Taking into account that the Km needed for the conversion of Vitamin D3 to 20(OH)D3 by placental CYP11A1 is higher than that for the metabolism of cholesterol [102], only a relatively high level of Vitamin D3 will competitively inhibit excess pregnenolone synthesis, and restore local placental production of 20(OH)D3 and other derivatives by P450scc under the metabolic conditions of preeclampsia. Here, CYP11A1 is linked to preeclampsia.