1. What is the Perinatology Due Date Calculation?

The perinatology method calculates pregnancy due date by adding 280 days (40 weeks) to the first day of the last menstrual period (LMP). This is based on the standard human gestation period and is widely used in obstetrics.

2. How Does the Calculator Work?

The calculator uses the perinatology formula:

Where:

• LMP — First day of last menstrual period
• 280 days — Standard gestation period (40 weeks)

Explanation: This calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. The actual conception date is typically about 2 weeks after the LMP.

3. Importance of Due Date Calculation

Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, scheduling tests, and determining if a pregnancy is post-term.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period in YYYY-MM-DD format. The calculator will show your estimated due date and current gestational age.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: It's accurate for women with regular 28-day cycles. Ultrasound dating may be needed for irregular cycles.

Q2: What if I don't know my LMP?
A: An early ultrasound (first trimester) can provide the most accurate dating.

Q3: Why 280 days if pregnancy is 9 months?
A: Pregnancy is actually about 9.5 lunar months (40 weeks). Months vary in length while weeks don't.

Q4: What percentage of babies are born on their due date?
A: Only about 5%. Most births occur within 2 weeks before or after the due date.

Q5: How does this differ from Naegele's rule?
A: Perinatology uses 280 days while Naegele's adds 7 days to LMP then 9 months (slightly different results).