The clinical features are progressive mental decline, autistic behavior, hand disuse, stereotypic movements and ataxia in girls. The disease does not manifest during the fetal period, so the diagnosis cannot be made definitively by ultrasound, magnetic resonance and serological tests during routine obstetric examinations, and requires chorionic villus puncture or amniocentesis to examine the gene for a definitive diagnosis, but usually, puncture tests are not performed during routine obstetric examinations. For prenatal diagnosis of Rett syndrome, there are usually two cases: a family history of Rett syndrome or a previously diagnosed fetus with the disease. In both cases, after genetic counseling, the pregnant woman should undergo chorionic villus puncture at 11-13 weeks + 6 days or amniocentesis at 17-22 weeks to test for the MECP2 gene and terminate the pregnancy if the test results are determined to be abnormal. Pregnant women and their family members who have concerns in this area should consult their doctor in a timely manner and decide whether the appropriate test is needed based on the doctor’s recommendation to avoid unnecessary worries and mood swings that could have adverse effects on the fetus.