It's not necessarily that anything is happening. Were you on injectibles? Meds of any kind? It may be that you haven't O'd yet (can you post the chart link?) or just a fluke. 97.5 is a substantial rise over 96.8. And it may yet continue to rise. And one chart out of how many? I wouldn't stress over it, myself. I would wait and see 1) Whether the IUI was successful (

to you!) and 2) If there is a next cycle, what that next cycle looks like. If you continue to have low temps, I would suggest asking your doc to test your thyroid. Often very low temps are a sign of a hypoactive thyroid condition (though more often it's nothing at all). It will make you feel better to have an answer, I'm sure.
Also, check over at charting. Those ladies have seen it all. I'm sure they can help you feel better about your current chart.
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You may have to fight a battle more than once to win it. - Margaret Thatcher
Ummm........yeah...sure...I've been good.