Inclusion Criteria:  Postnatal age less than 100 days; Perinatal death after 20 weeks of gestation (more than 500 g) Can be retained biological samples for genetic screening; Biological parent or guardian's informed consent.  Exclusion Criteria:  Reluctance of parents to use genetic sequencing data for subsequent research; Parents under 18 years of age or incapacitated for decision-making; subjects older than 100 days; Perinatal death less than 20 weeks of gestation or weight less than 500 g; Inherited metabolic diseases with chromosomal abnormalities; Multiple pregnancies; Lack of access to biological samples from which DNA can be extracted; Failure to sign informed consent.