1. What is the Due Date Calculation?

The pregnancy due date is typically calculated as 280 days (40 weeks) from the first day of the last menstrual period (LMP). This is known as Naegele's rule and is the standard method for estimating due dates.

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 gestation

Explanation: The calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. It also tracks your current pregnancy progress.

3. Importance of Due Date Estimation

Details: Knowing your estimated due date helps healthcare providers monitor fetal development, schedule important prenatal tests, and prepare 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 (LMP) in the format MM/DD/YYYY. The calculator will display your estimated due date and current pregnancy progress.

5. Frequently Asked Questions (FAQ)

Q1: What if my cycle isn't 28 days?
A: The calculation can be adjusted by adding or subtracting days based on your typical cycle length (e.g., for 30-day cycles, add 2 days to LMP).

Q2: How accurate is this calculation?
A: It's a general estimate. Ultrasound dating in the first trimester is more accurate (within 5-7 days).

Q3: What's considered full term?
A: Between 37 weeks (259 days) and 42 weeks (294 days) is considered full term.

Q4: Can I calculate from conception date?
A: Yes, add 266 days (38 weeks) to conception date, but LMP is more commonly known.

Q5: Why 280 days if pregnancy is 9 months?
A: 280 days equals 40 weeks, which is about 9 calendar months plus one week.