Due Date Calculator
Due Date Calculator
The Due Date Calculator estimates the delivery date of a pregnant woman based on her last menstrual period (LMP), ultrasound, conception date, or IVF transfer date.
How the Due Date is Estimated
The due date (estimated date of confinement) is an approximate date when a baby is expected to be born. Only a small percentage of babies are born exactly on the due date.
Why It’s an Estimate
- Only about 4% of births occur on the exact due date
- Pregnancy length can vary naturally
- Doctors often consider a range of dates (37–42 weeks)
Methods to Calculate Due Date
1. Last Menstrual Period (LMP)
This is the most common method. Pregnancy is estimated as 40 weeks (280 days) from the first day of the last period.
2. Ultrasound Method
Ultrasound uses fetal growth measurements to estimate gestational age and predict the due date, especially in early pregnancy.
3. Conception Date
If the exact conception date is known, the due date is estimated by adding approximately 38 weeks from conception.
4. IVF Method
For IVF pregnancies, the due date is calculated based on embryo transfer date, making it more precise than natural conception methods.
Pregnancy Timeline
- Preterm: Before 37 weeks
- Early Term: 37–39 weeks
- Full Term: 39–41 weeks
- Late Term: 41–42 weeks
- Post Term: After 42 weeks
Why Due Date Matters
- Helps doctors monitor pregnancy progress
- Useful for planning delivery
- Identifies risks of early or late birth
Frequently Asked Questions (FAQs)
How accurate is a due date?
A due date is an estimate. Most babies are born within 1–2 weeks before or after the due date.
What is the most accurate method to calculate due date?
Early ultrasound is generally the most accurate method for determining due date.
Can due date change?
Yes, doctors may adjust the due date after ultrasound results or medical evaluation.
How long is normal pregnancy?
Normal pregnancy lasts about 37 to 42 weeks.
References
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