The menstrual cycle with a hormonal IUD
The natural menstrual cycle is not greatly affected by the hormonal coil – ovulation still occurs. However, the presence of the hormonal coil stops the womb lining from thickening as it normally would. For most women this means that their periods become shorter, lighter and less painful. After using Mirena for a year, most women usually only have a light bleed for 1-2 days per month. After using Mirena for a year, one in five users find they stop having periods altogether – that isn’t a sign of pregnancy, but is a result of the hormone having a direct effect on the womb lining. From a medical point of view, not having periods is entirely unremarkable and is comparable to amenhorea (lack of periods) during breastfeeding.