Infertility is a worldwide public health agenda affecting the personal, social, and economic life of an individual and the family as a whole. The difference in terms of definition, diagnostic cut points, study design, and source population make performing a meta-analysis on infertility difficult. The prevalence, classification, and causes of infertility are reported in population-based studies, demographic and health survey report or institution-based studies. Each method has its own advantages and disadvantages. The present meta-analysis used both population and institution-based studies which analyzed the proportion of primary and secondary infertility from the total infertility and report the prevalence of its causes. It analyzed the proportion of primary and secondary infertility and summarize the etiology of infertility.
In this meta-analysis, the included studies have reported a heterogeneous proportion of primary and secondary infertility. This difference in the proportion of infertility was depended on the reported causes of infertility. For instance, in study areas where sexually transmitted infections (STI) and infection following the first pregnancy or abortion are common, the proportion of secondary infertility was higher [29, 32, 33]. Whereas in areas where the management of the above conditions is relatively good, primary infertility outnumbers secondary infertility [18, 27, 34] (Table 1). However, the overall pooled proportion of primary and secondary infertility at the level of Africa was almost similar. This finding is in difference from a meta-analysis result in Iran, which reported the highest (78.4%) proportion of primary infertility. This difference may be related to the causes of infertility. Because, in developing countries, STI, abortion, puerperal sepsis, and pelvic inflammatory diseases are common. Such conditions are reported to be a risk factor for secondary infertility and probably be the causes for the higher proportion of secondary infertility [5, 29,30,31].
In the subgroup analysis, primary infertility was more common in North Africa (70.56%) while secondary infertility was highest in East Africa (69.63%). This finding is also supported by the World health organization (WHO) which reported more prevalent secondary infertility in Sub-Saharan countries [3]. This regional variation may be due to the difference in the etiologic factors. The studies conducted in East Africa reported common risk factors of infertility as; STI, history of abortion and complication during labor, inadequate health service, misuse of antibiotics and antimicrobial resistance [4, 24, 25]. The other subgroup analysis performed by the year of studies showed that the older studies reported a higher pooled proportion of secondary infertility, while recent studies reported a higher pooled proportion of primary infertility. Since older studies might have been conducted when there were poor health care coverage and a high prevalence of infectious causes of infertility, the proportion of secondary infertility is expectedly higher [3, 4].
With regard to the etiologic sources of infertility, female-related causes account for about 54% of the total infertility. This result is in agreement with a meta-analysis report of Agarwal et al. [37], and Eldib and Tashani [38]. Both meta-analyses reported the causes for 50% of infertility were due to female-related reasons, suggesting for priority should be given for the management of risk factors of female origin. Appropriate management of the causes of infertility, since many of them are infections of the reproductive tract or abortion following the first pregnancy, can greatly reduce the prevalence of infertility [30, 31]. However, the burden of all infertility should not be given for women, since 22% of the infertility causes are originated from the male.
In the current meta-analysis, the commonest reported causes of male infertility, oligospermia, and asthenozoospermia are related to the quality of sperm cells. As a result, providing infertile male with treatment that improves sperm quality appear to be important. A meta-analysis on randomized control trial studies reported enhanced sperm quality with supplementation of selenium and coenzyme Q10 [39].
The commonest causes of female infertility were pelvic inflammatory diseases, tubal factors, abortion, and ovulatory dysfunction. Similarly, a meta-analysis by Direkvand-Moghadam et al. reported these factors as causes of female infertility [40]. This indicates that the management of infections affecting the reproductive organs and abortion requires attention.
Overall, infertility is not only a personal issue rather a matter of generation. Therefore, health policymakers and the governments should focus on the provision and advancement of infertility clinics and prevention and management of reproductive tract infection and abortion. Unexplained causes of infertility were also reported, this signals to advance our diagnostic modalities. Some studies were conducted based on institutional diagnostic criteria which made the meta-analysis difficult. Therefore, it is recommended that researches should be conducted following the accepted definition of infertility and diagnostic cut-off points for the assessment of sperm quality. Infertility perplexes the life of especially women, this could be at least vanquished via psychological support.
In conclusion, the current meta-analysis identified an approximately equal proportion of primary and secondary infertility. North Africa and East Africa had more primary and secondary infertility respectively. Older and recent studies respectively reported a higher pooled proportion of secondary and primary infertility. Female related causes were responsible for more than half of infertility. Oligospermia, varicocele, and asthenozoospermia were the commonest reported causes of male infertility. Female infertility was commonly caused by tubal factors, abortion, pelvic inflammatory diseases, and ovulatory dysfunction. The currently available data appears to be not of good quality. This is a call for performing an informative and representative investigation at the level of Africa. On the other hand, interpretation and utilization of these findings should consider the presence of substantial heterogeneity between the included studies.
The current study provides valuable continental data on infertility and its causes, which is useful for regional health policymakers, although has limitations. One of such limitation is it only includes articles in the English language. Since there are many French speaking countries in Africa, it may miss important articles. In addition, some of the articles have a small sample size that may question their representativeness.
Not applicable.