Family Health History Completeness in Prenatal Genetic Counseling: An Exploratory Study at a Single University Hospital.

Family health history (FHH) is essential for genomic medicine and risk assessment, but its completeness in Japanese prenatal settings is poorly understood. Prior studies show that details such as cause of death (COD) and age at onset are often missing. To address this gap, we conducted a pilot observational exploratory study evaluating FHH completeness in a Japanese prenatal genetic counseling setting. We analyzed data from 24 participants (12 couples) who underwent prenatal genetic counseling at a university hospital, most of whom were of advanced maternal age and had undergone non-invasive prenatal testing (NIPT). FHH was collected using a structured form at the first visit and revised at the second visit. Completeness was assessed for four items: medical history, age at death, COD, and age at disease onset. Associations with participant characteristics were also explored. Disease history was most complete, while COD and age at onset were frequently missing. Age at death was more complete than COD, indicating that information on deceased relatives or timelines was harder to obtain. Participants with personal or family medical conditions tended to provide more complete FHH. The structured form and opportunity for revision likely enhanced completeness. This pilot study shows that COD and age at onset are the least complete components of FHH in Japanese prenatal counseling. The small sample size and single-hospital setting limit the generalizability of the findings, but they suggest that structured prompts and preparation before visits may improve FHH completeness and enhance risk assessment in clinical practice.