1. What Is LMP Calculator Based On Due Date?

The LMP (Last Menstrual Period) Calculator Based On Due Date calculates the start date of the last menstrual period when the estimated due date is known. This is useful for pregnancy dating and determining gestational age.

2. How Does The Calculator Work?

The calculator uses the standard pregnancy calculation formula:

Where:

• \( LMP \) — Last Menstrual Period (date)
• \( EDD \) — Estimated Due Date (date)
• \( 280 \) — Standard pregnancy duration in days

Explanation: This calculation is based on Naegele's rule, which assumes a 280-day (40-week) pregnancy from the first day of the last menstrual period.

3. Importance Of LMP Calculation

Details: Accurate LMP calculation is essential for determining gestational age, scheduling prenatal tests, monitoring fetal development, and planning for delivery.

4. Using The Calculator

Tips: Enter the estimated due date in the date field. The calculator will automatically compute the corresponding last menstrual period date by subtracting 280 days.

5. Frequently Asked Questions (FAQ)

Q1: Why is 280 days used for pregnancy calculation?
A: 280 days represents the standard 40-week gestational period calculated from the first day of the last menstrual period in a typical 28-day cycle.

Q2: How accurate is this calculation?
A: This provides an estimate. Actual pregnancy duration can vary, and ultrasound dating may provide more accurate gestational age assessment.

Q3: What if my menstrual cycle is not 28 days?
A: For women with irregular or longer cycles, the calculation may need adjustment. Consult with a healthcare provider for personalized assessment.

Q4: Can this be used for IVF pregnancies?
A: For IVF pregnancies, the conception date is known precisely, so different calculation methods are typically used.

Q5: When should I confirm with ultrasound?
A: Early pregnancy ultrasound (first trimester) provides the most accurate dating and is recommended to confirm gestational age.