide PDG) metabolites over the course of a menstrual segment (bleeding episode plus the following bleeding-free interval). Hormones were used to estimate menstrual segment phase (follicular versus luteal) based on a published algorithm. Daily bleeding and FEV1 measurements were recorded and percent predicted FEV1 was calculated. Percent predicted FEV1 decreased over the course of the follicular but not the luteal phase. More specifically, among women without a prior asthma diagnosis, the E1C/PDG ratio and E1C and PDG were individually associated with FEV1 in the follicular phase. No associations were found between hormones and percent predicted FEV1 in the luteal phase or among asthmatic women. E1C was associated with FEV1 in the five days before bleeding onset only among non-asthmatic women.

Discussion

A study of contiguous daily hormones and symptoms over menstrual segments from a large group of women with and without asthma is needed to better determine within-woman cyclicity of the observed patterns.

Behavioural and biological determinants of human sex ratio at birth

The human sex ratio SR (proportion male) at birth has been reported to vary with many variables. The explanation of this variation is not established, but I have hypothesized that it is partially caused by the hormonal concentrations of both parents around the time of conception. The present note suggests how this hypothesis might accommodate recent sex ratio findings relating to 'psychosexual restriction', female genital cutting, sexes of prior sibs, finger length ratios, the autism spectrum disorder, parental occupation and maternal eating disorders. Tests of such suggestions are offered, and it is hypothesized that: (a) in women, Manning's R (the ratio of the lengths of the 2nd and 4th digits) is positively correlated with offspring sex ratio (proportion male); (b) women who have undergone female genital cutting (FGC) have high androgen levels; (c) offspring sex ratio correlates positively with 'masculinity' of parental occupation, the correlation being mediated by testosterone levels. It is noted that the lines of evidence for three hypotheses (James', Manning's and Baron-Cohen's) are mutually supportive.

Follicular growth pattern in normal-cycling Brazilian adolescents

OBJECTIVE

To examine the follicular growth characteristics in normal Brazilian adolescents.

DESIGN

Descriptive study.

SETTING

Adolescent clinic in a university hospital.

PATIENT(S)

Healthy normal cycling adolescents.

INTERVENTION(S)

Endovaginal ultrasound; blood samples for hormone measurement.

MAIN OUTCOME MEASURE(S)

Follicular-phase length, follicular growth rate.

RESULT(S)

The menstrual-cycle interval was 29.5 +/- 1.6 days. Sixty-five percent of adolescents had follicular-phase length of <or=16 days (group 1), and nearly 35% had follicular-phase length of >16 days (group 2). In the early follicular phase, the levels of FSH, LH, and E(2) were 5.1 mIU/mL, 3.0 mIU/mL, and 28.3 pg/mL, respectively. There was a mild negative correlation between FSH and follicular-phase length across the whole cohort (r = -0.464), but after analysis as a separate group, the correlation was present only in those adolescents with follicular phase lasting </=16 days. There was no correlation between LH or E(2) levels and the follicular-phase length in either group. There was good correlation between the follicular size and follicular-phase length in both groups of adolescents. The follicular growth rate was 1.11 +/- 0.05 mm/d across the whole cohort, 1.33 +/- 0.05 mm/d in the adolescents with follicular-phase length of <or=16 days, and 0.88 +/- 0.06 mm/d in those in whom the follicular phase lasted >16 days.

CONCLUSION(S)

A long follicular phase is common in normal-cycling, healthy adolescents as a consequence of slow follicular growth rate.

Characterization of mitochondrial replication and transcription control during rat early development in vivo and in vitro

In vitroculture (IVC), used in assisted reproductive technologies, is a major environmental stress on the embryo. To evaluate the effect of IVC on mitochondrial transcription and the control of mtDNA replication, we measured the mtDNA copy number and relative amount of mRNA for mitochondrial-related genes in individual rat oocytes, zygotes and embryos using real-time PCR. The average mtDNA copy number was 147 600 (±3000) in metaphase II oocytes. The mtDNA copy number was stable throughoutin vivoearly development and IVC induced an increase in mtDNA copy number from the 8-cell stage onwards.GapdmRNA levels vary during early development and IVC did not change the patterns of these housekeeping gene transcripts.PolrmtmRNA levels did not vary during early development up to the morula stage but increased at the blastocyst stage. IVC induced the up-regulation ofPolrmtmRNA, one of the key genes regulating mtDNA transcription and replication, at the blastocyst stage. An increase inmt-Nd4mRNA preceded the blastocyst-related event observed in nuclear-encodedGapdandPolrmt, suggesting that the expression of mitochondrial encoded genes is controlled differently from nuclear encoded genes. We conclude that the IVC system can perturb mitochondrial transcription and the control of mtDNA replication in rat embryos. This perturbation of mtDNA regulation may be responsible for the abnormal physiology, metabolism and viability ofin vitro-derived embryos.

