- The normal count of spermatozoa is 100 million/ml. The minimum count for fertility is 20 million/ml. The production of healthy spermatozoa is necessary to be deposited in vagina.
- The spermatozoa remain healthy and penetrate into the uterine cavity and into the uterine tubes.
- Production of ova is vital. The ovum finds its way into the uterine tube where it can be fertilized by a spermatozoon.
- The fertilized ovum migrates into the uterus and the endometrium should be hospitable for the spermatozoa for the implantation of fertilized ovum.
Causes of Infertility The numerous reasons that lead to infertility can be broadly categorized to be related to the anatomy ( physiological causes) or due to some kinds of infections (pathological causes).
Physiological Infertility is the rule prior to puberty and after menopause. But it should be remembered that the girl may be pregnant even before the menarche and pregnancy is possible within few months of menopause. Fertility is lower until the age of 16–17 years and after 35 years. Conception is impossible during pregnancy as the hormone Human Chorionic Gonadotrophin HCG is suppressed and hence no ovulation. During lactation, infertility is said to be relative. Inspite of the fact that the patient is amenorrhagic during lactation, ovulation and conception can occur. However, in fully lactating women (breast feeding 5–6 times a day and spending 60 minutes in 24 hours), pregnancy is unlikely up to 10 weeks postpartum.
Pathological Conception depends on the fertility of both the male and female partner. It is also emphasized that the relative infertility of one partner may sometimes be counter balanced by the high fertility of the other.Faults in the Female Ovarian Factors
- Anovulation and Oligo–ovulation (infrequent ovulation)
- Corpus Luteum Insufficiency (CLI)
- Lutinization of Unruptured Follicle (LUF)
Anovulation or Oligo–ovulation In the absence of ovulation, conception cannot take place. This is quite frequent during adolescence or premenopausal period. Hypothalamic or Cortical factors Pituitary Gonadal Others Factors are
- Thyroid dysfunction.
- Substantial weight loss (anorexia nervosa).
- Diabetes mellitus.
- Adrenal hyperfunction.
- Pelvic endometriosis.
As there is no ovulation, there is no corpus luteum formation. In the absence of progesterone, there is no secretary endometrium in the second half of the cycle. The other features of ovulation are absent.
Corpus Luteum Insufficiency (CLI) In this condition, there is inadequate growth and function of the corpus luteum. The life span of the corpus luteum is shortened to less than 10 days. There is insufficient secretion of progesterone and hence less secretary changes in the endometrium which hinders implantation.