Genetic Counseling and amniocentesis

Genetic counseling is a very important component of any pregnancy, but not everybody requires the same degree of counseling. Most couples do not have any significant family history of genetic disorders. However, it is important to assess a detailed genetic questionnaire to know if you, the father of the baby, and your respective families, have any conditions for which you can be tested or that place you at risk of having a baby with a genetic disease. We have a copy of just such a questionnaire that may help guide you. If you have questions, please call our office for a consultation. Our Maternal-Fetal Medicine specialists work closely with geneticists to assist you with your concerns.

Who Needs Genetic Counseling?

All pregnant women who will turn 35 years of age at the time of their due date are candidates for genetic counseling. You may have your counseling prior to conception, during the first trimester, or the second trimester up to 24 weeks. It is however advisable to obtain genetic counseling prior to or very early in your pregnancy if you want to avoid late second trimester surprises. Genetic tests are associated with high degree of emotional upheaval when a result confirms the presence of a potentially serious genetic finding. Avoid delays in your care and obtain early counseling and testing as needed.

Each ethnicity is prone to certain genetic conditions, therefore it is important to find out what are the most current available tests for your specific ethnicity. It is financially prohibitive to test for all known genetic disorders, but it is reasonable to test for conditions for which your ethnicity places you at highest risk. Beware that not all laboratories perform exhaustive genetic testing and quality assurance is a must when choosing a laboratory for your genetic tests. Allow us to help you with the choice of tests that are of significance to your ethnicity and with the choice of reliable laboratory facilities.

What are the different types of genetic testing?

Genetic testing may entail blood draws from you, your partner, or a family member affected by a genetic disorder. Genetic testing may also entail evaluation of your current pregnancy by Chorionic Villus Sampling (CVS) or amniocentesis. We do not perform CVS in our office, however should you need that test we will arrange for you to have it at one of the referral centers that we use for such testing.

What is Amniocentesis?

Amniocentesis is an invasive procedure that requires a needle insertion into the amniotic sac (the pregnancy sac) to obtain amniotic fluid (the fluid around the fetus). The procedure is performed through the abdomen under ultrasound guidance of the needle. The procedure is associated with a small degree of pain (the sensation of an injection sometimes followed by the sensation of a cramp in your uterus). The procedure takes approximately one minute to complete.

When can Amniocentesis be performed?

Early amniocentesis can be performed between 12 weeks and 14 weeks 6 days of pregnancy. A small amount of amniotic fluid is drawn from the internal pregnancy sac (the amnion) and sent to a genetic laboratory for testing of cells in the fluid. The cells are evaluated for the normalcy of their chromosomes and can be tested for genetic conditions for which there is a known mutation, such as Cystic Fibrosis or Tay-Sachs. The chromosomes can be evaluated in two methods. One method is optional and allows for quick detection of five chromosomal aneuploidies: Down syndrome, Trisomy 18, Trisomy 13, Turner syndrome, and Kleinfelter syndrome. This quick test called F.I.S.H. requires 48 hours to complete and has a near 99 % accuracy. The second test that can be performed is the standard cell culture that is done on all amniotic fluid submitted for chromosomal testing. This cell culture requires up to 14 days for completion. The length of time to completion is simply dependent on the rate of cell growth in culture and has no bearing on the normalcy of the results.

Risks of Amniocentesis

Early procedure is associated with 1 % risk of pregnancy loss. The cause of the pregnancy loss is usually rupture of the sac at the site of the needle insertion, usually observed within two weeks of the procedure, and its symptoms are those of wetness in the vagina or clear fluid loss from the vagina. Early amniocentesis if performed prior to 12 weeks 4 days has a 3 % risk of clubfeet, an abnormality caused by loss of fluid from the internal pregnancy sac (the amnion) that may occur after the procedure with draping of the sac around the fetal feet interfering with their normal development. The risk of clubfeet from early amniocentesis is not seen past near 13 weeks. Our Maternal-Fetal Medicine specialists are skilled in early amniocentesis, but reserve this invasive test to fetuses with serious ultrasound abnormalities or to fetuses at very high risk of serious genetic conditions.

Standard, or regular amniocentesis is performed between 15 and 20 weeks of pregnancy. The procedure is the same as that described above for early amniocentesis in terms of the technique of performing it and the discomfort associated with it. The amniotic fluid testing is also the same as that of early amniocentesis with optional F.I.S.H. testing and the obligatory cell culture. It is also possible to perform testing on cells obtained by this amniocentesis for known genetic mutations as described above. Standard amniocentesis is associated with 1 in 200 to 1 in 400, pregnancy loss. The cause of pregnancy losses is the same as that of early amniocentesis namely rupture of the pregnancy sac that may occur up to two weeks after the procedure and its symptoms are those of leaking fluid vaginally. Our Maternal-Fetal Medicine specialists are skilled in performing second standard amniocentesis.

Some misconceptions about amniocentesis are that the needle is inserted through the "belly-button". The needle is actually inserted through any part of the lower abdomen that allows safe access to the pregnancy sac. The needle is inserted by ultrasound guidance so as to avoid the fetus and the umbilical cord. The likelihood of direct fetal injury or cord injury is remote with current high-resolution sonography. The rare cases of pregnancy loss do not occur during the procedure, as they are the result of the pregnancy sac failing to heal appropriately after the needle is withdrawn from the sac. The most common cause of pregnancy loss after amniocentesis, is premature rupture of the membranes, i.e. breaking of the pregnancy sac with permanent loss of amniotic fluid around the fetus.

If you wish to have an amniocentesis, we will require the knowledge of your blood type. If you are of a "negative" blood type, you may require an injection of Rhogam after the amniocentesis if the father of the baby is of "positive" blood type. If the father of the baby is of "negative" blood type, you do not require Rhogam. Please note that Rhogam, is frequently not covered by your insurance company and we do not stock it in our office. Your obstetrician at times stocks Rhogam and requests that we send you to their office after the amniocentesis to receive it. At times you will have to go to a local pharmacy to obtain the Rhogam prior to your amniocentesis.

Side effects of Amniocentesis

After the amniocentesis you may experience mild uterine cramps for a few hours. These cramps respond to bed rest, eating, drinking water, emptying your bladder, taking Tylenol extra-strength (2 pills), and rarely, taking Advil (2-3 pills). You are advised to rest for one day after the amniocentesis. You should avoid lifting objects heavier than 10 pounds, and you should not have sex for a week after the procedure. It is common to experience a small amount of clear fluid leaking vaginally, but it should not exceed one or two episodes of a quarter size diameter of fluid noted on your underwear. It is also common to experience one or two small drops of blood vaginally. You should rest until you have none of the aforementioned symptoms and at least for one day after the amniocentesis.

If you should develop heavy vaginal bleeding, similar to a period, or if you should have severe cramps in your lower abdomen, fever and chills, or loss of copious fluid from the vagina, you should contact your Obstetrician and our office immediately and you should go to the emergency room of the hospital you are registered to deliver at.

How to prepare for, and what to expect during, Genetic counseling and amniocentesis in our office: