Purpose of Investigation: The aim of this study is to evaluate whether first trimester maternal serum follistatin like 3 (FSTL3) levels can be used to predict preeclampsia and related obstetric complications. Materials and Methods: The serum levels of FSTL3, pregnancy associated plasma protein A (PAPP-A), and free β-hCG were determined in the first trimester from a sample of 180 pregnant women. All patients had first- and second-trimester ultrasound evaluations. The pregnancy outcome was defined as ‘adverse’ if one of the following outcomes were observed: fetal death, preeclampsia, pregnancy-induced hypertension (PIH), delivery of a small infant for gestational age (SGA) or preterm delivery. Results: FSTL3 levels were not significantly different for preeclampsia and related adverse obstetric outcomes compared to the control group (p < 0.05). Only PAPP-A MoM values were lower in the adverse obstetric outcome group than in the control (p = 0.040). There was no significant association among FSTL3 levels and the presence of any complications, according to our ROC curve analyses (p = 0.846). Conclusions: First trimester FSTL3 levels are not predictive for preeclampsia or adverse pregnancy outcomes.