1. What is the Due Date Calculation?

The due date calculation estimates the date of delivery by adding 280 days (40 weeks) to the first day of the last menstrual period (LMP). This is based on the typical human gestation period.

2. How Does the Calculator Work?

The calculator uses the standard pregnancy due date formula:

Where:

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

Explanation: This calculation (Naegele's rule) assumes a regular 28-day menstrual cycle with ovulation occurring on day 14.

3. Importance of Due Date Estimation

Details: Accurate due date estimation helps in monitoring fetal development, scheduling prenatal tests, and preparing for delivery. Only about 5% of women deliver on their exact due date.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period. 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 provides a general estimate. Ultrasound dating in the first trimester is more accurate for establishing gestational age.

Q2: What if my cycle isn't 28 days?
A: For irregular or longer cycles, the calculation may need adjustment. Consult your healthcare provider.

Q3: What's considered full term?
A: Between 37 weeks and 41 weeks 6 days. Babies born before 37 weeks are preterm, after 42 weeks are post-term.

Q4: Can the due date change?
A: Yes, early ultrasound may lead to adjustment of the due date based on fetal measurements.

Q5: Why 280 days if pregnancy is 9 months?
A: Pregnancy is actually about 9.5 months when calculated by weeks (40 weeks × 7 days = 280 days).