1. What is Gestational Age?

Gestational age is the common term used during pregnancy to describe how far along the pregnancy is. It is measured in weeks from the first day of the woman's last menstrual period (LMP) to the current date.

2. How Gestational Age is Calculated

The standard calculation for gestational age:

Where:

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

Explanation: Pregnancy is calculated from the first day of your last menstrual period because ovulation and conception dates can be uncertain, but LMP is usually known.

3. Importance of Gestational Age

Details: Knowing the gestational age helps healthcare providers:

• Monitor fetal growth and development
• Schedule important prenatal tests at the right times
• Determine if the baby is growing appropriately
• Plan for delivery
• Identify potential preterm or post-term pregnancies

4. Using the Calculator

Tips:

• Enter the first day of your last menstrual period (LMP)
• Enter the current date (defaults to today)
• The calculator will show gestational age in weeks and days
• LMP date must be before current date

5. Frequently Asked Questions (FAQ)

Q1: Why is gestational age calculated from LMP and not conception?
A: The exact conception date is often unknown, while LMP is usually clearly remembered. This provides a consistent starting point for all pregnancies.

Q2: What if I don't know my LMP?
A: An ultrasound in early pregnancy can estimate gestational age based on fetal measurements.

Q3: How accurate is this calculation?
A: It assumes a regular 28-day cycle with ovulation on day 14. Variations in cycle length may affect accuracy.

Q4: What's the difference between gestational age and fetal age?
A: Fetal age is the actual age of the fetus from conception, typically 2 weeks less than gestational age.

Q5: How does this relate to trimesters?
A: First trimester = weeks 1-12, second trimester = weeks 13-28, third trimester = week 29 until birth.