Serum and endometrial sodium and potassium levels with inert and copper-containing IUCDs and relation to serum steroid levels.

Serum and endometrial sodium (Na) and potassium (K) levels and serum estradiol, progesterone, testosterone and cortisol were measured in the mid-follicular and mid-luteal phases of the menstrual cycle in 20 Lippes loop and 20 CuT-200 IUCD users and 20 matched controls. Na and K were measured by atomic absorption spectrophotometry, while serum steroids were measured by RIA. Regarding steroids, the only significant difference between the three groups was a significantly lower mean mid-luteal serum estradiol in CuT-200 IUCD users compared to Lippes loop users (p less than 0.05). Regarding sodium in the control group, there was significantly lower mean mid-luteal serum and endometrial Na (p less than 0.01) that was not found in both groups of IUCD users. In the mid-follicular phase, there was significantly higher mean serum Na in both Lippes loop and CuT-200 groups compared to controls (p less than 0.05). Mean endometrial Na showed no significant difference between the three groups in both phases of the menstrual cycle. Regarding potassium in the control group, there was significantly lower mean levels in the mid-luteal-phase of the cycle (p less than 0.01) that was not seen with both groups of IUCD users. Serum K showed no significant difference in the three groups in both phases of the menstrual cycle. Endometrial K showed a significantly higher mean level in both Lippes loop and CuT-200 IUCD users compared to controls in the mid-luteal (p less than 0.01), but not in the mid-follicular phases of the cycle.