Hello ma am and welcome. There can be no way the pills could have affected your uterus, the only cause for concern here is that you missed your period in between. And the pills clearly state that you need to make sure you are not pregnant before you take the pills. If you have never skipped a period in the past, then this raises some serious concern about your possible pregnany status then, which could have been affected by the second dose of the pills. But if you have always had irregular periods then it should be a more relaxed situation, but please do report to a doctor either way to find the cause. Hope this helps. Best wishes.