Infertility: A Physiological Overview And Clinical Significance Of Its Causes, Diagnosis And Treatment

Infertility is defined as inability to achieve pregnancy after one year of normal married life. In primary infertility the women fails to conceive, whereas in secondary infertility, there is evidence of fertility occurring in the past, such as abortion, ectopic gestation or successful childbirth. In large series, the male partner is at fault in 40% and the female partner in 40%. The cause is obscure in 20% cases.

Ovum transport: Normally, the ovulated egg with attached follicular cells passes through the fallopian tubes by ciliary action and reaches the uterus in 60-70 hours, after ovulation. Fertilisation takes place in the ampulla of the tube. After fertilization and extrusion of the second polar body, the ovum becomes impervious to penetration by the other sperms.

Sperm transport: In normal adult, men seminal ejaculate measures 3 to 7 ml and the sperm count is greater than 60 million/ml. More than 60% of sperms show progressive motility at 24 hours after ejaculation and more than 60% sperms have normal morphology. The ejaculated semen rapidly forms a gel and then liquefies. In the female genital tract, the sperms acquire the capcity to penetrate the ovum (capacitation). About 200 sperms rapidly pass into the uterine cavity and the capacitated sperm penetrates the ovum and fertilizes it.

Common causes include sperm counts below 20 million/ml, ejaculate volume below 1.0 ml, infections, failure of liquefaction and sperm agglutination. Temporarily spem counts may be suppressed by factors like fever, systemic illnesses, drug therapy and endocrine disorders.

1. Hypothalamopituitary diseases: Panhypopituitarism or selective FSH deficiency, Hyperprolactinemia, drug like phenytoin, androgens and estrogens.
2. Testicular diseases, testicular atrophy, cryptorchism, varicocele, spermatogenic arrest, drugs like cyclophosphamide and other antimitotic drugs, Autoimmune disorders giving rise to antibodies against testicular basement membranes and sperms
3. Other causes such as infection of the genitourinary tract with bacteriospermia, congenital or acquired ductal obstruction, disorders of ejaculation, eg. Retrograde ejaculation and anatomical defects such as hypospadias.

Treatment: The management of infertility in men involved effective correction of all treatable disorders like varicocele, endocrinopathies and ductal obstruction. Often specialized investigations and prolonged management are necessary to ensure success. Though many cases respond favourably to therapeutic intervention, some remain intractable.

Investigation and management of female infertility is generally done by the gynecologist. Women show maximal fertility from 24 to 35 years. Aim of investigation in female infertility is to detect abnormalities of ovulation, morphological abnormalities of the genital passage and functional abnormalities of the sperms in the vagina. About 30- 40% of cases have pelvic abnormalities like tubal occlusions, adhesions, and endometriosis. Abnormalities of cervical secretions occur in 10- 30%. Uterine abnormalities commonly cause recurrent abortions and are diagnosied by a full gynecological examination. Sometimes immunological abnormalities may develop leading to infertility. There are ABO blood group incompatibility, circulating sperm agglutinating and sperm immobilizing antibodies in women or autoimmune disorders in men.