1. What is the Pregnancy Wheel Calculation?

The pregnancy wheel calculation estimates the due date by adding 280 days (40 weeks) to the first day of the last menstrual period (LMP). This is based on Naegele's rule and is the standard method used by healthcare providers.

2. How Does the Calculator Work?

The calculator uses the standard pregnancy wheel 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 280 days accounts for 266 days of pregnancy plus 14 days from LMP to conception.

3. Importance of Due Date Estimation

Details: Accurate due date estimation is crucial for proper prenatal care, timing of tests, monitoring fetal growth, and planning for delivery. 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 MM/DD/YYYY. The calculator will display your estimated due date and current gestational age.

5. Frequently Asked Questions (FAQ)

Q1: What if my cycles aren't regular?
A: The calculation is most accurate for women with regular 28-day cycles. If your cycles are longer or irregular, an early ultrasound may provide a more accurate due date.

Q2: How accurate is this calculation?
A: Only about 5% of women deliver on their exact due date. Most deliver within 2 weeks before or after the estimated date.

Q3: What if I know my conception date?
A: If you know your conception date, you can calculate by adding 266 days (38 weeks) to that date instead.

Q4: When should I see my healthcare provider?
A: Schedule your first prenatal visit as soon as you have a positive pregnancy test, typically around 8 weeks gestation.

Q5: Can the due date change?
A: Yes, your provider may adjust your due date based on early ultrasound measurements, especially if they differ significantly from the LMP calculation.