A rare case of sacral agenesis following undiagnosed pre-existing diabetes complicating pregnancy

Sacral agenesis, or caudal regression syndrome, is a rare congenital malformation affecting the lower spine and associated structures, strongly linked to poorly controlled maternal diabetes. The estimated prevalence is 1–2.5 per 100,000 live births, but the risk increases markedly with maternal pregestational diabetes.We report a case of a 24-year-old primigravida with previously undiagnosed diabetes, identified at booking with HbA1c of 12%. A 12-week ultrasound raised suspicion of spinal abnormality, confirmed at 22 weeks, showing sacral agenesis with encephalocele, absent lower spine, bilateral clubfoot, and oligohydramnios. Pregnancy was complicated by poor glycaemic control, fetal growth restriction, infection, hypertensive disorder, and maternal psychiatric illness.Due to maternal deterioration, preterm delivery was performed at 33 weeks. Postnatal imaging confirmed sacral agenesis with renal and musculoskeletal anomalies . This case highlights the importance of preconception screening, glycaemic optimization, and early anomaly detection in high-risk pregnancies .