Ultrasound for Size and Dates: Dating based on your last menstrual period can be very inaccurate. Ultrasound done early in the first trimester allows for accurate dating of the pregnancy. Since the fetus (baby) is extremely small, it also allows for better visualization of maternal structures (uterus, ovaries, and fallopian tubes), and gives us the ability to detect any abnormalities very early. However, if this ultrasound is performed too early (before 7 weeks gestation), the fetus may not be developed enough to get all of the information needed and you may be asked to return in 1-2 weeks.
Nuchal Translucency (NT): The NT is a non-invasive screening ultrasound that is used in the 1st trimester to detect Down syndrome, trisomy 18, or other problems. The results of the nuchal translucency screening are then combined with those of 2 blood tests and the mother's age to assess the risk for the fetus. Since there is only a very short window to obtain the necessary measurements, it is extremely important that we have accurately dated the pregnancy with a size/dates ultrasound first.
Sequential Screening, 1st Trimester (Blood test drawn with NT scan): This is a 2 part test. First trimester screening tests include blood tests and an ultrasound exam (NT). Sequential screening is used to determine the risk of Down syndrome, trisomy 18, and open neural tube defects. The timing of genetic screening tests is important because levels of the substances measured change throughout the pregnancy.
Sequential Screening, Second Trimester: The second part of Sequential Screening. Once you have completed the first blood test, you will receive a call from our office with dates for you to return to the lab to get this test done. For the most accurate results, it is very important that you have your blood drawn during the optimal time frame.
Level 2 Ultrasound: Used to screen for malformations and appropriate fetal growth. This ultrasound provides very detailed measurements of the fetus. This is also a great opportunity for you to get some great pictures of your new baby!
Your doctor may order an ultrasound to assess fetal growth and well-being, check for position, cervical length, and many other reasons. If you have questions please ask your doctor why an ultrasound was ordered.