1. What is LMP Calculator Wheel?

The LMP (Last Menstrual Period) Calculator Wheel estimates the due date of pregnancy based on the first day of the woman's last menstrual period. It uses the standard calculation of adding 280 days (40 weeks) to the LMP date.

2. How Does the Calculator Work?

The calculator uses the standard obstetric formula:

Where:

• \( LMP \) — First day of last menstrual period
• \( EDD \) — Estimated due date
• \( 280 \text{ days} \) — Standard pregnancy duration (40 weeks)

Explanation: This calculation is based on Naegele's rule, which assumes a 28-day menstrual cycle with ovulation occurring on day 14.

3. Importance of EDD Calculation

Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, scheduling important tests, and preparing for delivery.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period in the date field. The calculator will automatically compute your estimated due date based on the standard 280-day pregnancy duration.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the LMP method?
A: The LMP method provides a good estimate but may be less accurate for women with irregular cycles. Ultrasound dating in the first trimester is more precise.

Q2: What if I don't know my LMP exactly?
A: If you're unsure of your LMP, an early pregnancy ultrasound (6-12 weeks) can provide a more accurate due date estimation.

Q3: Why 280 days instead of 9 months?
A: Pregnancy is calculated as 40 weeks from LMP, which equals 280 days. This accounts for the fact that conception typically occurs about 2 weeks after LMP.

Q4: Can my due date change?
A: Yes, healthcare providers may adjust the due date based on early ultrasound measurements or if the LMP date seems inconsistent with fetal size.

Q5: What percentage of babies are born on their due date?
A: Only about 5% of babies are born exactly on their due date. Most are born within two weeks before or after the estimated date.