- Objective The study evaluates lipids profile changes during gestation in pregnancies with and without preeclampsia and/or gestational diabetes. Study Design Lipid profiles were assessed between year prior and after pregnancy in 9911 women without cardiovascular comorbidities. Results Lipid levels during gestation varied substantially with a nadir following conception and a peak at delivery. Compared to preconception levels total cholesterol levels increased from 164.4 mg/dL to 238.6 mg/dL and triglycerides (TGs) from 92.6 mg/dL to 238.4 mg/dL. The composite endpoint (gestational diabetes mellitus or preeclampsia) occurred in 1209 women (12.2%). Its prevalence increased with levels of TG—from 7.2% in the group with low TGs (<25th percentile adjusted for the gestational month) to 19.8% in the group with high TGs (>75th percentile), but was not associated with high-density lipoprotein levels. In multivariate analysis higher TGs levels, but not low high-density lipoprotein, were associated with the primary endpoint. Conclusion Lipid levels change substantially during gestation. Abnormal levels of TGs are associated with pregnancy complications.