1. What is EDD Without LMP Calculator?

The EDD (Estimated Due Date) Without LMP calculator estimates the due date of pregnancy when the last menstrual period date is unknown. It uses ultrasound dating to calculate the expected delivery date based on gestational age.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Ultrasound Date \) — Date when ultrasound was performed
• \( Ultrasound Weeks \) — Gestational age in weeks from ultrasound
• \( 40 \) — Standard full-term pregnancy duration in weeks
• \( 7 \) — Days per week conversion factor

Explanation: The formula calculates how many weeks remain until the full 40-week term and converts this to days, which are then added to the ultrasound date.

3. Importance of EDD Calculation

Details: Accurate due date estimation is crucial for prenatal care planning, monitoring fetal development, scheduling important tests, and preparing for delivery.

4. Using the Calculator

Tips: Enter the exact ultrasound date and the gestational age in weeks as determined by the ultrasound. Ensure ultrasound weeks are between 0 and 40 weeks.

5. Frequently Asked Questions (FAQ)

Q1: Why use ultrasound dating instead of LMP?
A: Ultrasound dating is more accurate, especially when LMP is unknown, irregular, or when conception timing is uncertain.

Q2: How accurate is ultrasound dating?
A: First-trimester ultrasounds are most accurate (±5-7 days), while second-trimester ultrasounds are accurate within ±10-14 days.

Q3: What if I have multiple ultrasounds?
A: Use the earliest reliable ultrasound measurement, as early pregnancy dating is most accurate for establishing the due date.

Q4: Can the due date change?
A: Yes, healthcare providers may adjust the due date based on subsequent ultrasounds or clinical findings.

Q5: Is 40 weeks always the standard?
A: While 40 weeks is standard, full-term pregnancy is considered 37-42 weeks. Some calculators may use 280 days from conception.