LMP

LMP is an acronym with several meanings across different fields. In medicine, LMP stands for the last menstrual period, the date of the first day of a woman’s most recent menstrual bleed. This date is used to estimate gestational age and to calculate the expected due date. In obstetric practice, gestational age is typically counted in weeks from the LMP, although ultrasound measurements can refine dating when the LMP is uncertain or cycles are irregular. Date estimation influences prenatal screening, timing of tests, and terminology such as first, second, and third trimesters. Limitations include reliance on patient recall and the assumption of regular cycles.

In energy markets, LMP stands for locational marginal price. This is the price of delivering an incremental unit of electrical energy at a specific location on the grid at a specific time, reflecting the marginal cost of energy, losses, and any transmission constraints. LMP prices are calculated by independent system operators or regional transmission organizations and vary by node and hour, producing spatial and temporal price signals that guide generation dispatch, grid operation, and market bidding. LMPs help represent congestion and losses explicitly, though they can be volatile and sensitive to market conditions.

Other uses exist in various technical domains, but the two definitions above are among the most common. Depending on context, LMP may refer to different concepts in a given field, so clarification is typically necessary.