1. What Is Fetal Age Calculation?

Fetal age calculation determines how many weeks pregnant you are based on your last menstrual period (LMP). This is the standard method used by healthcare providers to track pregnancy progress and estimate due dates.

2. How Does The Calculator Work?

The calculator uses the pregnancy dating formula:

Where:

• \( Current Date \) — Today's date or any specified date
• \( LMP \) — First day of last menstrual period
• \( \lfloor \rfloor \) — Floor function (rounds down to nearest whole number)

Explanation: The calculation counts the number of complete weeks that have passed since the first day of your last menstrual period.

3. Importance Of Pregnancy Dating

Details: Accurate pregnancy dating is essential for monitoring fetal development, scheduling prenatal tests at appropriate times, determining viability, and estimating the expected delivery date.

4. Using The Calculator

Tips: Enter the first day of your last menstrual period and the current date (or any date you want to check). 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 most women know when their last period started, while conception date is often uncertain. Medical standards use LMP for consistency.

Q2: What if I don't know my exact LMP?
A: Use your best estimate. An ultrasound in early pregnancy can provide a more accurate gestational age if LMP is uncertain.

Q3: How accurate is this calculation?
A: Very accurate for women with regular 28-day cycles. Variations may occur with irregular cycles or uncertain LMP dates.

Q4: When should I see a doctor for confirmation?
A: Schedule your first prenatal appointment around 8 weeks for confirmation via ultrasound and comprehensive pregnancy care.

Q5: Does this work for IVF pregnancies?
A: For IVF pregnancies, gestational age is calculated from embryo transfer date plus 14 days (or egg retrieval date plus 14 days).