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NHS Pregnancy Due Date Formula:
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The NHS Due Date Pregnancy Calculator estimates the expected delivery date based on the last menstrual period (LMP) using the standard formula of LMP + 280 days. This method is widely used in clinical practice for pregnancy dating.
The calculator uses the NHS standard formula:
Where:
Explanation: This calculation assumes a regular 28-day menstrual cycle and ovulation occurring on day 14. The due date represents the estimated date of delivery (EDD).
Details: Accurate due date calculation is essential for proper prenatal care, monitoring fetal development, scheduling tests, and planning for delivery. It helps healthcare providers track pregnancy progress and identify potential complications.
Tips: Enter the first day of your last menstrual period. Ensure the date is accurate for the most reliable estimation. The calculator will provide the estimated due date based on the standard 280-day pregnancy duration.
Q1: How accurate is the LMP method?
A: The LMP method is reasonably accurate for women with regular cycles. However, early ultrasound dating is often more precise, especially if cycle length varies.
Q2: What if my cycle is longer than 28 days?
A: For cycles longer than 28 days, the due date may need adjustment. Typically, add the number of days over 28 to the calculated due date.
Q3: Can the due date change during pregnancy?
A: Yes, healthcare providers may adjust the due date based on early ultrasound measurements, which are often more accurate than LMP dating.
Q4: 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 date.
Q5: When should I contact my healthcare provider?
A: Contact your healthcare provider as soon as you suspect pregnancy to begin prenatal care and confirm your due date through clinical assessment.