1. What is the Naegele's Rule?

The Naegele's Rule is a standard way to calculate the estimated due date (EDD) for a pregnancy. It assumes a 28-day menstrual cycle with ovulation occurring on day 14. The rule adds 280 days (40 weeks) to the first day of the last menstrual period (LMP).

2. How Does the Calculator Work?

The calculator uses Naegele's Rule:

Where:

• LMP — First day of last menstrual period
• 280 days — Equivalent to 40 weeks of gestation

Explanation: This calculation estimates the date when the pregnancy will reach 40 weeks, which is considered full term.

3. Importance of Due Date Calculation

Details: Accurate due date estimation is crucial for prenatal care, monitoring fetal development, and planning for delivery. It helps identify preterm or post-term pregnancies that may need special attention.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period (LMP) in the format YYYY-MM-DD. The calculator will add 280 days (40 weeks) to estimate your due date.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: It's an estimate - only about 5% of women deliver on their exact due date. Most deliver within 2 weeks before or after.

Q2: What if my cycle isn't 28 days?
A: The calculation adjusts automatically if you know your ovulation date (due date = ovulation date + 266 days).

Q3: Why do doctors use LMP instead of conception date?
A: LMP is typically more reliably known than conception date, and it's been the standard reference point for centuries.

Q4: How does ultrasound dating compare?
A: First-trimester ultrasound is more accurate and may adjust the due date, especially if LMP is uncertain or cycles are irregular.

Q5: What's considered full term?
A: 39-40 weeks is full term, 37-38 weeks is early term, and 41+ weeks is late term.