1. What is Gestational Age?

Gestational age is a measure of the age of a pregnancy from the first day of the last menstrual period (LMP). It is typically expressed in weeks and days. This is the standard way of measuring pregnancy duration in clinical settings.

2. How is Gestational Age Calculated?

The gestational age is calculated using the formula:

Where:

• Current Date — Today's date or date of assessment
• LMP — First day of the last menstrual period
• 7 — Number of days in a week

Explanation: The calculation counts the number of days between the LMP and current date, then converts this to weeks by dividing by 7.

3. Importance of Gestational Age

Details: Accurate gestational age determination is crucial for proper prenatal care, timing of tests, monitoring fetal growth, and determining the due date (estimated date of delivery).

4. Using the Calculator

Tips: Enter the first day of the last menstrual period and the current date (defaults to today). The calculator will compute the gestational age in weeks.

5. Frequently Asked Questions (FAQ)

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

Q2: How accurate is this calculation?
A: This assumes a regular 28-day cycle with ovulation on day 14. Variations in cycle length may affect accuracy.

Q3: What's the difference between gestational age and fetal age?
A: Fetal age (conceptual age) is about 2 weeks less than gestational age, as it counts from conception rather than LMP.

Q4: When is gestational age most accurate?
A: Most accurate when calculated early in pregnancy (first trimester). Later adjustments may be needed based on ultrasound findings.

Q5: How does this relate to due date calculation?
A: The due date is typically calculated as LMP + 280 days (40 weeks), known as Naegele's rule.