1. What is Weeks of Pregnancy Calculation?

The weeks of pregnancy calculation determines how far along a pregnancy has progressed based on the first day of the last menstrual period (LMP). This is the standard method used by healthcare providers to estimate gestational age.

2. How Does the Calculator Work?

The calculator uses the following calculation:

Where:

• LMP — First day of last menstrual period
• Current Date — Today's date or any date you want to check

Explanation: Pregnancy is calculated from the first day of your last period because ovulation and conception dates can vary, but LMP is typically more reliably known.

3. Importance of Pregnancy Dating

Details: Accurate pregnancy dating is crucial for proper prenatal care, timing of tests, monitoring fetal growth, and determining the due date (approximately 40 weeks from LMP).

4. Using the Calculator

Tips: Enter the first day of your last menstrual period and the current date (defaults to today). The calculator will show how many weeks and days pregnant you are.

5. Frequently Asked Questions (FAQ)

Q1: What if I don't know my LMP?
A: If you don't know your LMP, an ultrasound in early pregnancy can estimate gestational age based on fetal measurements.

Q2: Is this calculation accurate for irregular cycles?
A: For women with irregular cycles, the LMP method may be less accurate. Ultrasound dating is recommended in these cases.

Q3: How does this relate to trimesters?
A: First trimester: weeks 1-12, second trimester: weeks 13-28, third trimester: weeks 29-40.

Q4: What if my cycle isn't 28 days?
A: The calculation assumes a 28-day cycle. For significantly different cycles, adjustments may be needed (add or subtract days based on your typical cycle length).

Q5: When should I see a doctor?
A: Schedule your first prenatal visit as soon as you know you're pregnant, typically around 8 weeks gestation.