Measuring infertility: searching for consensus

Comparing the occurrence rate of gestational hypertension during pregnancy with frozen embryo transfer and natural pregnancy

Introduction

Recent researches have indicated that pregnancies with frozen embryo transfer are associated with the increment of risk of maternal and neonatal complications, especially hypertension during pregnancy. The present study aimed to compare the occurrence rate of gestational hypertension in pregnancy with frozen embryo transfer and normal pregnancy.

Materials and Methods

This research, as a retrospective cross-sectional study, was performed on pregnant women with frozen embryo transfer (n = 97) and women with normal pregnancies (n = 164) referring to medical centers under the supervision of Ahvaz University of Medical Sciences in 2021. Women aged 18-35 were included in the study after week 20th of pregnancy. Maternal and neonatal outcomes including hypertensive disorders of pregnancy (including gestational hypertension and preeclampsia), preterm birth (before the week 37th), low birth weight (lower than 2500 g), neonatal asphyxia (Apgar score >7 in minute 5th), intrauterine growth restriction (IUGR) and bleeding in the first trimester of pregnancy were evaluated. The association between frozen embryo transfer and pregnancy outcomes was evaluated using multiple logistic regressions.

Results

The findings of this study indicated that pregnancy hypertension was observed in 23 people (23.7%) from the frozen embryo transfer group vs. 18 people (11.0%) from the normal pregnancy group (P = 0.006). Frozen embryo transfer pregnancy has a higher risk of gestational hypertension (OR = 2.521, 95% CI: 1.281-4.962; P = 0.007), preterm birth (OR = 2.264, 95% CI: 1.335-3.840; P = 0.002), and low birth weight (OR = 2.017, 95% CI: 1.178-3.455; P = 0.011). However, the incidence of birth asphyxia (P = 0.850), intrauterine growth restriction (P = 0.068), first-trimester bleeding (P = 0.809), and placenta accreta (P = 0.143) did not show a significant difference between two types of normal pregnancy and frozen embryo transfer pregnancy.

Conclusion

Frozen embryo transfer pregnancy was associated with a higher risk of maternal and neonatal complications, hypertension, preterm birth, and low birth weight compared to natural and spontaneous pregnancies.

Infertility prevalence and the methods of estimation from 1990 to 2021: a systematic review and meta-analysis

STUDY QUESTION

What is the contemporary prevalence of infertility in world populations and how do they differ by methodological and study characteristics?

SUMMARY ANSWER

Pooled estimates of lifetime and period prevalence of 12-month infertility were 17.5% and 12.6%, respectively, but this varied by study population and methodological approach.

WHAT IS KNOWN ALREADY

Infertility affects millions of individuals worldwide. Accurate measures of its magnitude are needed to effectively address and manage the condition. There are distinct challenges and variation in how infertility is defined and measured, limiting comparability of estimates across studies. Further research is needed to understand whether and how differences in methodological approaches and study characteristics account for heterogeneity in estimates.

STUDY DESIGN SIZE DURATION

We conducted a systematic review and meta-analysis. Six electronic databases, websites of relevant organizations, and conference proceedings were systematically searched. Searches were limited to those published between 1 January 1990 and 11 March 2021, with no language restrictions.

PARTICIPANTS/MATERIALS SETTING METHODS

Descriptive and random-effects meta-analysis models were used to examine range of estimates and generate estimates of pooled lifetime and period prevalence of 12-month infertility, respectively, among representative populations. Meta-regression using restricted maximum likelihood was applied to account for definitional and study characteristics and to obtain adjusted estimates. Risk of bias was assessed with a validated tool.

MAIN RESULTS AND THE ROLE OF CHANCE

The search yielded 12 241 unique records of which 133 studies met the criteria for the systematic review. There were 65 and 69 studies that provided data for lifetime and period prevalence of 12-month infertility, respectively. Five methodological approaches were identified: prospective time-to-pregnancy (TTP) design, current duration design, retrospective TTP design, self-reported infertility measure and constructed infertility measure. Ranges for lifetime (3.3-39.7%) and period estimates (1.6-34.0%) were similar and wide even after accounting for methodological and study characteristics. Pooled estimates of lifetime and period prevalence were 17.5% (95% CI: 15.0, 20.3, n = 37 studies, I ² = 99.5%) and 12.6% (95% CI: 10.7, 14.6, n = 43 studies, I ² = 99.8%), respectively, with some variation in magnitude by region and methodological approach, but with most CIs overlapping.

LIMITATIONS REASONS FOR CAUTION

Pooled estimates generated from meta-analysis were derived from 12-month infertility prevalence estimates that were heterogeneous across different domains, even after adjusting for definitional and study characteristics. The number of studies was small for certain strata from which pooled estimates were derived (e.g. there were only two studies for lifetime prevalence in Africa).

WIDER IMPLICATIONS OF THE FINDINGS

While findings show a high prevalence of infertility globally and regionally, it also reveals variation in measures to ascertain and compare infertility prevalence. More systematic and comprehensive collection of data using a consistent definition is needed to improve infertility prevalence estimates at global, regional and country-levels.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the World Health Organization. The authors have no conflicts of interest.

REGISTRATION NUMBER

PROSPERO CRD42020211704.

