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.

Women's reproductive span: a systematic scoping review.

STUDY QUESTION: What is the scope of literature regarding women's reproductive span in terms of definitions, trends and determinants? SUMMARY ANSWER: The scoping review found a wide variation in definitions, trends and determinants of biological, social and effective women's reproductive span. WHAT IS KNOWN ALREADY: A woman's reproductive span refers to her childbearing years. Its span influences a woman's reproductive decisions. STUDY DESIGN SIZE DURATION: A systematic scoping review was conducted. We searched MEDLINE, PubMed, JSTOR, CINAHL, Web of Science and Scopus electronic databases from inception to January 2021 without imposing language or date restrictions. We searched unpublished sources including the Global Burden of Disease, Demographic and Health Surveys, and National Health and Nutrition Examination Surveys. The list of relevant references was searched by hand. Sixty-seven reports on women's reproductive span were included in this review. PARTICIPANTS/MATERIALS SETTING METHODS: This scoping systematic review followed an established framework. The reporting of this scoping review followed the reporting requirements provided in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, Extension for Scoping Reviews. Identified records were independently screened and data were extracted. We performed conceptual synthesis by grouping the studies by available concepts of reproductive span and then summarized definitions, measures used, temporal trends, determinants, and broad findings of implications on population demographics and assisted reproduction. Structured tabulation and graphical synthesis were used to show patterns in the data and convey detailed information efficiently, along with a narrative commentary. MAIN RESULTS AND THE ROLE OF CHANCE: A total of 67 relevant reports on women's reproductive span were published between 1980 and 2020 from 74 countries. Most reports (42/67) were cross-sectional in design. Literature on reproductive span was conceptually grouped as biological (the interval between age at menarche and age at menopause), effective (when a woman is both fertile and engaging in sexual activity) and social (period of exposure to sexual activity). We summarized the working definitions, trends and determinants of each concept. Few articles addressed implications on demographics and assisted reproduction. LIMITATIONS REASONS FOR CAUTION: A formal assessment of methodological quality of the included studies was not performed because the aim of this review was to provide an overview of the existing evidence base regardless of quality. WIDER IMPLICATIONS OF THE FINDINGS: The review produced a comprehensive set of possible definitions of women's reproductive span, trends, and potential determinants. Further advancement of these findings will involve collaboration with relevant stakeholders to rate the importance of each definition in relation to demography and fertility care, outline a set of core definitions, identify implications for policy, practice or research and define future research opportunities to explore linkages between reproductive spans, their determinants, and the need for assisted reproduction. STUDY FUNDING/COMPETING INTERESTS: This work received funding from the UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), a cosponsored programme executed by the World Health Organization (WHO). The authors had no competing interests. STUDY REGISTRATION NUMBER: N/A.

Enrolment and retention of people who inject drugs in the Needle & Syringe Exchange Programme in Malaysia.

Setting: Needle and Syringe Exchange Programme (NSEP) implemented by non-governmental organisations in Malaysia. Objectives: To determine enrolment, characteristics and retention in the NSEP of people who inject drugs (PWID) between 2013 and 2015. Design: Retrospective cohort study. Results: There were 20 946 PWID, with a mean age of 38 years. The majority were male (98%) and of Malay ethnicity (92%). Follow-up data were available for 20 761 PWID. Annual retention of newly enrolled PWID for each year was respectively 85%, 87% and 78% for 2013, 2014 and 2015, although annual enrolment over these years declined from 10 724 to 6288 to 3749. Total person-years (py) of follow-up were 27 806, with loss to follow-up of 40 per 100 py. Cumulative probability of retention in NSEP was 66% at 12 months, 45% at 24 months and 26% at 36 months. Significantly higher loss to follow-up rates were observed in those aged 15-24 years or ⩾50 years, females, transgender people and non-Malay ethnic groups. Conclusion: Annual retention of new PWID on NSEP was impressive, although enrolment declined over the 3 years of the study and cumulative loss to follow-up was high. A better understanding of these programmatic outcomes is required.

