The measurement of endometrial perfusion in norplant users: a pilot study

The use of progestogens without oestrogen is commonly associated with irregular menstrual bleeding. Oestrogens and progestogens are both thought to influence endometrial perfusion; changes in endometrial perfusion may contribute to vascular fragility and breakdown. In this study, endometrial perfusion was measured using laser-Doppler fluxmetry in women in the secretory phase of the menstrual cycle before and 4-6 weeks after insertion of the low-dose long-acting levonorgestrel contraceptive implant system, Norplant. Endometrial perfusion was also measured in women exposed to Norplant for up to 19 months. There was no significant difference between endometrial perfusion in control cycles (27.2 flux units +/- 5.5, SEM) and at 4-6 weeks after Norplant insertion (16.3 flux units +/- 5.0), a time when irregular bleeding and spotting are common. Endometrial perfusion was no different from controls after longer periods of Norplant exposure (35.7 flux units +/- 7.2). No direct relationships between endometrial perfusion and plasma concentrations of ovarian steroid hormones were demonstrated. Short-term endometrial vasomotion was largely abolished during Norplant exposure.