CYP17 genotype predicts serum hormone levels among pre-menopausal women

BACKGROUND

CYP17, which encodes cytochrome P450c17alpha, mediates both steroid 17alpha-hydroxylase and 17,20-lyase activities, and is essential for the production of glucocorticoids and sex steroids. There is evidence that a common polymorphism in CYP17 (T27C) is associated with estrogen levels, making it a potential marker of disease risk.

METHODS

This is the first study to examine the relationship between CYP17 and estradiol (E2) using serum sampled exclusively from the early follicular phase of the menstrual cycle. We assessed the relationship between CYP17 and serum hormone levels, menstrual cycle length, bleed length, and age at menarche in 164 pre-menopausal women.

RESULTS

Among women with body mass index (BMI) < or =25 kg/m2, those with the TC and CC genotypes had 19 and 42% higher E2 (P for trend 0.007) and 14 and 30% higher dehydroepiandrosterone sulphate respectively (P for trend 0.10) than women with the TT genotype. Androstenedione levels did not differ between genotypes. Among women with BMI >25 kg/m2, hormone levels did not differ by genotype. Women with the C allele were also more likely to have menstrual cycle lengths <27 days [odds ratio (OR) for TC=2.36, 95% confidence interval (CI)=1.24-4.52; OR for CC=5.59, 95% CI=1.53-20.43 compared to TT]. CYP17 genotype was not associated with menstrual bleed length or age at menarche.

CONCLUSION

The CYP17 T27C polymorphism may be a marker of endocrine function.

5-Fluoro-2'-deoxyuridine has effects on mitochondria in CEM T-lymphoblast cells

Fluoropyrimidines are useful anticancer agents and the compound 5-fluoro-2'-deoxyuridine (FdUrd) plays an important role in chemotherapy of colon cancers. Several nucleoside analogs, such as 3'-azido-2',3'-dideoxythymidine (AZT) and 2',3'-dideoxycytidine (ddC), can be incorporated into and cause depletion of mitochondrial DNA (mtDNA). These drugs are known to cause mitochondrial toxicity after prolonged treatment in patients. In this study we demonstrate that FdUrd reduces the mtDNA content and the expression level of the mtDNA encoded cytochrome c oxidase (COX II) in a CEM T-lymphoblastic cell line.

Ovarian hormones in premenopausal women: variation by demographic, reproductive and menstrual cycle characteristics

BACKGROUND

Ovarian function influences many areas of concern in women's health, including breast cancer and other chronic diseases. However, ovarian function has been little studied in healthy, premenopausal women, partly because of cyclical variation.

METHODS

We measured biomarkers of ovarian function (daily urinary metabolites of estrogen and progesterone) among 411 women age 18-39 years, who were Kaiser Permanente members in Northern California in 1990-1991. We have summarized the hormone metabolite levels of about 1,500 cycles and examined their associations with demographic and menstrual cycle characteristics.

RESULTS

Cycles with a short follicular phase showed elevations of 10-13% in both baseline (days 1-5) and average follicular-phase estrogen metabolite levels, as well as some elevations in progesterone metabolites. Progesterone metabolite levels were directly related to the length of the luteal phase. Compared with whites, Hispanics had estrogen metabolite levels that were 7-13% higher in the follicular and luteal phases, whereas nonwhite, non-Hispanic women (primarily Asians) had slightly lower levels. Generally, women with a prior pregnancy or those with a later age at menarche had lower estrogen metabolite levels, whereas women with prior induced abortions had higher levels. Luteal-phase progesterone metabolite levels tended to be lower among women who were overweight, were less educated, were older at their first livebirth, or had an induced abortion.

