1. What is Pregnancy Calculator Without LMP?

The Pregnancy Calculator Without LMP estimates the due date when the last menstrual period (LMP) is unknown, using ultrasound dating and current date to calculate the estimated due date (EDD).

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Ultrasound Weeks \) — Gestational age from ultrasound (weeks)
• \( Current Date \) — Date of ultrasound or current assessment
• \( EDD \) — Estimated Due Date

Explanation: This calculation adjusts the current date by adding the ultrasound weeks and subtracting the equivalent days to determine the estimated conception date and subsequent due 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 gestational age in weeks from ultrasound examination and the current date. Ultrasound weeks should be between 6-42 weeks for optimal accuracy.

5. Frequently Asked Questions (FAQ)

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

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

Q3: What if I have multiple ultrasounds?
A: Use the earliest ultrasound measurement for the most accurate dating, as fetal growth becomes more variable later in pregnancy.

Q4: Can this calculator be used throughout pregnancy?
A: Yes, but accuracy is best when using first-trimester ultrasound measurements (6-13 weeks).

Q5: What if my calculated EDD differs from my doctor's estimate?
A: Always follow your healthcare provider's recommended due date, as they may have additional clinical information.