1. What is Gestation Calculation?

Gestation calculation determines the duration of pregnancy in weeks from the first day of the last menstrual period (LMP) to the current date. This is a standard method used in obstetrics to estimate fetal age and determine expected delivery dates.

2. How Does the Calculator Work?

The calculator uses the gestation formula:

Where:

• \( LMP \) — Last Menstrual Period (first day)
• \( Current Date \) — Today's date or specified date
• \( \left\lfloor \right\rfloor \) — Floor function (rounds down to nearest integer)

Explanation: The calculation finds the difference in days between the current date and LMP, then converts to weeks by dividing by 7 and rounding down to the nearest whole number.

3. Importance of Gestation Calculation

Details: Accurate gestation calculation is essential for monitoring fetal development, scheduling prenatal tests, determining due dates, and making clinical decisions about pregnancy management and delivery timing.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period and the current date (or any date you want to calculate gestation for). 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 it's the standard reference point in obstetrics.

Q2: What is a normal gestation period?
A: A full-term pregnancy is typically 40 weeks (280 days) from LMP, with normal range being 37-42 weeks.

Q3: How accurate is LMP-based gestation?
A: LMP dating is generally accurate within ±2 weeks. Ultrasound measurements in early pregnancy can provide more precise dating if LMP is uncertain.

Q4: What if my cycles are irregular?
A: For women with irregular cycles, LMP dating may be less accurate. Early ultrasound dating is recommended in these cases.

Q5: Why round down to whole weeks?
A: Rounding down to completed weeks is the clinical standard for reporting gestation, as it provides a clear, standardized measurement.