Self-reported fertility impairments and help-seeking strategies among young women in Malawi

This paper analyses wave 4 the Tsogolo la Thanzi survey of n = 1349 Malawian women aged 16–26 to explore the prevalence and predictors of self-reported fertility impairments (difficulties conceiving and/or difficulties carrying a pregnancy to term) and help-seeking strategies. Using descriptive statistics, logistic regression models, and graphic displays, the correlates of self-reporting an impairment and patterns of help-seeking strategies are examined. Nearly 13% (n = 117) of those who had ever tried to conceive reported experiencing a fertility impairment. Age was positively associated with reporting an impairment, while there was a negative association with education and with parity. Of women who reported an impairment, 85.5% sought help. Visiting a hospital or clinic was the most common response, followed closely by going to a traditional healer. Around one-quarter employed multiple help-seeking strategies, highlighting the need for various help-seeking behaviours to be viewed in tandem rather than in isolation.

Self-reported infertility, metabolic dysfunction, and cardiovascular events: a cross-sectional analysis among U.S. women

OBJECTIVE

To explore associations between infertility and metabolic syndrome, and cardiovascular events. Infertility is increasingly a public health issue, with emerging links to chronic disease. Existing literature on infertility focuses primarily on known causes, which likely excludes a substantial number of women for whom there is no known cause or formal diagnosis.

DESIGN/SETTING

We conducted a cross-sectional analysis examining the association between self-reported infertility (i.e., ever experiencing inability to conceive after 12 months of trying to become pregnant) and metabolic syndrome and cardiovascular events (i.e., congestive heart failure, coronary heart disease, heart attack, or stroke). Data were analyzed using multivariate logistic regression.

PATIENT(S)

A total of 744 U.S. women, 20-59 years of age, from the National Health and Nutrition Examination Survey (2013-2014), participated in the study. Among them, 15.7% reported ever experiencing infertility, 27.6% met the definition of metabolic syndrome, and 2.84% reported ever having a cardiovascular event.

INTERVENTION(S)

N/A.

MAIN OUTCOME MEASURE(S)

Metabolic syndrome and cardiovascular events.

RESULTS

Compared to women who had never experienced infertility, women who reported infertility had a 1.79 (95% confidence interval [CI] 1.04, 3.08) higher odds of reporting symptoms of metabolic syndrome and 1.83 (95% CI 1.15, 2.89) times higher odds of having experienced a cardiovascular event. Furthermore, women with self-reported infertility had a 71% higher odds of reporting a cardiovascular event after controlling for metabolic syndrome (95% CI 1.01, 3.00).

CONCLUSIONS

Our results suggest that among U.S. women, the experience of infertility at any point in a woman's reproductive window may be associated with later-life cardiovascular health.

Estimating infertility prevalence in low-to-middle-income countries: an application of a current duration approach to Demographic and Health Survey data

STUDY QUESTION

Can infertility prevalence be estimated using a current duration (CD) approach when applied to nationally representative Demographic and Health Survey (DHS) data collected routinely in low- or middle-income countries?

SUMMARY ANSWER

Our analysis suggests that a CD approach applied to DHS data from Nigeria provides infertility prevalence estimates comparable to other smaller studies in the same region.

WHAT IS KNOWN ALREADY

Despite associations with serious negative health, social and economic outcomes, infertility in developing countries is a marginalized issue in sexual and reproductive health. Obtaining reliable, nationally representative prevalence estimates is critical to address the issue, but methodological and resource challenges have impeded this goal.

STUDY DESIGN, SIZE, DURATION

This cross-sectional study was based on standard information available in the DHS core questionnaire and data sets, which are collected routinely among participating low-to-middle-income countries. Our research question was examined among women participating in the 2013 Nigeria DHS (n = 38 948). Among women eligible for the study, 98% were interviewed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We applied a CD approach (i.e. current length of time-at-risk of pregnancy) to estimate time-to-pregnancy (TTP) and 12-month infertility prevalence among women ‘at risk’ of pregnancy at the time of interview (n = 7063). Women who were 18–44 years old, married or cohabitating, sexually active within the past 4 weeks and not currently using contraception (and had not been sterilized) were included in the analysis. Estimates were based on parametric survival methods using bootstrap methods (500 bootstrap replicates) to obtain 95% CIs.

MAIN RESULTS AND THE ROLE OF CHANCE

The estimated median TTP among couples at risk of pregnancy was 5.1 months (95% CI: 4.2–6.3). The estimated percentage of infertile couples was 31.1% (95% CI: 27.9–34.7%)—consistent with other smaller studies from Nigeria. Primary infertility (17.4%, 95% CI: 12.9–23.8%) was substantially lower than secondary infertility (34.1%, 95% CI: 30.3–39.3%) in this population. Overall estimates for TTP >24 or >36 months dropped to 17.7% (95% CI: 15.7–20%) and 11.5% (95% CI: 10.2–13%), respectively. Subgroup analyses showed that estimates varied by age, coital frequency and fertility intentions, while being in a polygynous relationship showed minimal impact.

LIMITATIONS, REASONS FOR CAUTION

The CD approach may be limited by assumptions on when exposure to risk of pregnancy began and methodologic assumptions required for estimation, which may be less accurate for particular subgroups or populations. Unrecognized pregnancies may have also biased our findings; however, we attempted to address this in our exclusion criteria. Limiting to married/cohabiting couples may have excluded women who are no longer in a relationship after being blamed for infertility. Although probably rare in this setting, we lack information on couples undergoing infertility treatment. Like other TTP measurement approaches, pregnancies resulting from contraceptive failure are not included, which may bias estimates.

WIDER IMPLICATIONS OF THE FINDINGS

Nationally representative estimates of TTP and infertility based on a clinical definition of 12 months have been limited within developing countries. This approach represents a pragmatic advance in our ability to measure and monitor infertility in the developing world, with potentially far-reaching implications for policies and programs intended to address reproductive health.

STUDY FUNDING/COMPETING INTERESTS

There are no competing interests and no financial support was provided for this study. Financial support for Open Access publication was provided by the World Health Organization.