This week (on the ultrasound examination) you can see how the baby moves its eyes. The eyes are shifted to the center (first they were located on the sides), the ears are approaching to their final position. The legs lengthened and became proportionally in relation to the body. The fingernails are already fully formed. The weight of the child is about 130 g, and the length about 12 cm – the size of a small banana. The uterus weighs approximately 250 grams at this period.
For a period of 16-18 weeks of pregnancy it is recommended pass the triple test – the second screening for the risk of fetal pathology assessment. During the triple test the levels in the blood of alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG) and estriol (E3) are determined.
AFP – a protein that is synthesized by the liver of the fetus. Variations in the level of AFP may indicate for defects of the neural tube, abdominal wall of the fetus, esophageal atresia and 12 finger intestine, as well as some anomalies of the kidney and urinary tract, Turner’s syndrome, the lag of the fetal development.
HCG – hormone released by the placenta throughout pregnancy. High levels of hCG in a pair of low-AFP is characteristic for Down syndrome.
Estriol is also produced by the fetal organs and the placenta throughout pregnancy. The estriol levels in the blood allow us to estimate not only the state of the placenta but the fetus as well.
In case of deviations in the triple test indicators please refer to genetics.