Naegle's rule is primarily used to calculate what in obstetrics?

Naegle's rule is primarily used to estimate the due date of a pregnancy. This calculation involves taking the first day of the woman's last menstrual period (LMP), adding one year, subtracting three months, and then adding seven days. This method provides a quick and straightforward way to estimate the date when the baby is expected to be born, typically around 40 weeks after the LMP.

The accuracy of Naegle's rule relies on the assumption that the woman has a regular 28-day menstrual cycle and ovulates roughly 14 days after the onset of her last period. It is important for healthcare providers to utilize this rule as part of prenatal care to help women understand their pregnancy timeline and plan for the delivery.

By focusing specifically on the due date, Naegle's rule serves as a fundamental tool in obstetrics, helping both the healthcare provider and the patient align on expectations for prenatal visits, infant care, and delivery preparation.