Fetal-maternal erythrocyte distribution blood test

What is Fetal-Maternal Erythrocyte Distribution (FMDD) Test?

A Fetal-Maternal Erythrocyte Distribution (FMDD) test is an important prenatal blood test performed to screen for chromosome-related disorders in a developing baby. It is a test administered to pregnant women in the second trimester of pregnancy (between 16-20 weeks of pregnancy) to determine the prevalence of chromosomal differences or errors in the baby.


Before undergoing the FMDD test, it is important that the mother thoroughly understand the purpose and procedure of the test. It is very important to discuss any questions that may arise with the medical provider in order to better understand the purpose and effects of the test.


The FMDD test is performed in a hospital or clinic, and involves taking a sample of the mother's blood and the baby's. The procedure is simple and noninvasive, and it does not involve any type of tissue sampling or amniocentesis. The mother's blood is drawn from a vein in her arm, and the baby's blood is obtained by either drawing it from the umbilical cord or taking a sample from the amniotic fluid.

Types of Fetal-Maternal ERythrocyte Distribution Tests

  • Standard FMDD Test – This test is considered most reliable, but cannot detect all genetic conditions.
  • Comprehensive FMDD Test – This test is used to detect more conditions, and is more accurate than the Standard FMDD.
  • FMDD Plus Test – This test is used to detect a wider range of conditions, including those in the fetus and mother.
  • Triple Screen Test – This is a combination of three different tests to help detect more genetic conditions; however, this test is not as reliable as the Standard FMDD.


Generally, the FMDD test is considered to be a safe and reliable procedure. There are no serious risks associated with the procedure, and it has low risks of complications. The procedure also does not place any risk to the baby nor does it cause any harm to the mother.

Why is Fetal-Maternal ERythrocyte Distribution Done?

FMDD tests are used to evaluate the baby's health and for the early detection of chromosomal disorders. The test helps in identifying any chromosomal abnormalities present in the baby before birth. Chromosomal abnormalities can lead to serious conditions, such as Down syndrome and other syndromes.

When is the Fetal-Maternal ERythrocyte Distribution Done?

The FMDD test is typically administered in the second trimester of pregnancy (between 16-20 weeks of pregnancy) as it is considered to be the most accurate during this time. The test is performed at a hospital or clinic, and the results should be available in 1-2 weeks.