1. What is Perinatology Date Calculator?

The Perinatology Date Calculator estimates the due date (EDD) based on the last menstrual period (LMP) using the standard formula of LMP plus 280 days. This is a fundamental tool in obstetric care for pregnancy dating and monitoring.

2. How Does the Calculator Work?

The calculator uses the standard obstetric formula:

Where:

• \( EDD \) — Estimated Due Date
• \( LMP \) — Last Menstrual Period
• \( 280 \) — Standard duration of pregnancy in days (40 weeks)

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

3. Importance of EDD Calculation

Details: Accurate due date calculation is essential for proper prenatal care, monitoring fetal development, scheduling important tests, and determining gestational age for clinical decisions.

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-based due date?
A: LMP-based dating is generally accurate for women with regular 28-day cycles. Ultrasound dating in the first trimester is more precise.

Q2: What if my menstrual cycle is longer or shorter than 28 days?
A: For irregular cycles, the due date may need adjustment. Consult with your healthcare provider for accurate dating.

Q3: Why 280 days instead of 9 months?
A: 280 days equals 40 weeks, which is the standard medical calculation. Calendar months vary in length, so weeks are more precise.

Q4: When should I confirm my due date with ultrasound?
A: First-trimester ultrasound (before 14 weeks) provides the most accurate dating and is recommended to confirm LMP-based calculations.

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 births occur within two weeks before or after the calculated date.