Because the peripheral resistance of the placenta is high and the development of the fetal lymphatic system is immature during weeks 10 through 14 of gestation, nuchal edema is most evident at this time (Berger, 1999). After the 14th week of gestation, the fetal lymphatic system becomes more developed and can compensate for the excess fluid in the nuchal area. Therefore, the FNT screen is not as reliable after the 14th week of gestation. Because fetal abnormalities cannot be diagnosed using ENT, this test is used to screen the population to identify pregnancies in need of diagnostic testing. If the FNT measurement falls within the normal range, the woman continues to receive typical prenatal care. If the FNT measurement exceeds the limit of the normal range, diagnostic genetic testing is indicated.