Study Guides/General Knowledge/LMP Full Form — Last Menstrual Period
Study Guide · General Knowledge

LMP Full Form

LMP full form is Last Menstrual Period. The LMP date is the first day of a woman's last menstrual period before pregnancy. It is used by doctors to calculate the Expected Date of Delivery (EDD) and gestational age of the baby. Using Naegele's Rule: EDD = LMP date + 9 months + 7 days (or + 280 days).

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What is the full form of LMP?

Answer

LMP full form is Last Menstrual Period — the first day of a woman's last menstrual period before pregnancy. Doctors use the LMP date to calculate the Expected Date of Delivery (EDD) using Naegele's Rule: EDD = LMP + 9 months + 7 days (or + 280 days). Gestational age is also counted from the LMP date.

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Key Facts

LMP full form = Last Menstrual Period.

LMP date used to calculate EDD (Expected Date of Delivery) and gestational age.

Naegele's Rule: EDD = LMP + 9 months + 7 days (or + 280 days).

Pregnancy is 40 weeks (280 days) counted from LMP date.

Gestational age = weeks elapsed since LMP.

Conception occurs ~2 weeks after LMP.

LMP — Full Form, Calculation, and Medical Use

Full Form: Last Menstrual Period Hindi: अंतिम माहवारी (Antim Mahavari)

Why is LMP Important in Pregnancy? • Doctors use LMP to calculate:

  1. Gestational age (age of the baby in weeks)
  2. Expected Date of Delivery (EDD / Due Date) • Pregnancy is calculated from the first day of LMP, not conception • Standard pregnancy = 40 weeks (280 days) from LMP

Naegele's Rule — EDD Calculation from LMP: • EDD = LMP date + 9 months + 7 days • Or: EDD = LMP date + 280 days • Example: LMP = 1 January 2025 → EDD = 1 January + 9 months + 7 days = 8 October 2025

Gestational Age Calculation: • Gestational age = number of weeks since LMP • Example: LMP = 1 January; current date = 1 March → Gestational age ≈ 8–9 weeks

Why LMP and Not Conception Date? • Conception happens ~2 weeks after LMP • LMP is easier for women to track • Doctors use LMP as a standardised reference point

Trimester Timeline from LMP:

TrimesterWeeks from LMP
First Trimester1–12 weeks
Second Trimester13–27 weeks
Third Trimester28–40 weeks

Other Information About LMP: • If cycle is irregular, ultrasound is used to confirm gestational age • Ultrasound in first trimester (7–12 weeks) is most accurate for dating • Early ultrasound may adjust EDD if different from LMP-based calculation

Questions and Answers

What is the full form of LMP?+

LMP full form is Last Menstrual Period — the first day of a woman's last menstrual period before pregnancy. Doctors use the LMP date to calculate the Expected Date of Delivery (EDD) using Naegele's Rule: EDD = LMP + 9 months + 7 days (or + 280 days). Gestational age is also counted from the LMP date.

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