1. What is Perinatal Gestational Age?

Perinatal gestational age is the duration of pregnancy calculated from the first day of the last menstrual period (LMP). It is a crucial measurement in obstetrics for monitoring fetal development and determining expected delivery date.

2. How Does the Calculator Work?

The calculator uses the standard gestation calculation formula:

Where:

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

Explanation: The calculation determines the number of complete weeks that have passed since the last menstrual period began.

3. Importance of Gestational Age Calculation

Details: Accurate gestational age calculation is essential for proper prenatal care, fetal growth monitoring, timing of screenings and tests, and determining the estimated date of delivery.

4. Using the Calculator

Tips: Enter the current date and the first day of your last menstrual period. The calculator will automatically compute the gestation in completed weeks.

5. Frequently Asked Questions (FAQ)

Q1: Why use LMP instead of conception date?
A: LMP is used because it's typically more reliably known than the actual conception date and provides a standardized reference point.

Q2: What if my cycles are irregular?
A: For women with irregular cycles, ultrasound dating in early pregnancy may provide a more accurate gestational age assessment.

Q3: How accurate is LMP dating?
A: LMP dating is generally accurate within ±2 weeks when confirmed by first-trimester ultrasound.

Q4: What is considered full term?
A: Full term is typically 37-42 weeks gestation. Delivery before 37 weeks is considered preterm.

Q5: Can this calculator predict my due date?
A: Yes, adding 40 weeks to your LMP gives your estimated due date (Naegele's rule).