Pre-gravid oral contraceptive use and time to pregnancy: a Danish prospective cohort study

Effect of various contraceptives on oocyte yield and maturation in patients undergoing planned oocyte cryopreservation

RESEARCH QUESTION

Do the various forms of hormonal and non-hormonal contraceptives have any association with ovarian stimulation outcomes, such as oocyte yield and maturation, in patients undergoing planned oocyte cryopreservation (POC)?

DESIGN

This retrospective cohort study included all patients who underwent POC cycles between 2011 and 2023. The use of types of contraception before a POC cycle was recorded. The study evaluated the median number of cumulus-oocyte complexes obtained after vaginal oocyte retrieval and the proportion of metaphase II oocytes that underwent vitrification among all the cohorts.

RESULTS

A total of 4059 oocyte freezing cycles were included in the analysis. Eight types of contraceptive method were recognized in patients undergoing ovarian stimulation: intrauterine device (IUD), copper (n = 84); IUD, levonorgestrel low dose (<52 mg) (n = 37); IUD, levonorgestrel (n = 192); subdermal etonogestrel implant (n = 14); injectable medroxyprogesterone acetate (n = 11); etonogestrel vaginal ring (n = 142); combined oral contraceptive pills (n = 2349); and norelgestromin transdermal patch (n = 10). The control group included patients not using contraceptives or using barrier or calendar methods (n = 1220). Among all the cohorts the median number of cumulus-oocyte complexes retrieved during oocyte retrieval was comparable (P = 0.054), and a significant difference in oocyte maturity rate with median number of vitrified oocytes was found (P = 0.03, P < 0.001, respectively). After adjusting for confounders a multivariate analysis found no association between the type of contraceptive and proportion of metaphase II oocytes available for cryopreservation.

CONCLUSIONS

Among the various forms of contraception, none was shown to have an adverse association with oocyte yield or maturation rate in patients undergoing POC.

Randomised controlled trial of preconception lifestyle intervention on maternal and offspring health in people with increased risk of gestational diabetes: study protocol for the BEFORE THE BEGINNING trial

INTRODUCTION

Gestational diabetes mellitus (GDM) is associated with increased risk for type 2 diabetes in the mother and cardiometabolic diseases in the child. The preconception period is an optimal window to adapt the lifestyle for improved outcomes for both mother and child. Our aim is to determine the effect of a lifestyle intervention, initiated before and continued throughout pregnancy, on maternal glucose tolerance and other maternal and infant cardiometabolic outcomes.

METHODS AND ANALYSIS

This ongoing randomised controlled trial has included 167 females aged 18-39 years old at increased risk for GDM who are contemplating pregnancy. The participants were randomly allocated 1:1 to an intervention or control group. The intervention consists of exercise (volume is set by a heart rate-based app and corresponds to ≥ 1 hour of weekly exercise at ≥ 80% of individual heart rate maximum), and time-restricted eating (≤ 10 hours/day window of energy intake). The primary outcome measure is glucose tolerance in gestational week 28. Maternal and offspring outcomes are measured before and during pregnancy, at delivery, and at 6-8 weeks post partum. Primary and secondary continuous outcome measures will be compared between groups based on the 'intention to treat' principle using linear mixed models.

ETHICS AND DISSEMINATION

The Regional Committees for Medical and Health Research Ethics in Norway has approved the study (REK 143756). The anonymised results will be submitted for publication and posted in a publicly accessible database of clinical study results.

TRIAL REGISTRATION NUMBER

Clinical trial gov NCT04585581.

Preconception contraceptive use and miscarriage: prospective cohort study

Objectives

To evaluate the association between preconception contraceptive use and miscarriage.

Design

Prospective cohort study.

Setting

Residents of the United States of America or Canada, recruited from 2013 until the end of 2022.

Participants

13 460 female identified participants aged 21-45 years who were planning a pregnancy were included, of whom 8899 conceived. Participants reported data for contraceptive history, early pregnancy, miscarriage, and potential confounders during preconception and pregnancy.

Main outcome measure

Miscarriage, defined as pregnancy loss before 20 weeks of gestation.

Results

Preconception use of combined and progestin-only oral contraceptives, hormonal intrauterine devices, copper intrauterine devices, rings, implants, or natural methods was not associated with miscarriage compared with use of barrier methods. Participants who most recently used patch (incidence rate ratios 1.34 (95% confidence interval 0.81 to 2.21)) or injectable contraceptives (1.44 (0.99 to 2.12)) had higher rates of miscarriage compared with recent users of barrier methods, although results were imprecise due to the small numbers of participants who used patch and injectable contraceptives.

Conclusions

Use of most contraceptives before conception was not appreciably associated with miscarriage rate. Individuals who used patch and injectable contraceptives had higher rates of miscarriage relative to users of barrier methods, although these results were imprecise and residual confounding was possible.

Potential biomarkers to predict return to fertility after discontinuation of female contraceptives-looking to the future

Nowadays there are multiple types of contraceptive methods, from reversible to permanent, for those choosing to delay pregnancy. Misconceptions about contraception and infertility are a key factor for discontinuation or the uptake of family planning methods. Regaining fertility (the ability to conceive) after contraceptive discontinuation is therefore pivotal. Technical studies to date have evaluated return to fertility by assessing pregnancy as an outcome, with variable results, or return to ovulation as a surrogate measure by assessing hormone levels (such as progesterone, LH, FSH) with or without transvaginal ultrasound. In general, relying on time to pregnancy as an indicator of return to fertility following contraceptive method discontinuation can be problematic due to variable factors independent of contraceptive effects on fertility, hormone clearance, and fertility recovery. Since the ability to conceive after contraceptive method discontinuation is a critical factor influencing product uptake, it is important to have robust biomarkers that easily and accurately predict the timing of fertility return following contraception and isolate that recovery from extrinsic and circumstantial factors. The main aim of this review is to summarize the current approaches, existing knowledge, and gaps in methods of evaluating return-to-fertility as well as to provide insights into the potential of new biomarkers to more accurately predict fertility restoration after contraceptive discontinuation. Biomarker candidates proposed in this document include those associated with folliculogenesis, cumulus cell expansion, follicular rupture and ovulation, and endometrial transport and receptivity which have been selected and scored on predefined criteria meant to evaluate their probable viability for advancement. The review also describes limitations, regulatory requirements, and a potential path to clinically testing these selected biomarkers. It is important to understand fertility restoration after contraceptive method discontinuation to provide users and health providers with accurate evidence-based information. Predictive biomarkers, if easy and low-cost, have the potential to enable robust evaluation of RTF, and provide potential users the information they desire when selecting a contraceptive method. This could lead to expanded uptake and continuation of modern contraception and inform the development of new contraceptive methods to widen user's family planning choices.

