How accurate are dating scans in pregnancy
Announcing: Experts in mesh and bladder sling revisions and removals. Avoid Mosquito Bites: Protect yourself and your family from mosquito bites that can make you sick Centers for Disease Control and Prevention: Zika and Pregnancy Insect Repellent Use and Safety: Which mosquito repellents work best?The accurate determination of a patient's "due" date, referred to by doctors and midwives as the EDC (Estimated Date of Confinement) or EDD (Estimated Date of Delivery), is very important for a variety of reasons.My 12 week scan put me like 9 days ahead of my date using lmp!When I checked against the date of conception it matched up with the scan date.In normal state, each body tissue type, such as liver, spleen or kidney, has a unique echogenicity.Fortunately, gestational sac, yolk sac and embryo are surrounded by hyperechoic (brighter) body tissues.In fact, when a woman who has very regular, "textbook" 28 day cycles presents for prenatal care, this often turns out to be the correct EDC more often than not.Other information used to calculate the gestational age, or the number of weeks and days from the first day of the last menstrual period (LMP), includes the size of the uterus on pelvic bimanual examination.
From what I've heard,most often lmp is used because most don't know the date of conception but lmp is not as accurate.
However, it is extremely common to encounter patients who have irregular or infrequent menstrual cycles, or have fibroid tumors that cause their uterus to feel enlarged on pelvic exam, or who conceive shortly after a pregnancy ends (without ever actually having had a period after the last pregnancy), or who got pregnant while taking birth control pills, and these situations often render the above methods useless and misleading when trying to figure out a reliable EDC.
This is where our wonderful ultrasound machines can make a crucial difference.
Even when you can remember when your last menstrual period began, ultrasound can still be more accurate than relying on your last period date alone.
The American College of Obstetricians and Gynecologists state the following: “Ultrasound measurement of the embryo or fetus in the first trimester (up to and including 13 6/7 weeks gestation) is the most accurate method to establish or confirm gestational age” (Committee Opinion, No. Even though using your last period date (LMP) is a traditional dating method, the accuracy of this practice depends on a regular menstrual cycle of 28 days, with ovulation occurring on the 14th day of the cycle.
Search for how accurate are dating scans in pregnancy:
With today's modern equipment, we can obtain very reliable images and measurements of even very early pregnancies, sometimes even seeing a heartbeat as early as 5-6 weeks!