Mijal et al found that the serum level of PlGF in preeclampsia pregnant women was significantly decreased by comparing with normal pregnant women.8 Cetin I et al found that PlGF level could be used to predict the risk associated with adverse pregnancy such as very low birthweight infants and emergency childbirth.9 However, our results showed that the level of serum PlGF in preeclampsia group was significantly lower than that in normal pregnancy control group (P < 0.05) and indicated that placental growth factor was a protective factor for preeclampsia. Here, PGF is linked to preeclampsia.