1. What is LMP Calculation?

The Last Menstrual Period (LMP) calculation estimates the first day of a woman's last menstrual period based on the due date. This is important for tracking pregnancy progress and estimating conception date.

2. How Does the Calculator Work?

The calculator uses the standard pregnancy duration:

Where:

• \( LMP \) — First day of last menstrual period
• \( Due\ Date \) — Estimated delivery date
• \( 280\ days \) — Standard duration of human pregnancy (40 weeks)

Explanation: This calculation assumes a standard 28-day menstrual cycle with ovulation occurring on day 14.

3. Importance of LMP Calculation

Details: Knowing the LMP helps healthcare providers track fetal development, schedule important tests, and monitor the pregnancy timeline. It's also used to calculate gestational age.

4. Using the Calculator

Tips: Enter the estimated due date (from ultrasound or doctor's estimate) to calculate the corresponding LMP. The result will show the first day of your last period before conception.

5. Frequently Asked Questions (FAQ)

Q1: Why 280 days?
A: 280 days (40 weeks) is the standard duration used to calculate pregnancy from LMP, though actual delivery dates vary.

Q2: What if my cycle isn't 28 days?
A: This calculation assumes a 28-day cycle. Women with longer/shorter cycles may need adjustment based on their typical cycle length.

Q3: How accurate is this calculation?
A: It provides an estimate. Ultrasound measurements in early pregnancy are more accurate for dating.

Q4: Can I use this to find my conception date?
A: Conception typically occurs about 14 days after LMP in a 28-day cycle, but this varies by individual.

Q5: What if I don't know my due date?
A: An ultrasound can provide an estimated due date which you can then use with this calculator.