Rethinking IUGR in preeclampsia: dependent or independent of maternal hypertension?

Chronic hypertension (CHTN) is a risk factor for both intrauterine growth restriction (IUGR) as well as preeclampsia. This study was performed to: (1) describe the prevalence of IUGR in women with preeclampsia (with and without CHTN) compared with controls, (2) investigate the relationship between preeclampsia and maternal CHTN with IUGR, and (3) investigate the relationship between IUGR and severity of preeclampsia.

A case-control study was performed. Cases were patients identified with preeclampsia. Controls were patients presenting for delivery at term (>or=37 weeks). IUGR prevalence by case-control status, or severity of disease was evaluated using Pearson chi(2) tests. Multivariable logistic regression was used to control for confounders.

In all, 430 cases and 568 controls were studied. Preeclamptic women have a 2.7 (CI (1.94 to 3.86)) and 4.3 (CI (2.58 to 7.17)) times increased odds of having a fetus with IUGR at <10 and <5% compared with controls in adjusted analyses. There was a significant interaction between CHTN and IUGR. Therefore, in women without CHTN, women with PEC had increased odds of IUGR, whereas in women with CHTN, there was no difference in odds of IUGR in women with or without preeclampsia. Within the cases, severe preeclampsia was associated with IUGR<10% (AOR=1.82 (1.11 to 2.97)) but not IUGR<5% (AOR=1.6 (0.85 to 2.86)).

Preeclampsia is independently associated with the development of IUGR. As suggested earlier, women with CHTN do not have the highest prevalence of IUGR, suggesting disparate pathways by which IUGR develops in women with superimposed preeclampsia compared with preeclampsia alone.