There is no conclusive answer. There are different approaches on the subject and each couple should follow their beliefs.

The approach that supports amniocentesis will give significant weight to the following parameters:

• Even though a negative result in amniocentesis does not guarantee that the fetus will not become infected later, the studies of Bilavsky, Pardo and others[1]suggest that even if there is an infection, the fetus is not expected to suffer serious injury. Therefore, in the event of a negative amniocentesis result, some experts will recommend to stop monitoring until the delivery, and some will recommend one targeted scan to be on the safe side, around week 32. On the other hand, a woman who does not undergo amniocentesis is regarded as having an infected fetus, and therefore she will undergo the full protocol of tests until the end of the pregnancy.

• In cases where an amniocentesis was performed, the experts on targeted scans report that it is easier for them to read the findings and diagnose injuries as related to the virus, if such are found. For example, an injury identified in the digestive system can be inconsequential if it is known that the fetus was infected with CMV, but can be of great significance if he was not infected.
  
  

On the other hand, there is also the opposite approach that contends that the amniocentesis is not necessary, since the test is invasive and poses a risk, and only provides information on whether the fetus was infected, and not on whether they were injured as a result of being infected with the virus.

If a woman chooses not to have the amniocentesis, she will undergo the full protocol of tests, and if any finding is discovered, the doctors will consider recommending the amniocentesis at a later date.

The choice of the doctor performing the amniocentesis in the case of CMV is as important as in the case of an amniocentesis without a CMV infection.

Some hospitals will do the test in their own lab; some hospitals do not have a lab, but they will arrange for the test tube to be delivered for you to an appropriate lab; and in some hospitals, the woman’s escort will have to independently deliver the test tube to a virology lab; independent delivery is also required if the amniocentesis is done in the private setting.
For a list of virology labs that test amniotic fluid.

CMV amniocentesis can detect CMV in the urine excreted by the fetus, which helps determine whether the fetus has been infected.

It is preferable to perform the test after week 21 of pregnancy, provided that at least seven weeks have passed since the estimated time of maternal infection. In addition, initial research evidence suggests that if the mother was infected around conception or early in the first trimester, the test sensitivity will also be high when performed at the usual timing of amniocentesis (weeks 17 to 20). Therefore, the doctor may consider performing the test earlier

Between weeks 24 and 32, the test is generally not performed in Israel due to the risk of preterm birth caused by the procedure. Preterm delivery at such an early gestational age carries significant risks unrelated to CMV.

If the couple does not wish to perform amniocentesis for CMV, it is recommended to follow the same protocol used for a positive amniocentesis result and conduct imaging based monitoring. The physician may consider performing amniocentesis later in the pregnancy only if signs of fetal injury appear.

Testing the amniotic fluid for CMV uses the same procedure as a standard genetic amniocentesis, with one difference: an additional vial of amniotic fluid is collected and sent to a virology laboratory.

If the maternal infection occurred after week 16 and because the risk of fetal injury from such an infection is low, the doctor may choose imaging follow up only.

Women who undergo amniocentesis at week 32 will be asked to receive two injections to promote fetal lung maturation a few days beforehand. After the procedure, the woman will remain under observation and be connected to a fetal monitor for about thirty minutes. In addition, the procedure must be performed in a hospital with delivery facilities, with an additional physician present. This detailed protocol ensures that if any complication arises, the fetus can be treated in the optimal way.

It is important to obtain Form 17 both for the amniocentesis and for the virology laboratory.
The CMV infection test result is usually returned within a few days.

Whenever maternal infection occurs during pregnancy, it is recommended to perform a urine or saliva test for the newborn after birth. Details of these tests can be found in the Birth and Time in the Neonatal Department tab.

If amniocentesis is negative, there is still an approximately eight percent chance of fetal infection. However, since the assumption is that infection occurred after the procedure, meaning during weeks when injury is not expected, recommendations range from the more lenient approach of performing only a newborn saliva or urine test after birth to the more cautious approach of performing one targeted ultrasound scan around weeks 30 to 32.

A list of hospitals where the test can be performed can be found in the Important Telephone Numbers tab

In most hospitals, the standard is not to perform the test between weeks 24-32, due to the risk of premature birth due to the puncture and the birth of a premature infant at an early week, with all of the risks that this entails, regardless of the CMV virus.

Women who undergo the test in week 32 will be asked to have genetic counselling even if they had genetic amniocentesis in an earlier week of the pregnancy.

The women will be asked to receive two injection to mature the fetus’ lungs a few days prior to the amniocentesis.

The test has to be performed at a hospital with delivery rooms and another doctor, in addition to the doctor performing the amniocentesis, must be present in the room.

After the test, the woman will remain for observation and will be connected to a monitor for about half an hour.

This procedure is in place for the event that premature birth develops due to the test.

In the case of a negative amniocentesis, there is still approximately an 8% chance of fetal infection. However, since it is assumed that the infection occurred after the amniocentesis, during weeks when severe damage is no longer expected, recommendations range from the more lenient approach of performing only a saliva/urine test after birth to the more cautious approach of conducting one targeted scan around weeks 30–32