Regulatory T Cell Proportion and Phenotype Are Altered in Women Using Oral Contraception

Regulatory T (Treg) cells are a specialized CD4+ T cell subpopulation that are essential for immune homeostasis, immune tolerance, and protection against autoimmunity. There is evidence that sex-steroid hormones estrogen and progesterone modulate Treg cell abundance and phenotype in women. Since natural oscillations in these hormones are modified by hormonal contraceptives, we examined whether oral contraception (OC) use impacts Treg cells and related T cell populations. T cells were analyzed by multiparameter flow cytometry in peripheral blood collected across the menstrual cycle from healthy women either using OC or without hormonal contraception and from age-matched men. Compared to naturally cycling women, women using OC had fewer Treg cells and an altered Treg cell phenotype. Notably, Treg cells exhibiting a strongly suppressive phenotype, defined by high FOXP3, CD25, Helios, HLADR, CTLA4, and Ki67, comprised a lower proportion of total Treg cells, particularly in the early- and mid-cycle phases. The changes were moderate compared to more substantial differences in Treg cells between women and men, wherein women had fewer Treg cells-especially of the effector memory Treg cell subset-associated with more T helper type 1 (Th1) cells and CD8+ T cells and lower Treg:Th1 cell and Treg:CD8+ T cell ratios than men. These findings imply that OC can modulate the number and phenotype of peripheral blood Treg cells and raise the possibility that Treg cells contribute to the physiological changes and altered disease susceptibility linked with OC use.

Ovulation suppression protects against chromosomal abnormalities in mouse eggs at advanced maternal age

The frequency of egg aneuploidy and trisomic pregnancies increases with maternal age. To what extent individual approaches can delay the "maternal age effect" is unclear because multiple causes contribute to chromosomal abnormalities in mammalian eggs. We propose that ovulation frequency determines the physiological aging of oocytes, a key aspect of which is the ability to accurately segregate chromosomes and produce euploid eggs. To test this hypothesis, ovulations were reduced using successive pregnancies, hormonal contraception, and a pre-pubertal knockout mouse model, and the effects on chromosome segregation and egg ploidy were examined. We show that each intervention reduces chromosomal abnormalities in eggs of aged mice, suggesting that ovulation reduction delays oocyte aging. The protective effect can be partly explained by retention of chromosomal Rec8-cohesin that maintains sister chromatid cohesion in meiosis. In addition, single-nucleus Hi-C (snHi-C) revealed deterioration in the 3D chromatin structure including an increase in extruded loop sizes in long-lived oocytes. Artificial cleavage of Rec8 is sufficient to increase extruded loop sizes, suggesting that cohesin complexes maintaining cohesion restrict loop extrusion. These findings suggest that ovulation suppression protects against Rec8 loss, thereby maintaining both sister chromatid cohesion and 3D chromatin structure and promoting production of euploid eggs. We conclude that the maternal age effect can be delayed in mice. An implication of this work is that long-term ovulation-suppressing conditions can potentially reduce the risk of aneuploid pregnancies at advanced maternal age.

Maternal age at birth and daughter's fecundability

STUDY QUESTION

Do daughters of older mothers have lower fecundability?

SUMMARY ANSWER

In this cohort study of North American pregnancy planners, there was virtually no association between maternal age ≥35 years and daughters' fecundability.

WHAT IS KNOWN ALREADY

Despite suggestive evidence that daughters of older mothers may have lower fertility, only three retrospective studies have examined the association between maternal age and daughter's fecundability.

STUDY DESIGN, SIZE, DURATION

Prospective cohort study of 6689 pregnancy planners enrolled between March 2016 and January 2020.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Pregnancy Study Online (PRESTO) is an ongoing pre-conception cohort study of pregnancy planners (age, 21-45 years) from the USA and Canada. We estimated fecundability ratios (FR) for maternal age at the participant's birth using multivariable proportional probabilities regression models.

MAIN RESULTS AND THE ROLE OF CHANCE

Daughters of mothers ≥30 years were less likely to have previous pregnancies (or pregnancy attempts) or risk factors for infertility, although they were more likely to report that their mother had experienced problems conceiving. The proportion of participants with prior unplanned pregnancies, a birth before age 21, ≥3 cycles of attempt at study entry or no follow-up was greater among daughters of mothers <25 years. Compared with maternal age 25-29 years, FRs (95% CI) for maternal age <20, 20-24, 30-34, and ≥35 were 0.72 (0.61, 0.84), 0.92 (0.85, 1.00), 1.08 (1.00, 1.17), and 1.00 (0.89, 1.12), respectively.

LIMITATIONS, REASONS FOR CAUTION

Although the examined covariates did not meaningfully affect the associations, we had limited information on the participants' mother. Differences by maternal age in reproductive history, infertility risk factors and loss to follow-up suggest that selection bias may partly explain our results.

WIDER IMPLICATIONS OF THE FINDINGS

Our finding that maternal age 35 years or older was not associated with daughter's fecundability is reassuring, considering the trend towards delayed childbirth. However, having been born to a young mother may be a marker of low fecundability among pregnancy planners.

STUDY FUNDING/COMPETING INTEREST(S)

PRESTO was funded by NICHD Grants (R21-HD072326 and R01-HD086742) and has received in-kind donations from Swiss Precision Diagnostics, FertilityFriend.com, Kindara.com, and Sandstone Diagnostics. Dr Wise is a fibroid consultant for AbbVie, Inc.

TRIAL REGISTRATION NUMBER

n/a.

Endocrine disrupting chemicals: strategies to protect present and future generations

Introduction: Endocrine-disrupting chemicals (EDCs) are chemicals that alter the actions of hormones. In the 21^st Century, numerous expert groups of clinicians, scientists, and environmental activists have called for action to protect present and future generations from the harm induced by EDC exposures. These demands for regulatory responses come because of the strong weight of the evidence from epidemiology, wildlife, and controlled laboratory studies.Areas covered: In this review, we examine the conclusions drawn by experts from different scientific and medical disciplines. We also address several areas where recent findings or work has changed the landscape of EDC work including new approaches to identify and evaluate the evidence for EDCs using a key characteristics approach, the need to expand our understanding of vulnerable periods of development, and the increasing concern that traditional methods used to evaluate toxicity of environmental chemicals are insufficient for EDCs and how collaborative science could help to address these gaps.Expert opinion: The science is clear: there is more than enough evidence to demonstrate that EDCs affect the health of humans and wildlife. Waiting to act is a decision that puts the health of current and future generations at risk.

