Menstrual pattern and blood loss with U-coil inert progesterone-releasing IUDs.

Menstrual blood loss (MBL) was estimated before and after insertion of the U-coil progesterone-releasing device in 37 patients. The same procedure was carried out in 39 cases fitted with an inert U-coil IUD of the same size and shape. Blood loss was estimated by the atomic abosorption technique during the preinsertion cycle and at the 1st, 3rd, 6th, 9th, and 12th postinsertion cycles.