1. What is the Pregnancy Duration Calculator?

The Pregnancy Duration Calculator estimates how far along you are in your pregnancy based on your last menstrual period (LMP) and current date. It calculates the number of weeks of pregnancy using standard obstetric dating methods.

2. How Does the Calculator Work?

The calculator uses the pregnancy duration formula:

Where:

• \( FA \) — Far along in pregnancy (weeks)
• \( CD \) — Current date
• \( LMP \) — Last menstrual period date
• \( \lfloor \rfloor \) — Floor function (rounding down to nearest whole number)

Explanation: The calculation determines the number of complete weeks that have passed since the first day of your last menstrual period, which is the standard method for dating pregnancies in obstetrics.

3. Importance of Pregnancy Dating

Details: Accurate pregnancy dating is essential for monitoring fetal development, scheduling prenatal tests at appropriate times, determining due dates, and identifying potential complications related to gestational age.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period and today's date. Ensure dates are entered correctly for accurate results. The calculator will show how many complete weeks of pregnancy have passed.

5. Frequently Asked Questions (FAQ)

Q1: Why use LMP instead of conception date?
A: LMP is used because it's typically more reliably known than conception date and is the standard method in obstetrics for pregnancy dating worldwide.

Q2: How accurate is this calculation?
A: This provides a good estimate, but ultrasound dating in early pregnancy (especially first trimester) is more accurate for determining gestational age.

Q3: What if I have irregular periods?
A: If you have irregular cycles, LMP dating may be less accurate. An early ultrasound provides the most reliable dating in these cases.

Q4: When should I see a healthcare provider?
A: Schedule your first prenatal appointment as soon as you suspect pregnancy, typically around 8 weeks gestation based on LMP calculation.

Q5: How is due date calculated from this?
A: Estimated due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period.