Pregravid contraceptive use and fecundability: prospective cohort study

OBJECTIVE

To evaluate the association between pregravid use of a variety of contraceptive methods and subsequent fecundability.

DESIGN

Prospective cohort study.

SETTING

Denmark and North America, 2007-19.

PARTICIPANTS

17 954 women who had tried to conceive for up to six menstrual cycles at study entry. At baseline, participants reported their contraceptive histories, and personal, medical, and lifestyle characteristics.

MAIN OUTCOME MEASURES

Pregnancy, determined by bimonthly follow-up questionnaires for up to 12 months.

RESULTS

Approximately 38% (n=6735) of participants had recently used oral contraceptives, 13% (n=2398) had used long acting reversible contraceptive methods, and 31% (n=5497) had used barrier methods. Women who had recently stopped using oral contraceptives, the contraceptive ring, and some long acting reversible contraceptive methods experienced short term delays in return of fertility compared with users of barrier methods. Use of injectable contraceptives was associated with decreased fecundability compared with use of barrier methods (fecundability ratio 0.65; 95% confidence interval 0.47 to 0.89). Users of injectable contraceptives had the longest delay in return of normal fertility (five to eight menstrual cycles), followed by users of patch contraceptives (four cycles), users of oral and ring contraceptives (three cycles), and users of hormonal and copper intrauterine devices and implant contraceptives (two cycles). Lifetime length of use of hormonal contraceptive methods was not associated with fecundability.

CONCLUSIONS

Use of some hormonal contraceptive methods was associated with delays in return of fertility, with injectable contraceptives showing the longest delay. The findings indicated little or no lasting effect of long term use of these methods on fecundability.

Oral Contraceptives and Venous Thromboembolism: Focus on Testing that May Enable Prediction and Assessment of the Risk

Combined oral contraceptives (COCs) induce several changes in the levels of coagulation factors. The levels of procoagulant factors are often increased, while levels of anticoagulant factors are decreased. Fibrinolysis is also affected, even if the effect seems to be more counterbalanced by opposite regulation of profibrinolytic and antifibrinolytic factors. These effects on hemostasis are more pronounced with third- or fourth-generation COC compared with second-generation COC. Venous thromboembolism (VTE) risk increases when multiple risk factors, including genetic and environmental, are present simultaneously. COC use causes changes in coagulation that modify the prothrombotic state induced by preexisting hemostatic alterations in a supra-additive manner. Therefore, testing appears to be of importance not only before implementing COC but also to monitor any potential thrombogenicity induced by COC therapy. Inherited genetic factors, such as factor V Leiden, G20210A prothrombin mutation, antithrombin, protein C or protein S deficiencies, non-O blood group, as well as CYP2C9*2 and the rs4379368 mutations, have all been identified as genetic predictive risk factors of VTE in women. Nevertheless, the screening of these genetic biomarkers is not capable of assessing the phenotypic expression of the risk. This review will focus on the different options for screening the thrombogenic status in this population. Specific attention will be given to the endogenous thrombin potential-based activated protein C resistance, a test aiming at assessing the thrombogenicity induced by hormonal therapies and inherited or acquired thrombophilia.

Persistent organic pollutants, pre-pregnancy use of combined oral contraceptives, age, and time-to-pregnancy in the SELMA cohort

BACKGROUND

We are exposed to several chemicals such as persistent organic pollutants (POPs) in our everyday lives. Prior evidence has suggested that POPs may have adverse effects on reproductive function by disrupting hormone synthesis and metabolism. While there is age-related decline of fertility, the use of hormonal combined oral contraceptives (COCs) and its association to return of fertility remains controversial. The goal of this study is to investigate the association between exposure to POPs, both individually and as a mixture, and fecundability measured as time-to-pregnancy (TTP) according to pre-pregnancy use of COCs and age.

METHODS

Using the SELMA (Swedish Environmental Longitudinal Mother and Child, Allergy and Asthma) study, we have identified 818 pregnant women aged 18-43 years (mean 29 years) with data on how long they tried to get pregnant and what was their most recently used contraceptive method. These data were collected at enrollment to the study (median week 10 of pregnancy). Concentrations of 22 POPs and cotinine were analyzed in the blood samples collected at the same time as the questions on TTP and pre-pregnancy use of contraceptive. Analyses were done on the association between POPs exposure and TTP measured as continuous (months) and binary (infertile for those with TTP > 12 months). To study the chemicals individually, Cox regression and logistic regression were used to estimate fecundability ratios (FRs) and odds ratios (ORs), respectively. Weighted quantile sum (WQS) regression was used to investigate the chemicals as a mixture where chemicals of concern were identified above the 7.6% threshold of equal weights. To perform the subgroup analysis, we stratified the sample according to use of COCs as the most recent pre-pregnancy contraception method and age (< 29 years, and ≥ 29 years). The models were adjusted for parity, regularity of menses, maternal body mass index (BMI) and smoking status, and stratified as described above.

RESULTS

Prior to stratification, none of the POPs were associated with fecundability while increased exposure to HCB, PCB 74 and 118 had higher odds of infertility. Upon stratification, POP exposure was significantly associated with longer TTP in women aged ≥29 years who did not use COC. Specifically, PCBs 156, 180, 183, and 187 were associated with reduced fecundability while PCBs 99, 153, 156, 180, 183, and 187 had higher odds of infertility. As a mixture, we identified the chemicals of concern for a longer TTP include PCBs 118, 156, 183, and 187. Moreover, chemicals of concern identified with increased odds of infertility were PCB 74, 156, 183, 187, and transnonachlor.

CONCLUSION

Serum concentrations of selected POPs, both as individual chemicals and as a mixture, were significantly associated with lower fecundability and increased odds of infertility in women aged 29 years and above not using COC as their most recent pre-pregnancy contraceptive. Our findings suggest that pre-pregnancy use of oral contraceptive and age may modify the link between POPs and fecundability. The differences of specific chemicals in the individual analysis and as a mixture support the need to study combination effects of chemicals when evaluating reproductive outcomes.

Menstrual bleeding, cycle length, and follicular and luteal phase lengths in women without known subfertility: A pooled analysis of three cohorts

BACKGROUND

There is variability between women for days of menstrual bleeding, cycle lengths, follicular phase lengths, and luteal phase lengths, related to age and parity.

