Pregnancy Calculator NHS

NHS Pregnancy Due Date Formula:

\[ EDD = LMP + 280 \ days \]

Estimated Due Date (EDD):

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1. What is the NHS Pregnancy Calculator?

The NHS Pregnancy Calculator estimates your due date based on the first day of your last menstrual period (LMP). This follows the standard NHS method for calculating pregnancy due dates, adding 280 days (40 weeks) to your LMP date.

2. How Does the Calculator Work?

The calculator uses the standard NHS pregnancy due date formula:

\[ EDD = LMP + 280 \ days \]

Where:

\( EDD \) — Estimated Due Date
\( LMP \) — First day of Last Menstrual Period
\( 280 \ days \) — 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. The result gives you an estimated due date for your baby.

3. Importance of Due Date Calculation

Details: Knowing your estimated due date helps healthcare providers monitor your pregnancy progress, schedule important tests and scans at the right times, and prepare for your baby's arrival. It also helps track fetal development milestones.

4. Using the Calculator

Tips: Enter the first day of your last menstrual period in the date field. Make sure to use the correct date format. The calculator will provide your estimated due date and current pregnancy week.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is the NHS due date calculation?
A: The calculation is accurate for women with regular 28-day cycles. Only about 5% of babies are born exactly on their due date, with most arriving within two weeks before or after.

Q2: What if my cycle is longer or shorter than 28 days?
A: If your cycle is regular but not 28 days, your midwife may adjust your due date based on your cycle length. An early dating scan can provide a more accurate due date.

Q3: When should I contact my GP or midwife?
A: Contact your healthcare provider as soon as you know you're pregnant to begin your antenatal care. They will confirm your due date and schedule your appointments.

Q4: Can the due date change during pregnancy?
A: Yes, your due date may be adjusted after your dating scan (usually between 8-14 weeks) if the ultrasound measurements differ significantly from your 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 premature, while those born after 42 weeks are post-term.