I had the paraguard iud in for over 5 years . My period has always been very irregular so when I was 21, my doctor put me on birth control to regulate my cycle and with no thee risk factors, i suffered a pulmonary embolism! So hence the paraguard as opposed to the hormones! This app helped a great deal because even though I'm irregular, , it still helped me to predict my ovulation days and now we're pregnant!!!!