**1. Introduction**

Each natural ovulatory menstrual cycle has a 25% probability of spontaneous conception. Infertility is investigated when there is failure to conceive naturally following 1 year of unprotected intercourse in cases where the female is ≤35 years of age or following 6 months of unprotected intercourse for women >35 years of age. In 40% of the cases it can result due to female factor, in another 20% of cases it's the male factor, which is the cause, and combined factors can cause infertility in about 20% of cases. The causative female factors can be further classified into tubal factors (40%), ovulatory factors (40%), uterine factors (10%) and cervical factors (10%). The commonest etiology of female infertility is ovulation dysfunctions and fallopian tube anatomical and physiological obstruction. The cornerstone first line examinations and investigations for the subfertile couple should detect of ovulation and pituitary and ovarian secretion of hormones by hormonal assay (early follicular FSH and LH levels, mid-luteal progesterone) to assess the endogenous hypothalamo-pituitary-ovarian endometrial axis, and evaluation of tubal patency and function by diagnostic hysterolaparoscopy. GnRH hormone in hypothalamopituitary portal circulation cannot be detected in peripheral blood samples.