Contexte: Programme d'échange d'aiguilles et de seringues (NSEP) mis en œuvre par des organisations non-gouvernementales en Malaysie.Objectif: Déterminer l'enrôlement, les caractéristiques et la rétention dans le NSEP des personnes qui s'injectent des drogues (PWID) entre 2013 et 2015.Schéma: Etude rétrospective de cohorte.Résultats: Il y a eu 20 946 PWID, dont l'âge moyen a été de 38 ans. La majorité a été de sexe masculin (98%) et d'ethnie malaise (92%). Les données de suivi ont été disponibles pour 20 761 PWID. Le taux de rétention annuel des PWID nouvellement enrôlés a été de 85%, 87% et 78% pour 2013, 2014 et 2015, respectivement, bien que l'enrôlement annuel ait décliné de 10 724 à 6288, puis à 3749. Le suivi total en personnes-années (py) a été de 27 806, avec des pertes de vue de 40 pour 100 py. La probabilité cumulative de rétention dans le NSEP a été de 66% à 12 mois, de 45% à 24 mois et de 26% à 36 mois. Des taux de perdus de vue significativement plus élevés sont survenus chez les patients âgés de 15 à 24 ans ou ⩾50 ans, de sexe féminin, transgenre et d'un groupe ethnique autre que malais.Conclusion: La rétention annuelle des nouveaux PWID dans la NSEP a été impressionnante, bien que l'enrôlement ait décliné sur les 3 ans de l'étude et que les pertes de vue cumulées aient été élevées. Une meilleure compréhension de ces résultats du programme est requise.

Marco de referencia: El programa nacional de intercambio de agujas y jeringuillas introducido (NSEP) por organizaciones no gubernamentales en Malasia.Objetivos: Describir la inscripción, la permanencia y las características de las personas consumidoras de drogas inyectables (PWID) que participaron en el programa NSEP entre el 2013 y el 2015.Método: Fue este une estudio retrospectivo de cohortes.Resultados: Se inscribieron en el programa 20 946 PWID, cuya edad promedio fue 38 años. La mayoría era de sexo masculino (98%) y de etnia malaya (92%). Se practicó el seguimiento de 20 761 personas. La tasa anual de permanencia en el programa de los recién inscritos fue 85% en el 2013, 87% en el 2014 y 78% en el 2015, pero la tasa inscripción anual disminuyó de 10 724 a 6288 y 3749 personas, respectivamente. Se logró un seguimiento total de 27 806 años-persona (py), con una pérdida durante el seguimiento de 40 por 100 py. La probabilidad acumulada de permanencia en el programa fue 66% a los 12 meses, 45% a los 24 meses y 26% a los 36 meses. Las pérdidas durante el seguimiento fueron significativamente mayores en el grupo de 15 a 24 años de edad o a partir de los 50 años, en las mujeres, las personas transgénero y los grupos étnicos diferentes al malayo.Conclusión: La tasa anual de retención de las PWID recién inscritas en el programa NSEP fue sorprendente, pese a que las inscripciones disminuyeron durante los 3 años y las pérdidas acumuladas durante el seguimiento fueron altas. Es necesario ampliar la comprensión de estos resultados programáticos.

Optimizing the configuration of cement keyholes for acetabular fixation in total hip replacement using Taguchi experimental design.

Cement fixation of the acetabular component is increasingly recognized as a common site of loosening when hip replacements fail. Cement keyholes drilled into the acetabulum have been recommended to improve this fixation but little is known of the optimum positions or sizes of these holes. This study investigates the diameter, depth and number of keyholes to be drilled to maximize the failure torque in a model system. A Taguchi experimental design was used to identify the most significant factors and to predict the best configuration of keyholes within the constraints of the experimental test rig. One hole at each of the pubic, iliac and ischial sites, of 12 mm diameter and 6 mm depth, was found to be the optimum configuration. The failure torque was most strongly dependent on the hole diameter in the pubic region, decreased with increasing hole depth and was not sensitive to the number of holes.