1. What is the Pregnancy 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 the standard formula:

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. The calculator also shows current gestational age based on today's date.

3. Importance of Due Date Calculation

Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, and determining if pregnancy is progressing normally. It helps identify preterm or post-term pregnancies.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the due date calculation?
A: Only about 5% of women deliver on their exact due date. Most deliver within 2 weeks before or after the estimated date.

Q2: What if my cycles aren't 28 days?
A: For women with irregular cycles, the due date may need adjustment. An early ultrasound can provide a more accurate estimate.

Q3: Why is 280 days used if pregnancy is 9 months?
A: Pregnancy is actually about 9.5 months. 280 days accounts for the full gestation period from LMP, including the 2 weeks before conception.

Q4: How is gestational age different from fetal age?
A: Gestational age counts from LMP, while fetal age counts from conception (about 2 weeks later). Medical professionals use gestational age.

Q5: When should I contact my doctor about my due date?
A: If you're uncertain about your LMP or have irregular cycles, consult your doctor. An ultrasound can confirm dates, especially if done in first trimester.