OBJECTIVE

To describe total cycle length; anovulatory cycles; follicular and luteal phase lengths; and days and intensity of menstrual and non-menstrual bleeding in women without known subfertility over the course of 1 year.

METHODS

581 women (3,324 cycles) with no known subfertility (18-40 years of age) were followed for up to 1 year. Women recorded vaginal bleeding and mucus discharge daily. We used the peak day of cervical mucus as the estimated day of ovulation and the last day of the follicular phase. We used generalised linear mixed models stratified by age and parity to describe menstrual cycle parameters.

RESULTS

The majority of women were <30 years of age (74.5%), non-Hispanic White (88.6%), and nulliparous (70.4%). The mean menses length was 6.2 (1.5) days, median 6; cycle length 30.3 (6.7) days, median 29; follicular phase length 18.5 (6.5) days, median 17; and luteal phase length 11.7 (2.8) days, median 12. Nulliparous women aged ≥30 years vs nulliparous women aged <30 had shorter cycles (29.2 days, 95% confidence interval (CI) 27.8, 30.7 vs 31.5 days, 95% CI 30.8, 32.2) and shorter follicular phases (17.6 days, 95% CI 16.2, 18.9 vs 19.6 days, 95% CI 18.9, 20.2). Among all women, within-woman differences between the longest and shortest menses length >3 days, total cycle length >7 days, follicular phase >7 days, and luteal phase >3 days were found in 11.6%, 43.0%, 41.7%, and 58.8% of women, respectively.

CONCLUSIONS

Our findings confirm variability between women of menstrual cycle parameters related to age and parity, and also highlight within-woman variability in the follicular and luteal phases.

Pre-conception 25-hydroxyvitamin D (25(OH)D) and fecundability

STUDY QUESTION

Is pre-conception 25(OH)D associated with the per cycle probability of conception, i.e fecundability, in a prospective cohort study?

SUMMARY ANSWER

There are suggestive associations of high 25(OH)D (at least 50 ng/ml) with increased fecundability and low 25(OH)D (<20 ng/ml) with reduced fecundability, but the estimates were imprecise.

WHAT IS KNOWN ALREADY

Vitamin D has been associated with reproductive function and fertility in animal studies, but few human studies exist.

STUDY DESIGN, SIZE, DURATION

This community-based prospective cohort study included 522 women attempting to become pregnant between 2010 and 2016. The women completed online daily and monthly diaries until a positive home pregnancy test was observed or 12 months had elapsed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study included women from central North Carolina who were aged 30-44 with no history of infertility, with no more than 3 months of attempt time at recruitment. Women recorded vaginal bleeding so that the ongoing number of attempt cycles could be counted and used to quantify a woman's pregnancy attempt time. Blood collected at the study entry was analysed for 25(OH)D using liquid chromatography tandem mass spectrometry. Associations with fecundability were estimated with a log-binomial discrete time-to-event model.

MAIN RESULTS AND THE ROLE OF CHANCE

Among 522 women, 257 conceived during the study. The mean age was 33 years and the mean 25(OH)D was 36 ng/ml. There was an estimated 10% higher fecundability with each 10 ng/ml increase in 25(OH)D (fecundability ratio (FR) 1.10, 95% CI: 0.96, 1.25). The suggestive dose-response association with the continuous measure of 25(OH)D was driven by women in the lowest and the highest categories of 25(OH)D. Compared to women with 25(OH)D of 30-40 ng/ml, women below 20 ng/ml had an estimated 45% reduction in fecundability (FR (CI): 0.55 (0.23, 1.32)), and women with at least 50 ng/ml had an estimated 35% increase in fecundability (FR (CI): 1.35 (0.95, 1.91)). Across these three categories (25(OH)D of <20 ng/ml, 30-40 ng/ml and > 50 ng/ml), the probability of taking longer than 6 months to conceive was, respectively, 51% (17%, 74%), 28% (17%, 39%) and 15% (10%, 37%).

LIMITATIONS, REASONS FOR CAUTION

While the distribution of 25(OH)D was wide, the number of observed cycles with high 25(OH)D (N = 107) or low 25(OH)D (N = 56) was small.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings are consistent with prior reports of reduced fertility in women with 25(OH)D concentrations below the clinically defined deficiency level (20 ng/ml). Further studies are needed to evaluate the possible reproductive benefits of considerably higher 25(OH)D concentration (>50 ng/ml).

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health (NIH) under award numbers R00HD079659 and R01HD067683 and supported in part by the Intramural Research Program of the National Institute of Environmental Health Sciences, under projects ES103086, ES049003 and ES044003. ClearBlue ovulation predictor kits were generously donated to AMZJ and AJW by Swiss Precision Diagnostics. Drs Wilcox and Jukic report non-financial support from Swiss Precision Diagnostics during the conduct of the study; Dr Jukic reports non-financial support from Theralogix, LLC, outside the submitted work. Otherwise there are no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Fecundability in relation to use of fertility awareness indicators in a North American preconception cohort study

OBJECTIVE

To quantify the frequency of use of selected fertility awareness indicators and to assess their influence on fecundability.

DESIGN

Web-based prospective cohort study.

SETTING

Not applicable.

PATIENT(S)

Female pregnancy planners, aged 21-45 years, attempting conception for ≤6 cycles at study entry.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

We ascertained time to pregnancy, in menstrual cycles, with bimonthly questionnaires. We estimated adjusted fecundability ratios (FRs) and confidence intervals (CIs) using proportional probabilities models, controlling for age, income, education, smoking, intercourse frequency, and other lifestyle and reproductive factors.

RESULT(S)

A total of 5,688 women were analyzed, with a mean age of 29.9 years and mean time trying of 2.1 cycles at baseline; 30% had ever been pregnant. At baseline, 75% were using one or more fertility indicators (counting days or charting menstrual cycles [71%], measuring basal body temperature [BBT, 21%], monitoring cervical fluid [39%], using urine LH tests [32%], or feeling for changes in position of the cervix [12%]). Women using any fertility indicator at baseline had higher subsequent fecundability (adjusted FR 1.25, 95% CI 1.16-1.35) than those not using any fertility indicators. For each individual indicator, adjusted FRs ranged from 1.28-1.36, where 1.00 would indicate no relation with fecundability. The adjusted FR for women using a combination of charting days, cervical fluid, and urine LH was 1.48 (95% CI 1.31-1.67) relative to women using no fertility indicators.

CONCLUSION(S)

In a North American preconception cohort study, use of fertility indicators indicating the fertile window was common, and was associated with greater fecundability.

