Exploring seasonal variation of conception in India: a directional data analysis approach

Seasonal variations in conception and birth have been frequently reported within the global human population. Although births occur throughout the year, certain months record consistently higher frequencies than others. Seasonal variation of conception/birth is a complex phenomenon; numerous factors like climate change, geographical conditions, and environmental factors (temperature, rainfall, and humidity) may affect the risk of conception. This study examined the seasonality of conception in two Indian states, Uttar Pradesh and Kerala, using directional data analysis techniques. Two general patterns were observed: the excess conception for Uttar Pradesh is in November, which is the start of winter in Uttar Pradesh, while in Kerala, excess conception is observed in August, which is the start of the monsoon season. Seasonality of conception in major socio-economic groups (Religion, Cast, Wealth, and Residence) is also observed. This study used the NFHS dataset for the analysis from 1990 to 2018.