What will ultrasound tell me?
Depending on the gestational age of your pregnancy, prenatal ultrasound will provide you and your doctors or midwives with information about various aspects of your developing baby and your pregnancy.
In the first trimester ultrasound confirms viability, determines the gestational age and due date, provides a basic assessment of the fetal anatomy and can be used for targeted views of specific areas such as the nuchal translucency (back of the fetal neck). Measuring the nuchal translucency is useful in assessing the likelihood of certain chromosome abnormalities.
In the second trimester ultrasound can be used to provide more information about your baby’s growth and development. A detailed anatomy survey by ultrasound at about 20 weeks (counting from the first day of the last period) that is interpreted by a perinatologist is one of the best ways to assess your baby’s prenatal development. If a problem is found, your obstetrician or midwife will be called and with their in-put, you will be offered immediate consultation with our perinatologist. Through this consultation, other services such as genetic counseling, amniocentesis, chorionic villus sampling, further ultrasound, and special planning for the baby's birth are made available to parents with a high-risk pregnancy.
What is First Trimester Screening?
First Trimester Screening (Ultra-Screen) includes ultrasound measurement of the nuchal translucency with a maternal blood test for pregnancy associated plasma protein-A and free Beta human chorionic gonadotropin. About 90% of babies with Down syndrome and Trisomy 18 will have a high-risk result. Other chromosome abnormalities may also cause a high-risk result. A low risk result does not eliminate the possibility that the baby may have Down syndrome, Trisomy 18, other chromosome problems, birth defects or mental retardation. Most parents learn that they are at low risk for Down syndrome and Trisomy 18 and appreciate receiving this reassurance. Parents with high risk results are offered genetic counseling and further testing to determine if there baby has a chromosome abnormality or not. Tests such as chorionic villus sampling (CVS) and amniocentesis are performed by board certified perinatologists at Capital Health. For more information on screenings, visit NTD Labs.
What is Chorionic Villus Sampling?
CVS is a placental biopsy performed at 11 – 13 weeks to assess the fetal chromosomes as early as possible in pregnancy. CVS can also be used to check for specific genetic disorders when there is a family history or parents are known to carry certain genes. For more information visit the March of Dimes website and type CVS in the search box.
What is Amniocentesis?
Amniocentesis is performed at 16 – 21 weeks to assess the fetal chromosomes and check the level of alpha-fetoprotein. It can also be used to check for specific genetic disorders when there is a family history or parents are known to carry certain genes. For more information visit the March of Dimes website and type amniocentesis in the search box.
How are the weeks of gestation mentioned above calculated?
The length of pregnancy is typically about 40 weeks counting from the first day of the last menstrual period (LMP). Gestational age as determined by ultrasound measurements is based on this same system. So, if by LMP your pregnancy is 10 weeks, most likely the fetus will measure 10 weeks or so by ultrasound. Since not everyone has 28 day cycles, and conception can occur earlier or later than average within a given cycle, ultrasound in the first trimester is usually the most accurate way to determine gestational age.
What if my amniocentesis or CVS shows that my unborn baby has Down syndrome or some other problem?
If you receive abnormal test results, you will have choices that include continuing your pregnancy and preparing for the birth of your handicapped child, and interrupting your pregnancy.
No one wants to think that their pregnancy will end in sadness, but unfortunately this is a reality for some parents. Hanover Hospital is here for you in times of trouble. Patients experiencing a pregnancy loss or the death of a baby are cared for by nurses, doctors, genetic counselors and ultrasound technicians experienced not only in providing the best medical care, but also in addressing the emotional needs of parents and families during such difficult times. Hanover Hospital also offers support for perinatal bereavement.