1. What is Pregnancy Weeks Calculator?

The Pregnancy Weeks Calculator determines how many weeks pregnant you are based on your last menstrual period (LMP) and current date. This is the standard method used by healthcare providers to estimate gestational age.

2. How Does the Calculator Work?

The calculator uses the following formula:

Where:

• \( LMP \) — Last Menstrual Period (first day of last period)
• \( Current Date \) — Today's date or any specified date
• \( Weeks \) — Complete weeks of pregnancy
• \( \lfloor \rfloor \) — Floor function (rounding down)

Explanation: The calculation counts the number of days from LMP to current date, then divides by 7 to get complete weeks of pregnancy.

3. Importance of Pregnancy Dating

Details: Accurate pregnancy dating is crucial for monitoring fetal development, scheduling prenatal tests, determining due date, and making important healthcare decisions throughout pregnancy.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period and the current date (defaults to today). Ensure dates are entered in the correct format (YYYY-MM-DD) for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: Why is pregnancy calculated from LMP instead of conception?
A: LMP is used because it's easier to pinpoint than conception date. Pregnancy is typically 40 weeks from LMP (38 weeks from conception).

Q2: What if I don't know my exact LMP?
A: If unsure about LMP, an ultrasound in early pregnancy can provide more accurate dating based on fetal measurements.

Q3: How accurate is this calculation?
A: This method is standard but may vary if you have irregular cycles. Ultrasound confirmation is recommended for precise dating.

Q4: What are the pregnancy trimesters?
A: First trimester: weeks 1-13, Second trimester: weeks 14-27, Third trimester: weeks 28-40+.

Q5: When should I see a healthcare provider?
A: Schedule your first prenatal appointment as soon as you suspect pregnancy, typically around 8 weeks from LMP.