PAPPA and fetal growth restriction: This could not be sustained by any of the theories about how the impair trophoblast invasion process is related to a low serum PAPP-A as in other works, where lower levels than the fifth percentile are reported to increase the risk of developing impaired placentation disease: intrauterine growth restriction (adjusted odds ratio, 2.9; 95% confidence interval [CI], 2.0–4.1) and preeclampsia (adjusted odds ratio, 2.3; 95% CI, 1.6–3.3) [17].