Home
Back
American Pregnancy Calculation Formula:
| From: | To: |
The American Pregnancy Calculator estimates the due date based on the last menstrual period (LMP) using the standard calculation of LMP + 280 days. This method is recommended by the American Pregnancy Association for estimating the expected delivery date.
The calculator uses the standard pregnancy calculation formula:
Where:
Explanation: This calculation assumes a regular 28-day menstrual cycle and that ovulation occurred on day 14. The 280 days represents 40 weeks of pregnancy from the first day of the last menstrual period.
Details: Accurate due date estimation is crucial for proper prenatal care, monitoring fetal development, planning for delivery, and identifying potential pregnancy complications. It helps healthcare providers track appropriate fetal growth and development milestones.
Tips: Enter the first day of your last menstrual period in the date field. Make sure to use the actual first day of bleeding, not the last day. The calculator will provide your estimated due date and current pregnancy progress.
Q1: How accurate is the LMP method?
A: The LMP method is generally accurate for women with regular 28-day cycles. For women with irregular cycles, an early ultrasound may provide a more accurate due date.
Q2: What if I don't know my LMP?
A: If you're unsure of your LMP, consult with your healthcare provider who may recommend an ultrasound to estimate gestational age and due date.
Q3: Why 280 days instead of 9 months?
A: Pregnancy is calculated as 40 weeks from LMP, which equals 280 days. This differs from calendar months due to varying month lengths.
Q4: Can my due date change?
A: Yes, healthcare providers may adjust your due date based on ultrasound measurements, especially if there's a significant difference from the LMP calculation.
Q5: What percentage of babies are born on their due date?
A: Only about 5% of babies are born exactly on their due date. Most births occur within two weeks before or after the estimated due date.