Assisted reproductive technology treatment and risk of ovarian cancer—a nationwide population-based cohort study

STUDY QUESTION

Does hormone stimulation during assisted reproductive technology (ART) treatment increase the risk of ovarian cancer?

SUMMARY ANSWER

No increased risk of ovarian cancer was found among ART-treated women, with the exception of ART-treated women with endometriosis.

WHAT IS KNOWN ALREADY

Previous studies on the association between ovarian stimulation during ART and ovarian cancer have shown conflicting results. The risk of ovarian cancer varies according to the cause of infertility, and only a few studies on ART treatment and risk of ovarian cancer have had sufficient data to address this issue. Endometriosis has been linked to an increased risk of ovarian cancer.

STUDY DESIGN, SIZE, DURATION

Women undergoing ART treatment during 1994–2015 were registered in the Danish IVF register. Data were linked with data from the Danish Cancer Register and socio-demographic population registers using an individual person identification number assigned to people residing in Denmark.

PARTICIPANTS/MATERIALS, SETTING, METHODS

All women undergoing ART treatment were age-matched with a random sample of the female background population and followed for up to 22 years. After relevant exclusions, the population consisted of 58 472 ART-treated women and 625 330 untreated women, all with no previous malignancies. Ovarian cancer risk was assessed using multivariable cox regression analyses with adjustment for educational level, marital status, parity and treatment year. Results are shown as hazard ratios (HRs) with corresponding CIs.

MAIN RESULTS AND THE ROLE OF CHANCE

In total, 393 (0.06%) women were diagnosed with ovarian cancer during follow-up (mean 9.7 years). Women treated with ART had an increased risk of ovarian cancer (HR 1.20, 95% CI 1.10–1.31), which diminished over time. The increased risk was apparent among women with female factor infertility (HR 1.36, 95% CI 1.25–1.48), whereas no female factor infertility was associated with a lower risk (HR 0.87, 95% CI 0.76–1.00). The risk was increased among women with endometriosis (HR 3.78, 95% CI 2.45–5.84), whereas no increased risk was found among ART-treated women with polycystic ovary syndrome, other female causes of infertility and unexplained infertility.

LIMITATIONS, REASONS FOR CAUTION

The association between ART treatment and ovarian cancer is likely influenced by increased detection due to multiple ultrasound scans during ART treatment.

WIDER IMPLICATIONS OF THE FINDINGS

Undergoing ART treatment without the presence of endometriosis was not associated with an increased risk of ovarian cancer, which is reassuring. Whether ART treatment increases the risk of ovarian cancer among women with endometriosis needs further investigation.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by a PhD grant to D.V. from the Faculty of Health and Medical Sciences, University of Copenhagen, Denmark. Funding for establishing the Danish National ART-couple II cohort was achieved from Ebba Rosa Hansen Foundation. The funders had no influence on data collection, analyses or results presented. The authors have no conflicts of interest to declare.

Kontrazeptionsbeginn in der Pubertät – wann, wie, womit?

Während der Pubertät stellen sich Mädchen in der Praxis oft mit Fragen bezüglich und dem Wunsch nach einer Verhütung vor. Diese Beratung ist eine besondere Herausforderung, da gerade in der Adoleszenz die zuverlässige Kontrazeption zur Vermeidung ungewollter Schwangerschaften sehr wichtig ist und die Jugendlichen durch Nebenwirkungen der Kontrazeptiva nicht verunsichert werden sollten. Dennoch ist es aus medizinischer Sicht obligat, Kontraindikationen wie beispielsweise ein erhöhtes Thromboserisiko oder Wechselwirkungen mit einer bestehenden Medikation abzuklären, um dann gemeinsam mit der Jugendlichen ein geeignetes Kontrazeptivum auszuwählen. Neben der am häufigsten verwendeten Verhütungsmethode in der Adoleszenz – kombinierte Hormonpräparate, auch ggf. im Langzyklus – sollten die Mädchen umfassend über Barrieremethoden, insbesondere über den zusätzlichen Gebrauch von Kondomen zum Schutz vor Geschlechtskrankheiten, über Notfallkontrazeption und über lang wirksame kontrazeptive Maßnahmen informiert werden.

No. 329-Canadian Contraception Consensus Part 4 of 4 Chapter 9: Combined Hormonal Contraception

OBJECTIVE

To provide guidelines for health care providers on the use of contraceptive methods to prevent pregnancy and on the promotion of healthy sexuality.

OUTCOMES

Overall efficacy of cited contraceptive methods, assessing reduction in pregnancy rate, safety, and side effects; the effect of cited contraceptive methods on sexual health and general well-being; and the availability of cited contraceptive methods in Canada.

EVIDENCE

Medline and the Cochrane Database were searched for articles in English on subjects related to contraception, sexuality, and sexual health from January 1994 to December 2015 in order to update the Canadian Contraception Consensus published February-April 2004. Relevant Canadian government publications and position papers from appropriate health and family planning organizations were also reviewed.

VALUES

The quality of the evidence is rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. Recommendations for practice are ranked according to the method described in this report.

SUMMARY STATEMENTS

RECOMMENDATIONS.

Short- and long-term effect of contraceptive methods on fecundity

Objective: The aim of the study was to compare the effect of previously used contraceptive methods on women's short- and long-term fecundity. Use of hormonal contraception (HC) was compared with the use of a contraceptive mobile application (app). Methods: This real-life prospective observational study comprised 2874 women who were attempting to become pregnant using the Natural Cycles mobile app to monitor their fertility. The women registered to use the app between August 2014 and June 2016 with the intention of planning a pregnancy and had previously either used the same app to prevent pregnancy or had recently discontinued HC use. We calculated the average time to pregnancy (TTP) for all women who became pregnant during the study and performed Kaplan-Meier life-table analysis to examine the cumulative probabilities of pregnancy for all women in the study. Results: The average TTP was 2.3 (95% confidence interval [CI] 2.1, 2.4) and 3.7 (95% CI 3.4, 3.9) cycles for women who had previously used Natural Cycles and HC, respectively. The time to reach 30% pregnancy probability for women previously on HC was 1.6 (95% CI 1.5, 1.8) times longer than for women previously using Natural Cycles. There was no significant difference in the 13 cycle cumulated pregnancy probability between the two groups. Conclusion: The results show that fertility awareness-based methods of contraception increase short-term pregnancy rates relative to HC, but have no effect on long-term pregnancy rates.

