The home pregnancy test was only the beginning. Find out the exams you should consider once you learn you’re expecting.
That home pregnancy test you just took to give you your happy news works by detecting levels of a hormone called human chorionic gonadotropin (hCG), produced by the developing placenta. The test tells you what you need to know: you’re pregnant! But once that’s established, you and your doctors are going to want to know more—much more. An arsenal of medical tests can help monitor your developing pregnancy right from the beginning.
For starters, your doctor might want to do one or more blood tests to determine not only that hCG is present, but how much of it is present. That will help establish that the pregnancy is progressing appropriately. Your doctor will most likely want to check levels of progesterone, too, since adequate levels of this hormone (produced in the ovaries) are also needed to maintain a healthy pregnancy. If tests show that your progesterone level is low or your hCG is not rising appropriately, it could mean an ectopic pregnancy (located in the fallopian tube rather than the uterus) or an impending miscarriage.
Searching For a Heartbeat
At approximately five weeks from your last menstrual period, your doctor might recommend the next test: an ultrasound image. An ultrasound probe inserted into the vagina can produce images of the developing embryo, even at this very early stage. The procedure is also considered perfectly safe. By six weeks a viable embryo with an identifiable heartbeat can be observed this way in more than half of all pregnant women. If no heartbeat can be seen at this time, the test should be repeated a week later. Many embryos don’t show cardiac activity until a bit later than six weeks.
Testing Your Genes
Your family background—yours and your partner’s—helps determine the kinds of genetic tests you should consider. African-Americans, for example, should be tested for sickle cell anemia; 1 in 10 will carry the gene for this disease. Individuals of Ashkenazi Jewish descent are at risk for a host of genetic disorders, including Tay-Sachs, Canavan, Gaucher, and familial dysautonomia, among others. People of Southeast Asian and Mediterranean ancestry should be screened for alpha and beta thalassemias. And testing for cystic fibrosis should be considered by all expectant couples. This gene can occur in families of any racial background, but is the most common lethal genetic disorder in Caucasians. Many medical geneticists also believe that all pregnant women should be offered screening for Fragile X syndrome, the most common inherited form of mental retardation.
Within the past decade, first trimester screening has been developed for chromosome abnormalities like Down syndrome. This early screening involves using a combination of maternal age, ultrasound measurement of fluid accumulation at the back of the fetal neck (nuchal translucency), and biochemical analysis of maternal blood. It is performed between 11 and 14 weeks’ gestation. Unlike a diagnostic test, which provides definitive information about whether a chromosome abnormality is present, a screening test can indicate only a high or low risk. The early screening for Down syndrome will identify 5 percent of the population as high risk. Anyone found to be high risk may proceed to diagnostic testing, such as chorionic villus sampling (CVS, which can be performed late in the first trimester, at 10 to 13 weeks) or amniocentesis (usually an early second trimester procedure, 15 to 18 weeks). The risk of miscarriage from a CVS procedure is estimated as 1 in 100, so if you are considering this procedure make sure you go to a very experienced physician. In the majority of cases, the diagnostic tests will be able to reassure women that they are carrying chromosomally normal children.
Along with the excitement a woman feels when she learns she’s conceived, there may be fear and anxiety about the health of the developing baby. Medical testing can help alleviate these feelings. By following hCG and progesterone levels in early pregnancy to make sure they are rising appropriately, seeing a heartbeat on vaginal probe ultrasound at 6-7 weeks gestation, and checking for specific genetic disorders you may be at risk for, you can improve the chances of delivering a healthy baby, and ease your mind that your pregnancy is progressing normally.
This article was originally published in the Fall 2005 issue of Conceive Magazine.
Related Topics: Pregnancy; Pregnancy Health