## Epidemiology of Neural Tube Defects in India **Key Point:** Anencephaly is the most common neural tube defect (NTD) in the Indian population, followed by spina bifida and encephalocele. This is consistent with both Indian registry data and global epidemiological studies. ### Prevalence Ranking in India | Defect | Relative Frequency | Notes | |---|---|---| | **Anencephaly** | Most common | ~50–60% of all NTDs in India | | Spina bifida (cystica/occulta) | Second most common | Includes meningocele & myelomeningocele | | Encephalocele | Rare | Occipital most common subtype | | Iniencephaly | Very rare | <0.1 per 1000 live births | **High-Yield:** Anencephaly results from failure of closure of the **rostral (cranial) neuropore** by day 24–26 of gestation. It is uniformly lethal — affected fetuses are either stillborn or die within hours to days of birth. **Clinical Pearl:** In India, the overall NTD incidence is approximately 1.9–4 per 1000 live births depending on the region and study. Anencephaly consistently accounts for the largest single category of NTDs in Indian hospital-based and community-based registries (e.g., ICMR collaborative studies, Bhide et al.). **Why not Spina Bifida Cystica?** While spina bifida cystica (myelomeningocele/meningocele) is the most common *survivable* NTD and the most common NTD seen in pediatric/neurosurgical practice, anencephaly is the most common NTD *overall* in terms of incidence at birth in India — a distinction frequently tested in NEET PG / INI-CET. **Reference:** Sadler TW, *Langman's Medical Embryology*, 14th ed.; ICMR Task Force on Neural Tube Defects; Park K, *Textbook of Preventive and Social Medicine*, 26th ed.
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.