Women's Contraceptive Perceptions, Beliefs, and Attitudes: An Integrative Review of Qualitative Research

INTRODUCTION

Unintended pregnancy rates will remain high until researchers explore the lived experience of women's relationships with contraception. This integrative review examines the extant qualitative literature on women's contraception to illuminate common themes in women's perspectives through the lens of the feminist poststructuralist framework.

METHODS

A literature review of PubMed and CINAHL databases was completed for English-language studies conducted in the United States from January 2008 through September 2018 that qualitatively examined women's perceptions, beliefs, and attitudes regarding contraception. Reports, dissertations, mixed-methods research, and literature reviews were excluded. The sample, methods, and findings of 19 studies were reviewed. Themes were identified using the 5 major tenets of the feminist poststructuralist framework: discourse, power, language, subjectivity, and agency.

RESULTS

Themes of power imbalance between partners and health care providers; societal and communal discourses on femininity and motherhood; distrust of hormonal contraception; the ability to enhance personal agency through contraceptive decision making; and a need for open, patient-focused communication arose from the 19 studies included in the review.

DISCUSSION

Using a feminist poststructuralist framework to examine women's contraceptive perceptions illuminates and magnifies the many ways in which contraceptive beliefs and use are dependent on gender roles and power dynamics. Gaps in knowledge specific to older women and exploration of women's subjectivity should be addressed. Clinicians should evaluate the power structures inherent to their practice while providing woman-focused, evidence-based contraceptive education.

Causal explanations for lack of pregnancy applying the common sense model of illness representation to the fertility context

OBJECTIVES

The current study explored causal explanations for lack of pregnancy and association with help-seeking behaviour. Differences based on gender and country Human Development Index were examined.

DESIGN

A mixed method design was used.

MAIN OUTCOME MEASURES

Data were drawn from the International Fertility Decision-Making Study, a cross-sectional study of 10,045 individuals (1690 men; 8355 women) from 79 countries. Respondents rated to what extent they believed their lack of pregnancy was due to something they or their partner had done/not done or other factors and described their reasons for making this rating.

RESULTS

Respondents were aged 18-50 (M = 31.83) years, partnered and had been trying to achieve a pregnancy/father a child for over six months (M = 2.8 years). Men and women primarily believed their lack of pregnancy was due to medical problems or chance/bad luck. Thematic analysis of textual responses from 29.7% of the sample found that respondents focused on their personal experience or a salient life event when describing the cause of their lack of pregnancy. Women expressed more regret and helplessness about causes than men. Significant country differences were observed.

CONCLUSIONS

Individuals may develop inaccurate causal explanations based on their personal experiences. Access to accurate information is necessary to facilitate timely help-seeking.

Perceptions of and barriers to family planning services in the poorest regions of Chiapas, Mexico: a qualitative study of men, women, and adolescents

Background

In the poorest regions of Chiapas, Mexico, 50.2% of women in need of contraceptives do not use any modern method. A qualitative study was needed to design effective and culturally appropriate interventions.

Methods

We used purposive maximum-variation sampling to select eight municipalities with a high proportion of residents in the poorest wealth quintile, including urban, rural, indigenous, and non-indigenous communities. We conducted 44 focus group discussions with 292 women, adolescent women, and men using semi-structured topic guides. We analyzed the data through recursive abstraction.

Results

There were intergenerational and cultural gaps in the acceptability of family planning, and in some communities family planning use was greatly limited by gender roles and religious objections to contraception. Men strongly influenced family planning choices in many households, but were largely unreached by outreach and education programs due to their work hours. Respondents were aware of many modern methods but often lacked deeper knowledge and held misconceptions about long-term fertility risks posed by some hormonal methods. Acute physical side effects also dissuaded use. The implant was a new and highly acceptable method due to ease of use, low upkeep, and minimal side effects; however, it was perceived as subject to stock-outs. Adolescent women reported being refused services at health facilities and requested more reproductive health information from their parents and schools. Mass and social media are growing sources of reproductive health information.

Conclusions

Our study identifies a number of barriers to family planning that have yet to be adequately addressed by existing programs in Chiapas’ poorest regions, and calls for reinvigorated efforts to provide effective, acceptable, and culturally appropriate interventions for these communities.

Electronic supplementary material

The online version of this article (10.1186/s12978-017-0392-4) contains supplementary material, which is available to authorized users.

Economic Evaluations of Thrombophilia Screening Prior to Prescribing Combined Oral Contraceptives: A Systematic and Critical Review

BACKGROUND

Combined oral contraceptives (COCs) increase the risk of venous thromboembolism (VTE), particularly among women with inherited clotting disorders. The World Health Organization classifies combined hormonal contraception as an "unacceptable health risk" for women with thrombogenic mutations but advises against universal thrombophilia screening before prescribing COCs given the low prevalence of thrombophilia and high screening costs.

OBJECTIVE

Through the lens of lifetime costs and benefits, this paper systematically and critically reviews all published economic evaluations of thrombophilia screening prior to prescribing COCs.

METHODS

We searched relevant databases for economic evaluations of thrombophilia screening before prescribing COCs. After extracting the key study characteristics and economic variables, we evaluated each article using the Quality of Health Economic Studies (QHES) and the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) instruments.

RESULTS

Seven economic evaluations of thrombophilia screening before prescribing COCs met our inclusion criteria. Only the two economic evaluations focusing exclusively on selective screening exceeded the 75-point threshold for high-quality economic studies based on the QHES instrument, whereas only one of these exceeded the 85% CHEERS threshold. Only three of the seven economic evaluations performed sensitivity analysis on key parameters. Most studies underestimated the benefits of thrombophilia screening by comparing one-time costs of genetic screening against benefits per person-year, thus implicitly assuming a 1-year duration of COC use, neglecting the long-term implications of VTE and/or neglecting the lifetime benefits of awareness of inherited thrombophilia.

CONCLUSION

Our review highlights the lack of methodologically rigorous economic evaluations of universal thrombophilia screening before prescribing COCs.

Anti-Müllerian hormone levels and fecundability in women with a natural conception

OBJECTIVES

To investigate the association between anti-Müllerian hormone (AMH), a well-established marker of the ovarian reserve, and time-to-pregnancy (TTP) in natural conceptions, and to assess changes in serum-AMH in early pregnancy.

STUDY DESIGN

A cross sectional study comprising 279 women aged 21-42 years with a natural conception recruited during 2012-2014. AMH was measured in gestational week 10-19. AMH z-scores (z-AMH) adjusted for gestational week at blood sampling were categorised in the 1st, 2nd-4th (reference), and 5th quintile. Data were analysed by discrete-time survival-analysis and results presented as odds ratios (OR), 95% confidence interval (CI); OR <1 indicating a longer TTP and OR >1 indicating a shorter TTP.

