The In-Vivo and In-Vitro Effects of Sildenafil (Viagra) on Oocyte and Embryo Development - Literature review Example

Boivin et al. (2007) revealed that roughly 80 million couples around the world are having difficulty conceiving a child. In UK, the NHS reported that around 3.5 million individuals or one out of six couples are facing problems related to infertility (NHS, 2012). There are quite a lot of factors that can lead to infertility. Based on the study that was conducted by the World Health Organization (WHO), these factors were identified as: female reproductive disorders (38%), biological abnormalities in men and women (27%), male reproductive disorder (20%), subfertility (10-15%), and unknown causes (15%) (Kretser, 1997).

The term “idiopathic” means that there is no specific known cause for a given disorder (Falcone, 2006, p. 58). Therefore, idiopathic amenorrhoea means that there is an unknown cause behind the absence of menstruation. Although problems related to infertility may not cause serious threat on the physical health of a couple, it will always remain a fact that their inability to conceive a child may trigger serious harm on their social and mental well-being. Among the common factors that causes infertility among women of reproductive age includes: fallopian tube problems (27.4%), unknown causes (24.5%), menstrual disorder (20%), uterus disorder (9.1%), sexual disorder (2.7%), age factor (2.7%), and the risk of ovarian failure (<1%) (Roupa et al., 2009). In some cases, disturbances in women’s ovulation cycle, endometriosis, cervical- and uterine-related problems, metabolic disorders, and the presence of tuboperitoneal or tubal disorders can also lead to female infertility problems (Boivin et al.

, 2009; Maheshwari, Hamilton and Bhattacharya, 2008; Falcone, 2006, p. 58; Hamilton-Fairley and Taylor, 2003; Evers, 2002). As a type of subfertility problem in adolescent women, ovulation disturbances can occur because of excessive physical, mental, and social stress, lack of exercise, poor diet, and overweight (Chrisler, 2004, pp. 199 – 200; Farr et al., 2004). In the case of menopausal women, ovulation disturbances can occur because of excessively high levels of oestrogen. Other possible causes of ovulatory disturbances include not only the risk of developing polycystic ovary syndrome (PCOS) but also excessive production prolactin hormone and the presence of thyroid disease (Falcone, 2006, p. 58). For example, the presence of thyroid diseases such as hypothyroidism can make women experience anovulation (Legato, 2010, p. 382).