Steroidal contraceptives and changes in individual plasma phospholipids: possible role in thrombosis

The changes in the levels of individual phospholipids were studies in women during prolonged use of three types of steroidal contraceptive preparation: high-dose combined pills (Noriday 1 + 50 Fe); low-dose combined pills (Nominest Fe) and progestin-only injectables (Depo-Provera). Women on high-dose combined pills had significantly higher (p less than 0.05) mean lysophosphatidylcholine (LPC), sphingomyelin (SPH), phosphatidylserine (PS) and phosphatidylethanolamine (PE) levels, respectively, than the women on low-dose combined pills, progestin-only injectables and the controls, respectively. Women on low-dose combined pills had significantly lower (p less than 0.01) mean LPC and PS levels, respectively, than the controls, while women on progestin-only injectables had significantly lower (p less than 0.01) mean PS and PE levels, respectively, than the controls. Based on the reported high activities of PS and PE in hemostasis, the PE/total plasma phospholipids, PS/total plasma phospholipids and the sum of PE and PS/total plasma phospholipids ratios were calculated to assess the possible overall effect of the changes in plasma phospholipids in steroidal contraceptive users. The results obtained using these indices agree with some earlier reports of an estrogen dose-dependent risk/incidence of thrombosis in steroidal contraceptive users. It is concluded that the observed dose-dependent estrogen-induced alterations in phospholipids, and, most especially, the PE and PS fractions may bear a relationship with thrombotic conditions.