Infertility (sterility) is the incapability of conception during the one or two years of a usual sexual life without the use of contraception. Infertility can be primary (if a woman has never been pregnant) or secondary (if a woman cannot get pregnant after the previous pregnancy).
Reduced fertility (infertility) is the incapability of delivering alive or life capable children (frequent miscarriage, pregnancy without an embryo, dead embryo, and others). Spontaneous miscarriages occur in 15-20% of all pregnancies. During early pregnancy, spontaneous miscarriages often happen because of chromosome changes, and in later pregnancy, the causes are infections, sexually spread diseases, weakened functioning of the placenta, and other.

It is estimated that there are about 15% of infertile couples. In one-third of the cases, the problem is with the woman, in the other third the problem is with the man, and in the final third the problem is among both partners.
The causes of infertility or reduced fertility of the couple can be:
• Maternal (among women), absence of ovulation, infection of the genital tract, tumors, malformations, endometriosis, chronic diseases;
• Paternal (among men), less valued sperm, number, features, and vitality of spermatozoids, infections, tumors, injuries, previous operations;
• Fetal (problems with the fetus), genetic and other malformations not related to life, infections;
• Endocrine (diabetes, thyroid gland diseases, kidney diseases, polycystic ovary syndrome);
• Immune, metabolic, consumption of harmful remedies; genetic incompatibility of the couple.