1. What is the NHS Baby Due Date Calculator?

The NHS Baby Due Date Calculator estimates your expected delivery date based on the first day of your last menstrual period (LMP). This is the standard method used by the NHS for calculating pregnancy due dates.

2. How Does the Calculator Work?

The calculator uses the standard NHS formula:

Where:

• \( EDD \) — Estimated Due Date
• \( LMP \) — First day of Last Menstrual Period
• \( 280 \text{ days} \) — Standard pregnancy duration (40 weeks)

Explanation: This calculation assumes a regular 28-day menstrual cycle and that conception occurred approximately 14 days after the LMP.

3. Importance of Due Date Calculation

Details: Accurate due date calculation is essential for proper prenatal care, monitoring fetal development, scheduling important tests, and preparing for delivery.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period in the date format. The calculator will provide your estimated due date and current weeks of pregnancy.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the due date calculation?
A: The due date is an estimate - only about 5% of babies are born on their exact due date. Most births occur within 2 weeks before or after the calculated date.

Q2: What if I have irregular periods?
A: If you have irregular cycles, an early ultrasound scan (dating scan) between 8-14 weeks provides a more accurate due date.

Q3: Can the due date change during pregnancy?
A: Yes, your due date may be adjusted after your first ultrasound scan if there's a significant difference from the LMP-based calculation.

Q4: What is considered full term?
A: A pregnancy is considered full term between 37-42 weeks. Babies born before 37 weeks are premature, after 42 weeks are post-term.

Q5: When should I contact my midwife?
A: Contact your GP or midwife as soon as you know you're pregnant to begin your antenatal care.