RESULTS

The median AMH-level was 23.0 (range:<3.0;144.0)pmol/l, and serum-AMH decreased by 7.5% (95% CI:-12.0%;-2.8%) per gestational week. Mean±SD female age was 30.9±3.6years. The median TTP was 2 (range: 1-32) months. After adjustment for possible confounders including total sperm count, TTP was unrelated to female age (aOR:1.0, 95% CI:0.9;1.0) and continuous z-AMH (aOR:0.8, 95% CI:0.7;1.0), but women in the low z-AMH group had a shorter TTP than the reference group (aOR:1.7, 95% CI:1.1;2.7). TTP was prolonged in preconception oral contraceptive (OC) users (aOR:0.7, 95% CI:0.5;1.0, p=0.04). Compared with women having used OC <2 years, TTP was significantly longer in women having used OC for 2-12 years (aOR:0.5, 95% CI:0.2;1.0, p=0.048) and >12 years (aOR:0.4, 95% CI:0.2;0.9, p=0.022) after age-adjustment.

CONCLUSIONS

TTP was unrelated with z-AMH when modelled as a continuous covariate. Unexpectedly, TTP was shorter in the low z-AMH group. Natural conception was observed in women with a wide range of AMH-levels including women with undetectable serum-AMH. A continuous decrease in serum-AMH was observed during first and second trimester. Preconception OC-use was identified as an independent predictor of a prolonged TTP, and the duration of OC-use appeared to influence the delay in conception. Although this is presently one of the largest studies investigating the association between AMH and fecundability in fertile women, the study has some limitation including a relatively low participation rate and a risk of selection bias in addition to AMH assessment in pregnancy and a retrospective collection of TTP and OC-use associated with a risk of recall bias. These limitations may explain the unexpected finding of a shorter TTP in the low z-AMH group.

Fertility Awareness Counseling for Adolescent Girls; Guiding Conception: The Right Time, Right Weight, and Right Way

STUDY OBJECTIVE

To provide a detailed summary of fertility awareness counseling pearls for healthy teens and those with fertility-relevant comorbidities, and to assist providers in offering such counseling to adolescents and young adult women. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: Comprehensive literature review of English-language studies relating to fertility in pediatric and adolescent female patients (ages 13-21 years), and evidence-based dialogue guide.

RESULTS

The literature indicates that although adolescents are interested in discussing sexuality and reproduction, this is commonly overlooked during the standard office medical visit. As a result, adolescents often turn to less reliable sources and hold a variety of reproductive misconceptions and a sense of lack of control over future fertility. We found no studies that examined the routine provision of fertility awareness counseling with healthy adolescents. There are a multitude of specific gynecologic and medical conditions that have ramifications for fertility. We detail these comprehensively, and provide a dialogue guide to assist with fertility awareness counseling for the female adolescent, containing specific information and indications for referral.

CONCLUSION

Providers caring for adolescent girls have the opportunity to enhance fertility awareness as part of a larger reproductive health conversation that adolescents desire, and from which they might benefit. Identifying potential future fertility issues, understanding age-related fertility decline, and aiding in health optimization before future conception might empower the adolescent to make informed reproductive decisions. We provide an algorithm to use with adolescents to discuss the "right time, right weight, right way" to pursue childbearing.

The influence of age at menarche, menstrual cycle length and bleeding duration on time to pregnancy: a large prospective cohort study among rural Chinese women

OBJECTIVE

To investigate the relations among age at menarche (AAM), menstrual cycle length, menstrual bleeding duration and time to pregnancy in a large cohort of rural Chinese women.

DESIGN

A prospective cohort study.

SETTING

Local family-planning service agencies and maternal/child care service centres.

POPULATION

A total of 391 320 rural women of reproductive age who participated in the National Free Pre-pregnancy Checkups and were planning to conceive were enrolled.

METHODS

Menstrual characteristics were collected via face-to-face interviews. The Cox proportional hazards model were used to estimate the fecundability ratios (FRs) and 95% confidence intervals for each measure relative to its reference category.

MAIN OUTCOME MEASURES

Time to pregnancy.

RESULTS

Women with an AAM later than 14 years of age were less likely become pregnant compared with women with AAM at 13-14 years of age (FR 0.93, 95% CI 0.92-0.94). Those with menstrual cycle lengths >29 days were less likely to come pregnant (FR 0.91, 95% CI 0.90-0.92) compared with the reference cycle length of 27-29 days. Women with bleeding durations of <4 (FR 0.88; 95% CI 0.86-0.91) or >5 days (FR 0.91; 95% CI 0.90-0.91) showed lower FRs compared with those reporting 4-5 days of bleeding. The associations were independent of maternal age, ethnicity, education level, occupation, tobacco use, alcohol use and body mass index.

CONCLUSION

A later onset of menarche, longer menstrual cycle length, both shorter (<4 days) and longer (>5 days) bleeding duration were associated with a lower FR and longer time to pregnancy in rural Chinese women.

TWEETABLE ABSTRACT

A later menarche, longer cycle, shorter or longer bleeding duration were associated with lower fecundity.

Fertility and combined oral contraceptives - unintended pregnancies and planned pregnancies following oral contraceptive use - results from the INAS-SCORE study

OBJECTIVES

To estimate the real-use contraceptive effectiveness of the combined oral contraceptive containing dienogest and estradiol valerate (DNG/EV) and whether DNG/EV compared to other combined oral contraceptives (oCOC) has a negative effect on return to fertility.

METHODS

Transatlantic, prospective, non-interventional cohort study conducted in the USA and seven European countries with two main exposure groups and one exposure subgroup: new users of DNG/EV and other COC (oCOC), particularly levonorgestrel-containing COCs (LNG). In a planned secondary analysis, pregnancy outcomes were investigated including contraceptive effectiveness and pregnancy following contraceptive cessation. The influence of age, parity and OC-type were assessed.

RESULTS

50,203 COC users were followed for 105,761 woman-years (WY). There were 677 unintended pregnancies reported: 451 in the USA and 226 in Europe. The contraceptive failure rate in Europe was 0.5 events/100 WY (95% CI: 0.4-0.5) and in the USA 1.9 events/100 WY (95% CI: 1.7-2.1). Differences in compliance (1.3 pregnancies/100 WY) accounted for 90% of the geographical difference seen between Europe and the USA. DNG/EV showed lower contraceptive failure rates compared to the comparators; 0.9% DNG/EV, 2.1% oCOC and 2.8% LNG after 4 years. Overall, 1167 (2.3%) of women stopped contraceptive use with the intention of becoming pregnant with 89% conceiving within 2 years. No significant differences were seen between groups after adjusting for age.

