The early embryo can die of inherited or spontaneous malformation, before it implants. Sometimes the lining of the uterus is not properly prepared for the embryo. In some cases, the immune defense system of the mother rejects the embryo as a foreign protein.

If no medical reasons for infertility can be found in neither the man nor the woman, we call this an unclearified infertility. In such cases the psychosomatic aspects should be taken into consideration. We have learned that emotional components can sometimes interfere with body functions. If this is the case, a psychotherapeutic clarification is advisable, after which the right steps may lead to success (also see: psychological advice).