Mid-trimester maternal serum AFP and hCG have been associated with adverse pregnancy outcomes in the absence of aneuploidy or neural tube defects. Mid-trimester maternal serum AFP levels > 2.5 MoM are thought to reflect a defect in placentation and are associated with an increased risk of complications in later pregnancy including: late fetal loss, gestational hypertension, preeclampsia, IUGR, preterm delivery and IUFD. Mid-trimester maternal serum hCG > 2.5 MoM is associated with an increased risk of complications in later pregnancy including: late fetal loss, gestational hypertension, preeclampsia, IUGR, preterm delivery and IUFD. Combined mid-trimester elevation in maternal serum AFP and hCG levels suggest a more complex type of placental pathology. They are more strongly associated with complications in later pregnancy including: late fetal loss, gestational hypertension, preeclampsia, IUGR, preterm delivery and IUFD. Mid-trimester maternal serum AFP and/or hCG levels alone cannot detect all pregnant women with increased risk of developing pregnancy complications. Multiparameter testing of placental function in mid-trimester (maternal serum AFP and hCG screening, uterine artery Doppler and placental morphology) may allow us to identify women with increased risk of developing severe placental insufficiency and pregnancy complications.