Utility of Whole Genome Sequencing in Fetuses With Abnormal Ultrasound Findings

Inclusion Criteria: 1. Pregnant women aged ≥ 18 years. 2. Singleton pregnancy. 3. Gestational age between 11+0 and 32+0 weeks, with ultrasound or MRI indicating a definite structural malformation in the fetus (may be with or without soft marker abnormalities) requiring prenatal diagnosis (see Appendices 1 and 2). Fetal developmental abnormalities include those of the central nervous system, cardiovascular system, craniofacial/neck region, chest/mediastinum, abdomen/digestive tract, urinary system, skeletal system/limbs, and systemic abnormalities such as fetal hydrops, abnormally thickened placenta with hydrops, and severe growth restriction. Criteria for ultrasound soft markers and structural malformations are provided in the appendices. 4. Planned to undergo at least one invasive or postnatal procedure for genetic diagnosis, and consent to the use of residual diagnostic samples for research testing. 5. Signed unified informed consent form, agreement to follow-up, and consent for storage and submission of samples and data according to the protocol. Exclusion Criteria: 1. Age \< 18 years or individuals lacking full capacity for civil conduct. 2. Twin or multiple pregnancies. 3. Known parental or familial carrier status of a pathogenic variant highly consistent with the current fetal phenotype, where testing is planned only for targeted confirmation. 4. Refusal to consent to the storage and use of samples and data for this study. 5. Other conditions deemed unsuitable for participation in this study by the investigator.