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NHS UK Due Date Formula:
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The Pregnancy Due Date Calculator uses the NHS UK formula to estimate your expected delivery date based on your last menstrual period. This calculation follows the standard method used by healthcare professionals in the United Kingdom.
The calculator uses the NHS UK due date 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 when your baby is likely to be born.
Details: Accurate due date calculation is essential for proper prenatal care, monitoring fetal development, scheduling important tests and scans, and preparing for delivery. It helps healthcare providers track pregnancy progress and identify any potential issues.
Tips: Enter the first day of your last menstrual period (LMP) in the date field. Make sure to use the correct date format and select the accurate first day of your last period for the most reliable result.
Q1: How Accurate Is The Due Date Calculation?
A: The due date is an estimate - only about 5% of babies are born exactly on their due date. Most births occur within two weeks before or after the estimated date.
Q2: What If I Have Irregular Periods?
A: If you have irregular menstrual cycles, an early pregnancy ultrasound (dating scan) between 8-14 weeks provides a more accurate due date estimation.
Q3: When Should I Contact My Midwife Or Doctor?
A: Contact your healthcare provider as soon as you suspect you're pregnant to begin prenatal care and confirm your due date through clinical assessment.
Q4: Can The Due Date Change?
A: Yes, your due date may be adjusted after an early ultrasound scan if there's a significant difference from the LMP-based calculation.
Q5: What Is Considered Full Term Pregnancy?
A: A pregnancy is considered full term between 37-42 weeks. Babies born before 37 weeks are preterm, and those born after 42 weeks are post-term.