Maternal fetal flowmetry: everything you need to know about Doppler during pregnancy
Maternal-fetal flowmetry is an ultrasound-based examination (also called Doppler) that allows you to monitor blood flow in the arteries and the proper functioning of the placenta during pregnancy. This is not a routine examination, but is carried out only in special cases such as failure of the fetus to grow. Let's find out together what it consists of and when it is necessary to do it. Meanwhile, here is a video to understand how the fetus grows in pregnancy:
What is flowmetry?
Flowmetry, as we have anticipated, is an examination that uses ultrasound, just like any obstetric ultrasound. These ultrasounds are able to monitor the blood flow in the arteries without any risk to the pregnant woman and her future baby.
The Doppler is requested by the gynecologist only in particular cases: it is not in fact an examination to be carried out routinely during each pregnancy, but only if there are some complications such as gestational diabetes or preeclampsia, or a failure of the fetus to grow.
The flowmetry, in fact, is very important in case of delay in fetal growth because it allows the doctor to evaluate the health of the child: the Doopler, in fact, detects and provides fundamental data about the circulation of blood in the arteries and therefore about the " oxygenation and functioning of the placenta, the organ that allows the transfer of the same oxygen and nutrients from mother to fetus.
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How does flowmetry work?
Flowmetry works in a similar way to obstetric ultrasound and uses the same technical instrumentation. Through ultrasound it is possible to concentrate the analysis on a particular blood vessel in order to evaluate the speed and quantity of blood flow.
The vessels that are checked are first of all the uterine arteries, ie those that carry blood (and therefore oxygen) from the maternal uterus to the placenta (and therefore to the baby); the umbilical arteries, which carry blood from the fetus to the placenta via the umbilical cord; the middle cerebral artery of the fetus; the venous duct that carries blood from the placenta to the baby's heart.
According to the arteries that are examined, there are two different types of flowmetry, the maternal and the fetal one. Maternal flowmetry is used to assess blood flow in the uterine arteries and is prescribed for pregnant women who have particular health problems and may have complications. It is usually done between the 17th and 23rd week of pregnancy. The fetal flowmetry, on the other hand, is that which analyzes the umbilical arteries, the middle cerebral artery and the venous duct. It is performed from the 32nd week of pregnancy onwards.
After identifying the blood vessel to be monitored, the device sends a Doppler signal that allows you to analyze the characteristics of the artery in question, detecting any problems or complications. The instrument used by doctors allows to obtain the desired results more easily through a coloring effect that helps to visualize the specific vessels sought (it is the so-called "color Doppler").
When should maternal-fetal flowmetry be performed?
Flowmetry should always be performed in the case of fetal growth restriction, i.e. when the fetus has a delay in growth and is not of the size it should be at that precise moment of pregnancy. The Doppler allows in this case to understand the causes of the restriction, if the problem is in the non-functioning of the placenta or if it is necessary to look for it elsewhere.
Flowmetry is also prescribed in case of fetal diseases or malformations, from fetal anemia to possible heart malformations. Finally, it can be of great help to women who suffer from preeclampsia or who are at risk for preeclampsia.
