Get Virtual Care
For Businesses
About Us
A member asked:
Is first ultrasound or the second more accurate?
A doctor has provided 1 answer
Ultrasound dating: The first. First trimester ultrasound is accurate within 5-7 days. 2nd trimester ultrasound has accuracy of +/_ 2 weeks. Lmp dating also assumes a 28 day cycle. There is no test that can date conception more accurately than a 1 week window. Due date is based on LMP unless us off by more than 1 week 1st trimester or 2 weeks in 2nd.
Answered 2/13/2015
5.1k views
Thank
Related Questions
A member asked:
My first ultrasound showed only a 9mm gest sac. 2 weeks later they could see the baby, measuring 7w1d. How accurate are these measurements for dating?
A doctor has provided 1 answer
A member asked:
What is the range of accuracy for an abdominal ultrasound in the first tri?
A doctor has provided 1 answer
A member asked:
Don't need to pinpoint conception day, but two first trim ultrasound give same due date we have no lmp to go off, how accurate is age of our baby?
A doctor has provided 1 answer
A member asked:
Only possible conception dates: 7/4 and 7/18-23rd my first ultrasound dated me at 13 weeks 5 days.With a conception date of 7/20.How accurate is this?
A doctor has provided 1 answer
People also searched for:
How accurate are early ultrasounds? I had my first ultrasound at 6 weeks and all my other ones have been consistent.
Are conception calculators accurate based off first ultrasound?
How accurate are first trimester ultrasounds done abdominal?
How accurate are first trimester ultrasounds at 8w1d & 9w5d done 2 weeks apart? And how much can it be off by?
Concerned about edd accuracy. Is it possible for ultrasound measurements in the first try to be a month off? All of my edds have matched through preg.
Didn't find what you're looking for?
90,000 U.S. doctors in 147 specialties are here to answer your questions or offer you advice, prescriptions, and more.
Ask your questionMore of what we treat
Content on HealthTap (including answers) should not be used for medical advice, diagnosis, or treatment, and interactions on HealthTap do not create a doctor-patient relationship. Never disregard or delay professional medical advice in person because of anything on HealthTap. Call your doctor or 911 if you think you may have a medical emergency.
HIPAASecure
SOC 2 Type 2Certified
JCAHOAccredited
Download HealthTap
Video visit and message your doctor
