Diagnostic criteria: 1 year of cohabitation and no pregnancy; the patient has evidence of ovulation; the male partner has normal semen examination; laparoscopy confirms no abnormality in the female partner’s pelvis. Treatment: 1. ovulation promotion: clomiphene is preferred; 2. ovulation induction + intrauterine insemination: after clomiphene is ineffective; 3. in vitro fertilization (IVF-ET): after three failed intrauterine inseminations.