CONCLUSION/DISCUSSION

DNG/EV is associated with similar contraceptive effectiveness in typical-use settings when compared to oCOC and LNG. There was no difference observed between cohorts in fertility following OC use.

Maternal Recall Error in Retrospectively Reported Time-to-Pregnancy: an Assessment and Bias Analysis

BACKGROUND

Epidemiologic studies of fecundability often use retrospectively measured time-to-pregnancy (TTP), thereby introducing potential for recall error. Little is known about how recall error affects the bias and precision of the fecundability odds ratio (FOR) in such studies.

METHODS

Using data from the Danish Snart-Gravid Study (2007-12), we quantified error for TTP recalled in the first trimester of pregnancy relative to prospectively measured TTP among 421 women who enrolled at the start of their pregnancy attempt and became pregnant within 12 months. We defined recall error as retrospectively measured TTP minus prospectively measured TTP. Using linear regression, we assessed mean differences in recall error by maternal characteristics. We evaluated the resulting bias in the FOR and 95% confidence interval (CI) using simulation analyses that compared corrected and uncorrected retrospectively measured TTP values.

RESULTS

Recall error (mean = -0.11 months, 95% CI -0.25, 0.04) was not appreciably associated with maternal age, gravidity, or recent oral contraceptive use. Women with TTP > 2 months were more likely to underestimate their TTP than women with TTP ≤ 2 months (unadjusted mean difference in error: -0.40 months, 95% CI -0.71, -0.09). FORs of recent oral contraceptive use calculated from prospectively measured, retrospectively measured, and corrected TTPs were 0.82 (95% CI 0.67, 0.99), 0.74 (95% CI 0.61, 0.90), and 0.77 (95% CI 0.62, 0.96), respectively.

CONCLUSIONS

Recall error was small on average among pregnancy planners who became pregnant within 12 months. Recall error biased the FOR of recent oral contraceptive use away from the null by 10%. Quantitative bias analysis of the FOR can help researchers quantify the bias from recall error.

History of oral contraceptive use and risk of spontaneous abortion

PURPOSE

To examine the association between pregravid oral contraceptive (OC) use and spontaneous abortion (SAB).

METHODS

In an Internet-based preconception cohort study of 4862 Danish pregnancy planners, we used Cox proportional hazards models to estimate adjusted hazard ratios and 95% confidence intervals (CIs) for the association between OC use and SAB. We controlled for maternal age, physical activity, parity, education, alcohol and caffeine consumption, body mass index, and smoking.

RESULTS

Compared with women who discontinued OCs >1 year before conception, HRs were 0.95 (95% confidence interval (CI) = 0.77-1.17), 0.99 (95% CI = 0.82-1.19), and 0.80 (95% CI = 0.60-1.06) for women who discontinued OCs 7-12, 2-6, and 0-1 months before conception, respectively. Compared with less than 4 years of OC use, HRs for 4-7, 8-11, and 12 years or more of OC use were 1.05 (95% CI = 0.80-1.37), 0.92 (95% CI = 0.71-1.19), and 0.88 (95% CI = 0.65-1.19), respectively. Dose of estrogen and generation of progestin were not materially associated with SAB risk.

CONCLUSIONS

We found no evidence that pregravid OC use is associated with an increase in SAB. Use within 1 month of conception was associated with a slightly lower risk of SAB, but this may be due to increased reproductive fitness in women who conceive quickly after discontinuation of OCs.

Pre-gravid oral contraceptive use in relation to birth weight: a prospective cohort study

Few studies have evaluated the association between pregravid oral contraceptive (OC) use and birth weight, and findings have been conflicting. We conducted a prospective cohort study of 5921 pregnancy planners in Denmark to evaluate recency, duration, and type of OC used before conception in relation to infant birth weight. Participants completed online questionnaires and reported detailed information on contraceptive history and covariates at baseline. Participants completed bimonthly follow-up questionnaires to update their pregnancy status for up to 12 months or until conception occurred. Birth weight data were ascertained from the Danish Medical Birth Registry for 4046 live births delivered by study participants between 2008 and 2010. We used multivariable linear and log-binomial regression analyses to control for confounding. Mean birth weight was higher among women who had used OCs within 0-1 months (mean difference = 97 g, CI 26, 168) or 2-6 months (mean difference = 40 g, CI -5, 85) before conception, compared with more than 12 months before conception. Mean birth weight was lower among women who had used OCs for long durations (mean difference comparing ≥12 with <4 years of OC use = -85 g, CI -158, -11). Our findings indicate that pregravid OC use within 6 months of conception may be associated with a small increase in birth weight, but that long duration of use may have the opposite effect. Results were stronger among male infants, among 2nd and 4th generation OC users, and among users of OCs with a higher estrogen dose.

Volitional determinants and age-related decline in fecundability: a general population prospective cohort study in Denmark

OBJECTIVE

To quantify the natural decline in fecundability by age and assess the effect of selected volitional factors.

DESIGN

Prospective cohort study of women attempting conception.

SETTING

Not applicable.

PARTICIPANT(S)

A total of 2,820 women without infertility, trying to conceive for less than 3 cycles at study entry.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Fecundability.

RESULT(S)

Age had little effect on fecundability except for women 35-40 years, for whom it was 0.77 relative to women aged 20-24 years. Male age showed a similar but smaller decrease, declining to 0.95 for men aged 35-39 years. The effect of age differed for parous and nulliparous women, with the latter experiencing much stronger age-related declines relative to fecundability at age 20 years. Frequency of intercourse, use of nonhormonal birth control as the last method, and timing of intercourse, each had small effects on fecundability. Women who were in the high-fecundability categories for all three of these volitional factors had an estimated probability of conceiving of 88% (95% confidence interval 83%-93%). Unlike age, these factors represent individual choices that together can offset some of the age-related decline in fecundability.

CONCLUSION(S)

Fecundability peaks around age 30 years, slightly earlier for nulliparous than for parous women, and then declines. The decline with age is more modest for men. Couples will experience a compounded effect of their separate age-related declines. At age 40 years, a couple's fecundability would be approximately half of what it was at age 30 years, but some of this decline can be counteracted by volitional factors affecting conception.