Objective:Chromosomal disorders are cause of the most part of neonatal death and adverse effect of pregnancy the aim of this study was to compare adverse effect of pregnancy between first and second trimester abnormal aneuploidy screen test who referred to shahid- beheshti hospital of babol at 2013-2014. Methods : We design a longitudinal prospective cohort study Patients: we evaluated all of pregnant women who referred to shahid- beheshti hospital of babol from july 12 to 15 december. Intervention and Main Outcome Measure: Patient data included: demographic و Past Medical history و screening test result (B-hcg و PAPP-A و MSAFP و unconjugated estradiol- Inhibin-A and NT) were recorded. Data was analysed by SPSS 18. Result:486 pregnant women participated in this study. The mean age and BMI were 28-21± 4/58 years and 26/25±3/95 kg/m²Respectively. Abnormal test was observed in 17 potient (3/5%). the adverse effect of pregnancy was observed in 44 patients(9/1%) there was no significant difference between the mean age of pregnant women with and without of preeclampsia in patient with abnormal screen test was 24/14 time of other pregnant women(RR 24/14 و 95% CI و 9/89-58/87 p<0/0001)Howwever. no relationship was observed bethween Abnormal screen test with LOW and RROM. The risk of pregnancy adverse effect in patients with abnormal screening test was 6/13 times more than other pregnant women (RR=6/13 95% CI 3/38-11-10 P<0/0001) the risk of preeclampsia was 29/87 times inpatient with abnormal level of inhibin-A (RR=29/78 95% CI 13/22 67/49 و P<0/000( Conclusion: the risk of preeclampsia with higher in pregnant women with abnormal screening test. However no.