
Introduction: Preeclampsia incidence ranges from 1: 1000 to 1: 1700, and 50,000 mothers died of preeclampsia and eclampsia (MOH 2005). Increasing excessive weight gain during pregnancy is one of the factors thought to increase the incidence of preeclampsia. Objective: The purpose of this study was to determine the effect of Excess weight gain during pregnancy on the incidence of preeclampsia. Methods: This is a cohort study design, with the entire population of the sample of pregnant women and pregnant mothers are elected by their inclusion criteria. The type of data this research is primary data taken accidental a research or a visit to the respondents if the data is needed. Results: Univariate analysis of the results obtained by the average weight gain during the study (10 weeks), the lowest and the highest 2.3 12:50 with an average of 6.17 and the Standard Deviation 2:50. As many as 12 respondents (16.7%) had preeclampsia while adding weight during late pregnancy indicates the amount of weight gain over as many as 26 respondents (36.1%). Bivariate analysis results obtained from respondents who experienced more weight gain (> 7 kg) amounted to 34.6% the proportion is greater than those who have normal weight gain is 6.5%. With the value of RR (relative risk) of 5:30. Hypothesis test results demonstrate the hypothesis is rejected with value of 0.021. Multivariate analysis showed the effect of weight gain is more at risk of 16.76 times (OR / RR indirect = 16.76) on the incidence of preeclampsia with a p-value 0.004, after being controlled by the variable age with OR of 8.92, parity primi with OR for 9:57, multi parity with OR at 2:47, and the Pre-Eclampsia family history with OR at 7:17. The confounding variables that have significant (p <0.05), is a risky age group with a p-value 0.045 and parity primi with p value 0.042.