This study demonstrated that majority of women in fertile group were in the age category of 25-29 years and the previous study, conducted in Sri Lanka have shown the same result(9). The mean age of marriage of female in Sri Lanka is 23.4 years(17). But in this study it was a 25 and 26.5 years for fertile and sub-fertile women respectively. Differentiation according to ethnicity could not be observed between Tamil and Sinhala but percentage of Muslim women in sub-fertile group was comparatively low. Moreover it has been showed by one study that Muslims have high fertility than other ethnic group in Sri Lanka(18). Majority of women of fertile and sub-fertile groups are A/L qualified and percentage is equal for both groups (45%). There was no anyone with post graduate qualification in sub-fertile group and percentage of women with education qualification, upper than A/L was higher among fertile group. But some previous studies showed that level of education of women affect in three fertility outcomes, childlessness, timing of children, and number of children(19). In spite of that another study have stated that there is no association between level of education and knowledge on fertility(20).
Sub-fertile women had high usage of family planning, and oral contraceptives and condoms are the most common methods. But we did not observe the association between years of sub-fertility and family planning usage (Independent sample T test). The most probable reason of that was sub-fertility has a complex aetiology and time for sub-fertility is depend on lot of confounding factors. Although national Contraceptive Prevalence Rate (CPR) in Sri Lanka is 65%, it did not affect to the sub-fertility(21). Furthermore few studies have demonstrated that both condom usage and oral contraceptives can preserve fertility of women(22,23). The mean value of BMI of sub-fertile women was in the healthy range but it was 23.4 for fertile women as well as the percentage of obese women was high among fertile than sub-fertile (30% and 10.5%).But conversely previous studies have stated that overweight and obesity of women had poor reproductive outcomes(24,25). In this study, participants were measured only for general obesity not for the abdominal obesity, as well as certain study have mentioned that abdominal obesity have more adverse effect on fertility(26). Moreover one previous study have been stated the need for more intervention to reduce the BMI to increase the fertility of young women(27).
This study compared the moderate and vigorous physical activities of fertile and sub-fertile women and it demonstrated that sub-fertile women had higher MET of vigorous and moderate physical activities than fertile women. The most common vigorous physical activities were cycling, aerobics, construction works and involved day today activities in high intensities. This was supported by previous study and it had been concluded that increased frequency, duration, and intensity of physical activity were associated with increased sub-fertility(28). In spite of that most of women involved the moderate physical activities like, light weight lifting, aerobics, washing cloths and other day today activities. Further, we found that there was a 59% fertile woman live with extended family. Hence the domestic and day today activities are shared with family members and therefore opportunity to involve the physical activity is low in extended family. But One previous study stated that women who involved moderate physical activity has took relatively short duration to get pregnant than who did not involve(29). As well as another study concludes that moderate physical activities improve the fertility regardless the BMI(30). Walking is an important moderate physical activity because anybody can easily involve and considerable amount of calories can be burned. Therefore walking was analysed separately, and it had been found that MET of walking of sub-fertile women was higher than fertile women. The mean tank of total sitting time was not significantly different between two groups. But total sitting time was associated with the occupation of both groups. The occupations, way of transport, and hobbies of fertile women were more sedentary than sub-fertile. Moreover reading newspaper, and novels, entertains with music, watching television, and involving other screen based hobbies were the dominant sedentary activities of both groups. But fertile women spent more times for those activities than sub-fertile and house wives of both groups had more sedentary time than other professions. This finding is similar to some previous studies which was stated that sedentary hobbies are not associated with the fertility of the women(31,32).
To find the association between Second Hand Smoking (SHS) and sub-fertility, O.R was calculated (O.R=1.3). O.R 1.3 means that woman who expose to SHS has 1.3 times higher chance to be sub-fertile than woman who does not expose to SHS. The findings have been demonstrated by previous studies. One study concluded that if women are exposed to SHS from more than two years they have the problem with conserving and early menopause(33). The deleterious effects of smoking for the fertility of women are obvious and it has been proved with several epidemiological studies(34,35) Another study states that risk of SHS s similar to the active smoking and women and children are more vulnerable for SHS(36). But conversely another study showed that SHS is not appreciably associated with fertility of women(37).
