Fetal fibronectin is a protein which plays a vital role in pregnancy. This protein, which is produced by fetal cells, serves to bind together the fetal membrane and the lining of the uterus. The protein is also a useful diagnostic marker for premature delivery, as the fetal fibronectin test can effectively determine whether or not a woman is likely to carry her pregnancy to term.
Fibronectin is a type of protein which is important in several cellular processes, including cell growth and adhesion. The process of cell adhesion describes how certain types of cells “stick” to other types of cells or tissues. This property of this protein is what makes the protein important in fetal development. Fetal fibronectin is produced in the uterus and helps the chorion, the fetal membrane, and the decidua, the lining of the uterus, adhere together. This enables the fetus to be held securely inside the uterus.
Fibronectin produced by fetal cells can be detected in the vagina at certain stages of pregnancy. Up until 22 weeks it is possible to detect fibronectin in the vagina. After this point, fibronection levels in the vagina begin to decrease. By 24 weeks, fibronectin is not present in the vagina during a healthy pregnancy, and levels of the protein do not begin to increase again until the week 34. This pattern of fibronectin secretion makes the fetal fibronectin test an accurate way of determining whether a woman is at risk of premature childbirth.
As a woman nears the end of her pregnancy, the fibronectin inside the uterus begins to break down, as part of the body’s preparation for childbirth. When this happens, fibronectin can be detected in the vagina. In a typical pregnancy this happens at or after 34 weeks; if a woman is at risk of premature birth, fibronectin may be detected in the vagina before the 34-week mark.
One important thing to note is that a positive fetal fibronectin test does not necessarily mean that a woman will give birth prematurely. It is simply a measure of risk: women who test positive are at increased risk of premature delivery. Even so, the test is useful because it allows the woman, her family, and her healthcare providers to prepare for the possibility.
Another useful aspect of the test is that it can help predict whether a woman with symptoms of premature labor is really at risk of delivering her child early. This is important because many women with such symptoms go on to carry their pregnancies to term. The fibronectin test helps differentiate between women whose symptoms indicate a high level of risk, and women whose symptoms indicate a low level of risk, and is the only way to differentiate between these two categories.