CONCLUSIONS

Some menstrual cycle characteristics provide a crude surrogate of the hormonal milieu, particularly luteal-phase length and progesterone levels. Hormone levels varied by reproductive characteristics, potentially explaining their relevance to breast cancer risk.

Mean versus individual hormonal profiles in the menstrual cycle

OBJECTIVE

To evaluate hormonal profiles of normal menstrual cycles.

DESIGN

Prospective, descriptive study of a case series.

SETTING

University-based natural family planning center.

PATIENT(S)

Twenty-five natural family planning users for three or more cycles (n = 78). These women were healthy, contraception-free, parous, with regular ovulatory cycles.

INTERVENTION(S)

Immunoassays for estrone glucuronide, LH, and pregnanediol glucuronide were done in daily timed and measured samples of early morning urine.

MAIN OUTCOME MEASURE(S)

Estrone glucuronide, LH, and pregnanediol glucuronide levels were measured during the menstrual cycle.

RESULT(S)

All cycles showed an ovulatory pattern configuring classic hormonal mean curves. Most (77%) differed from the mean curve pattern. All had estrone glucuronide peaks, LH peaks, and pregnanediol glucuronide increases. Estrone glucuronide and LH peaks were not always clear; some lasted more than 1 day (long peak: estrone glucuronide 19%, LH 9%) or fluctuated (double peak: estrone glucuronide 4%, LH 6%; small LH peak: 19%). There were also prepeak estrone glucuronide surges, and pre- and postpeak LH surges. Pregnanediol glucuronide increased more clearly (6% fluctuated 1 day). Some women had repeated cycles with long estrone glucuronide peaks (16%) and fluctuations in LH surge (44%).

CONCLUSION(S)

Normal menstrual cycle hormonal profiles generally differ from mean curves, which are usually considered standard.

Interactions of the female hormonal environment, susceptibility to viral infections, and disease progression

Sex hormones influence susceptibility and disease predisposition for many genital tract infections. This review describes the mechanisms by which sex steroids affect mucosal immunity, with particular reference to human immunodeficiency virus (HIV) and genital herpes, and the stage-specific effects of hormonal contraception on human papillomavirus (HPV) infection. Estrogen's role is important in the early stages of several infections as it stimulates antibody- and cell-mediated immune responses. There is increased expression of some cytokines in peripheral blood and vaginal fluids during the follicular phase of the menstrual cycle and with use of hormonal contraception. Whether estrogen exerts a protective or deleterious influence depends on the infecting organism and stage of infection or disease. Estrogen apparently reduces susceptibility to primary HPV infection but in the event of persistent HPV infection, sex steroid hormones (estrogen and/or progesterone) are associated with progression to cervical cancer. It is important that these stage-specific effects are better described because most vaccines will try to prevent either infection or disease. Clinicians with patients at high risk of sexually transmitted infections, especially HIV, require better information on the risks associated with different hormonal contraceptive regimes.

DNA fingerprinting of sister blastomeres from human IVF embryos

BACKGROUND

Previously published single cell DNA fingerprinting systems have been plagued by high rates of allele drop-out (ADO) and preferential amplification (PA) preventing clinical application in preimplantation genetic diagnosis.

METHODS

Tetranucleotide microsatellite markers with high heterozygosity, known allelic size ranges and minimal PCR stutter artefacts were selected for chromosomes X, 13, 18 and 21 and optimized in a multiplex fluorescent (FL)-PCR format. FL-PCR products were analysed using the ABI Prism 377 DNA sequenator and Genescan software. Validation of the DNA fingerprinting system was performed on single diploid (n = 50) and aneuploid (n = 25) buccal cells and embryonic blastomeres (n = 21).

RESULTS

The optimized pentaplex PCR DNA fingerprinting system displayed a high proportion of successful amplifications (>91%) and low ADO and PA (<6%) when assessed on 50 human buccal cells. DNA fingerprints of single cells from a subject with Down's syndrome detected the expected tri-allelic pattern for the chromosome 21 marker, confirming trisomy 21. In a blind study on 21 single blastomeres, all embryos were identifiable by their unique DNA fingerprints and shared parental alleles.

CONCLUSIONS

A highly specific multiplex FL-PCR based on the amplification of five highly polymorphic microsatellite markers was developed for single cells. This finding paves the way for the development of a more complex PCR DNA fingerprinting system to assess aneuploidy and single gene mutations in IVF embryos from couples at genetic risk.