Infertility is a complex and multifaceted reproductive health issue that warrants a thorough exploration of its epidemiology and sociodemographic predictors. Our study aimed to provide insights into the incidence, prevalence, and sociodemographic predictors of infertility among women attending the Gynaecologic Clinics of the University of Ilorin Teaching Hospital over a 5-year period.
The mean age of the infertile women studied was 32.8 ± 6 years and more than half of them were ≥ 30 years old. These findings are higher but comparable to that reported by Panti et al in their study among infertile women in Sokoto, North-west Nigeria, where they reported mean age of 28.9 ± 6.5 years, and that higher percentage of their participants were < 30 years of age.6 Age is one of the most important determinants of fertility, as increasing age during the reproductive years tends to decrease fertility in both women and men due to aging of the reproductive organs. Considering the level of education of the participants, more than half of them had at least tertiary education which reflects the increasing level of female education in Ilorin, North-central Nigeria. It might also be argued that the percentage of women with tertiary level of education in infertile women was greater than that of the general population put at 40.2% in 2011.12
Furthermore, it is not surprising that most (80.5%) of the participants were working actively during the study period given the mean age of the participants. This might also be linked to the development of infertility in them as shown by Okpala et al, in Lagos Nigeria. They reported that civil servants were more likely to develop infertility due to work demands, and that increasing number of work years and daily hours of work negatively affect fertility.13 They also reported that the number of children ever born was significantly higher in unemployed housewives compared to actively working civil servants.13
Family history of infertility risk assessment is an important tool in counselling the couples about their genetic risks prior to pregnancy.14 For some couples it might also provide information about the causes of their infertility.14 For this study, only 1.3% of the participants had a documented family history of infertility in their first-degree relatives which align with the fact that genetics have limited aetiological role in infertility.15 Only approximately 10 to 15 percent of infertility cases are reported to be due to a known inherited cause.15
Year on year comparison of the prevalence and incidence rates during the study period revealed that there was 52.1% increase in the prevalence of infertility from 6.9% in 2014 to 14.4% in 2018. Similarly, the incidence rates also increased by 59.4% from 2806/100,000 women in 2014 to 6918/100,000 women in 2018. The 5-year cumulative incidence (incidence proportion) and the 5-year overall prevalence of infertility in the study was 14.4%. This value is similar to prevalence of infertility reported in other Nigerian studies.6, 16, 17 It is also within the 5–23% prevalence of infertility range reported in Sub-Saharan Africa, and the 3.5–16.7% reported by Boivin et al, from review of 25 population surveys globally.18, 19
Our findings align with previous studies in Nigeria, indicating that about twice number of infertile women experienced secondary rather than primary infertility, emphasizing the need for targeted interventions and support for this specific subgroup.5, 6, 20 The 71.6% prevalence of secondary infertility and 28.4% of primary infertility recorded over the 5-year period of this study done in North-central Nigeria is exactly the same prevalence reported by Menuba et al, in their multi-centred prospective cross-sectional study in South-eastern Nigeira.20 The most commonly reported aetiological factor of secondary infertility in Nigerian women is chronic pelvic inflammatory disease which when comprehensively treated and managed would lead to reduction in the incidence of secondary infertility in the country.21, 22
Statistically significant sociodemographic factors found to have higher association with the development of secondary infertility in the participants in this study were higher age (≥ 30 years, P = 0.041), less than tertiary education status (P = 0.020) and being married in a polygamous marriage setting (P = 0.003). These findings are similar to those reported by Oguejiofor et al in Nnewi, South-eastern Nigeria.23 They reported in their 5-year retrospective study that most of their participants had secondary infertility, were older than 30 years, and had less than tertiary education.23 Further analysis in this study revealed that only being married in a polygamous setting remained significant determinant of secondary infertility in the study population. This could be explained by the affected women having regular sexual intercourse with men that have other wives which might increase the risk of pelvic inflammatory disease and tubal blockage in them. It might also be because more older women tend to marry into a polygamous marriage setting out of desperation to get a partner compared to younger women in the study population which might reduce their fertility. Egbe et al, in their paper on risk factors for tubal infertility reported that, young age, persons in monogamous marriages and users of barrier methods of contraception (condom) were less likely to have tubal infertility.24 Also, a large population survey in West Africa revealed that there was no significant difference in fertility rates between women in polygamous unions and those in monogamous households in almost all countries studied.25 This emphasizes that the predictability of polygamous marriage for secondary infertility does not include all cases of infertility.
Understanding the epidemiology and sociodemographic predictors of infertility is pivotal for designing targeted interventions and support systems for the affected women. The high prevalence of secondary infertility underscores the importance of investigating underlying causes and implementing preventive strategies. Moreover, addressing age-related factors and considering sociodemographic characteristics can enhance the effectiveness of reproductive health programs in the study population.
Despite the valuable data generated from this study, the study has some limitations, including that it is a single-centred hospital-based study, the fact that it is a retrospective study also meant that we were limited to only the documented information and available manual records. We suggest that future research should involve diverse populations and explore additional sociodemographic factors contributing to epidemiology of infertility in Nigeria.
In conclusion, our study contributes valuable data on the epidemiology and sociodemographic predictors of infertility among women attending the Gynaecology Clinics of the University of Ilorin Teaching Hospital. These findings we hope will provide a foundation for further research and the development of targeted interventions to address infertility in the local context.