1. What is Due Date by Ultrasound?

The due date by ultrasound calculation estimates the expected delivery date based on ultrasound measurements and the remaining days of pregnancy. This method is often more accurate than last menstrual period dating, especially when performed in the first trimester.

2. How Does the Calculator Work?

The calculator uses the simple formula:

Where:

• Ultrasound Date — The date when the ultrasound was performed
• Remaining Days — The number of days remaining until estimated delivery date as determined by ultrasound measurements

Explanation: The ultrasound provides an estimated gestational age which is then used to calculate the remaining time until the due date.

3. Importance of Accurate Due Date

Details: An accurate due date is crucial for proper prenatal care, timing of tests, and decision-making regarding post-term pregnancies. Ultrasound dating is particularly important when menstrual dates are uncertain or when there's a discrepancy between menstrual dating and ultrasound findings.

4. Using the Calculator

Tips: Enter the date of the ultrasound and the number of remaining days until the estimated due date as provided by your healthcare provider. The remaining days are typically calculated based on ultrasound measurements of the fetus.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is ultrasound for dating pregnancy?
A: First trimester ultrasound is most accurate (±5-7 days). Accuracy decreases as pregnancy progresses (±1-2 weeks in second trimester, ±2-3 weeks in third trimester).

Q2: What if my ultrasound due date differs from my LMP due date?
A: Healthcare providers typically use the ultrasound date if there's more than a certain difference (often 5-7 days in first trimester, 10-14 days later).

Q3: Can the due date change after an ultrasound?
A: Yes, especially if early ultrasound findings differ significantly from dates calculated by last menstrual period.

Q4: What is the most common ultrasound measurement used for dating?
A: Crown-rump length (CRL) in first trimester, head circumference (HC) and biparietal diameter (BPD) in second trimester.

Q5: Does this calculator account for leap years?
A: Yes, the date calculation automatically accounts for leap years and varying month lengths.