Rationale and Design of the NPAC-India Study: A Prospective Multicenter Observational Study of Pregnant Women With Heart Disease.

Cardiovascular disease (CVD) is a leading and preventable cause of maternal mortality in low and middle-income countries (LMICs), yet most management guidelines rely on data from high-income countries. Robust, nationally representative data on pregnant women with heart disease (PWHD) are limited in India, underscoring the need for locally relevant evidence to guide clinical practice and policy. The National Pregnancy and Cardiac Disease Study in India (NPAC-India) is a multiphase national initiative, and this paper describes the protocol for Phase 1, a prospective multicenter observational study initiated at 56 sites across India. All consecutive pregnant women presenting for antenatal care with known or newly diagnosed cardiovascular diseases, including congenital or acquired structural heart disease, cardiac arrhythmia, ischemic heart disease, aortopathies, or pulmonary vascular disease, will be enrolled from July 2024. Clinical details related to antenatal, intranatal, and postnatal care will be systematically documented. All study participants will be followed up for 6 months after the end of their pregnancy. The primary outcome is a composite of maternal cardiac events during pregnancy and up to 6 weeks postpartum. The secondary outcomes cover obstetric and fetal parameters. The study will evaluate the predictive accuracy of widely used general and lesion-specific risk assessment tools in the Indian population and explore the development and validation of a population-specific risk stratification model. The NPAC-India study is expected to facilitate the development of evidence-based, locally tailored guidelines for managing heart disease in pregnancy, thereby reducing maternal and fetal risks in India. The generation of national data may strengthen clinical care, improve resource allocation, and inform public health policy.