Why Amniocentesis Is Recommended
When a woman has undergone the routine first trimester pregnancy tests and there is some concern regarding the baby's health or development, the doctor may recommend an amniocentesis in order to gain more information on any risk that appears to be developing. The testing is done through a sample of the amniotic fluid, which surrounds the baby in the womb.
Most frequently, this type of testing is done to determine whether the baby has a chromosome abnormality, which may result in Down syndrome, or other associated conditions. There are only two tests that can determine such risks, the chorionic villus sampling (CVS) test, and amniocentesis.
Reason For An Amniocentesis
Commonly done between 16 and 20 weeks gestation, women who opt for this test do so because there is an increased risk for genetic or chromosomal problems in their baby. This test is invasive and carries with it a risk of miscarriage. Amniocentesis is also performed to determine the state of the baby's lungs if an early delivery seems likely-as in the case of premature labor. If a woman's water has broken prematurely, an amniocentesis will show whether there is a uterine infection. The risk of blood incompatibility is also determined through amniocentesis. Sometimes there is an Rh factor sensitization, which can cause problems for both mother and baby if it is not identified, and an amniocentesis can help identify such a situation.
Disorders And Defects Amniocentesis Can Detect
Amniocentesis is very accurate in detection of chromosomal abnormalities such as Down syndrome, trisomy 13 and trisomy 18, sex chromosome abnormalities such as Turner syndrome and Klinefelter syndrome as well. It is also effective in detecting many different genetic disorders, including cystic fibrosis, sickle cell disease, and Tay-Sachs disease. While the test is not used to search for all the various diseases, if there is some concern that the baby is at increased risk for one in particular, then the amniocentesis can be used to determine if the disease is present. It can detect spina bifida and anencephaly, which are neural tube defects. However, it cannot detect birth defects such as cleft palate or heart malformations.
Miscarriage Risk And How To Lessen It
There is a risk for miscarriage following an amniocentesis. However, because a certain percentage of women will miscarry in their second trimester regardless, it is difficult to know if the miscarriage following an amniocentesis was caused by the procedure. Risk depends in large part upon the skill and experience of the medical professional performing the procedure. In order to reduce the risk, a referral to a doctor with a lot of experience is advised. Check the doctor's record in terms of procedure-related miscarriages and if the results are not satisfactory, obtain another referral.
It is also wise to have an experienced ultrasound technician present to guide the procedure through imaging. This reduces the need for a second attempt at obtaining adequate fluid and reduces the risk of injury to the baby by the amniocentesis needle.