I received the results from my quad screen today. The quad screen measures the levels of four substances in my blood: alpha-fetoprotein, a protein that is produced by the fetus; human chorionic gonadotropin, a hormone produced within the placenta; Estriol, an estrogen produced by both the fetus and the placenta; and Inhibin-A, a protein produced by the placenta and ovaries. The quad screen detects about 75-85% of neural tube defects and 75-80% of Down Syndrome cases; when the blood test is combined with an ultrasound like one we just had, most birth defects can be detected.
The levels of those four proteins are compared to "normal" levels. The "normal" level is really a range based on maternal age and the gestational age of the fetus.
All four markers were well within the normal range. This means our baby is significantly less likely to have Down Syndrome and neural tube defects like spina bifida.