1. What is the Pregnancy Due Date Calculator?

The Pregnancy Due Date Calculator estimates the expected delivery date based on the first day of your last menstrual period (LMP), adding 280 days (40 weeks) as per the What to Expect method.

2. How Does the Calculator Work?

The calculator uses the standard pregnancy calculation:

Where:

• \( \text{LMP} \) — First day of last menstrual period
• \( 280 \text{ days} \) — Standard length of pregnancy (40 weeks)

Explanation: This calculation assumes a regular 28-day menstrual cycle with ovulation occurring on day 14. Only about 5% of women deliver on their exact due date.

3. Importance of Due Date Calculation

Details: Knowing your estimated due date helps track pregnancy milestones, schedule prenatal care, and monitor fetal development. It's also important for planning maternity leave and preparing for delivery.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period (LMP) in the format MM/DD/YYYY. The calculator will show your estimated due date and how many days/weeks remain until that date.

5. Frequently Asked Questions (FAQ)

Q1: What if I don't know my LMP?
A: If you're unsure of your LMP, an early ultrasound can provide a more accurate due date estimate.

Q2: Is 280 days exact for everyone?
A: No, pregnancy length can vary. First pregnancies often last longer, while subsequent pregnancies may be shorter.

Q3: What if my cycles aren't 28 days?
A: The calculation adjusts automatically if you know your ovulation date (due date = ovulation date + 266 days).

Q4: When will my doctor adjust my due date?
A: Doctors may adjust based on early ultrasound measurements, especially if they differ significantly from LMP calculation.

Q5: What's considered "full term"?
A: Between 37 weeks (259 days) and 42 weeks (294 days). Most babies are born within this window.