Pregnancy Calculator
Understanding Pregnancy Calculation
Our pregnancy calculator helps estimate your due date and track your pregnancy progress based on different starting points. Here's how it works:
Based on Last Menstrual Period (LMP)
The most common method uses the first day of your last period. Pregnancy typically lasts about 40 weeks from this date. This is known as Naegele's rule.
Based on Due Date
If you already know your estimated due date (from your doctor), we can calculate backwards to determine conception and other important dates.
Based on Conception Date
If you know when conception occurred (within a day or two), we can calculate forward to estimate your due date, which is typically 38 weeks from conception.
Based on Ultrasound
Early ultrasound measurements (especially first trimester) can provide the most accurate due date estimation. We adjust based on the ultrasound date and how many weeks pregnant you were at that time.
Based on IVF Transfer
For IVF pregnancies, we calculate based on the embryo transfer date and whether it was a 3-day or 5-day embryo.
Pregnancy Duration Facts
- Full-term pregnancy is between 37-42 weeks
- Only about 5% of babies are born on their exact due date
- Most births occur within 2 weeks before or after the due date
- First pregnancies often last slightly longer than subsequent ones
When to Consult Your Doctor
While this calculator provides useful estimates, always follow your healthcare provider's recommendations. Contact your doctor if:
- You have concerns about your pregnancy dates
- You experience unusual symptoms
- Your menstrual cycles are irregular
- You have a history of pregnancy complications
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