1. What Is Pregnancy Calculation?

Pregnancy calculation estimates the due date based on the first day of the last menstrual period (LMP). The standard method adds 280 days (40 weeks) to the LMP date to determine the estimated due date (EDD).

2. How Does The Calculator Work?

The calculator uses the standard pregnancy calculation formula:

Where:

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

Explanation: This calculation assumes a regular 28-day menstrual cycle and ovulation occurring on day 14. The 280 days represent 40 weeks of gestation.

3. Importance Of Pregnancy Dating

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

4. Using The Calculator

Tips: Enter the first day of your last menstrual period. The calculator will provide the estimated due date. Remember that this is an estimate and actual delivery may vary.

5. Frequently Asked Questions (FAQ)

Q1: Why is pregnancy calculated from LMP instead of conception?
A: LMP is used because it's a definite date that most women can recall, while the exact conception date is often unknown.

Q2: How accurate is the 280-day calculation?
A: It's a general estimate. Only about 5% of women deliver exactly on their due date, with most delivering within 2 weeks before or after.

Q3: What if my menstrual cycle is irregular?
A: For irregular cycles, early ultrasound dating is more accurate than LMP-based calculation.

Q4: Can the due date change during pregnancy?
A: Yes, healthcare providers may adjust the due date based on early ultrasound measurements, which are more accurate in the first trimester.

Q5: What is Naegele's rule?
A: This is the traditional method: add 7 days to LMP, then subtract 3 months. Both methods give similar results.