For the natural conception couple needs healthy female eggs and male sperms of good quality and count and the working sexual functions. There are few factors that become hindrance for your way to happy pregnancy
Decreased healthy eggs
Females born with the fixed number of eggs and these eggs can decline with the age. Aging can also deplete the health of eggs. According to studies women with the age more than 30 have reduced chances of pregnancy due to poor egg quality even after having good health and fertility.
Your partner can have issues
For successful conception male partner plays the vital role so the problem of partner can also become hindrance for the natural conception as males can have problem with the count of sperms and quality of sperms. In few cases male sperms have inability to penetrate the female eggs and to fertilize them.
Ovulation can also increase your problem for getting pregnant. If the women have disturbed menstrual cycles then it can be main cause for her fertility issues.
Blocked fallopian tubes
Fallopian tubes are medium for the communication of female eggs and sperm. So blocked and damaged fallopian tubes block the way for the sperm to reach to egg and to fertilize it.