Women in both groups in our study did not expose to tobacco smoke for a long period, as well as their frequency of exposure and duration was very low. Instead of that most of women exposed to SHS at their home environment and therefore they have opportunity to avoid the harmful exposure. Sleep is a critical component to health and well-being. Therefore number of sleeping hours was taken in to consideration in our study. But we identified there was a majority of sub-fertile women had not good restful sleep at night and one study has found that quality of sleep and duration of sleep is associated with the level of stress(38). As well as another two studies have stated that mental stress increase the risk of sub-fertility(39,40). This was reinforced by two previous studies and it has been stated that poor sleep cause to irregularities of menstrual cycle which cause to sub-fertility(41,42).
Hobbies were analysed to find the association for fertility of two groups because most of hobbies cause to reduce the stress and improve the fertility by regulating the healthy hormones. Some studies have showed that listening to music can reduce emotional distress and improve the fertility(43)(42). In this study odds ratio was calculated (O.R=0.6) to find the association between music and sub-fertility and the result indicated that entertainment with music is a protective factor to increase the fertility. Furthermore we found that going picnic and involving social works were high among fertile women than sub-fertile. These events help to detachment of day today busy work and it is great opportunity to get together with friends and family members. One study showed that tourism has the positive effect on life satisfaction and reduce the level of stress(44). Petting animal was not the hobby of majority of women in both groups and comparatively the percentage of fertile women was high. But some literature pointed out that petting animal, provide an unconditional source of affection, enhance self-esteem, and emotional stability, reduce the feeling of loneliness and isolation and help to people to socialize (45).
Religious practices help to cope-up the stressful life situations and therefore stress releasing religious practices were analysed with fertile and sub-fertile groups. But lot of practices are inherent to the particular religion and people are adhering to follow according their own religious beliefs. But one previous study showed that any religious practice can help to reduce the distress of sub-fertile women (46). Our study demonstrated that the percentage of Sub-fertile women, who involved the meditation, were higher than percentage of fertile women. Involving meditation help to be mindfulness and it pave the way to reduce the stress(47). Another study indicated that meditation help to reduce the stress due to fertility problems of women(40).
According to our study findings, religious practices, such as boodi puja, pirith chanting, and belief and superstition were very common to Buddhist women and those were analyzed only for Buddhists. It was found that sub-fertile women follow the belief and superstition rather than fertile women. A broad range of human behaviour is influenced by religion and religious practices which are imperative to affect the fertility of human being. Hence the women who expects to achieve the nobles position in the world (motherhood) is behaved by their emotional involvement rather than rational way. Consequently sub-fertile women involve lot of belief and superstition activities. Meditation is the most common practice among both group of Buddhist women and similarly praying is the dominant religious practice among catholic women of both fertile and sub-fertile women. Almost all the Hindu and Islam women involved the invoking blessing of god and praying respectively. In spite of the religion, Invoking blessing of god was the most common practice of all the women in two groups in our study. In general sub-fertile women refer to the religious practices than fertile. Moreover some previous studies have stated that yoga can improve the reproductive health including fertility(48,49). But least percentages of women in both groups involve in yoga.
Even though lifestyle factors have great impact on fertility, certain important factors like dietary habits were excluded in our study due to resource constrains. Therefore studies on fertility should be more concentrated on behavioural factors including diets, exposure to the electromagnetic field, radiation and toxic chemicals in foods in future studies in Sri Lanka. Furthermore we assessed the physical activity through a questionnaire. But the accuracy of data is depending on the recall ability of the participants and this was another limitation of the study. Objective measurements by accelerometers or direct observations are suggested to overcome such drawbacks.