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Your delayed period is mostly likely due to the minor hormonal imbalance set in by the ruptured cyst. This is a temporary phenomenon and it might take 1-3 cycles for your period to regularise.
HOWEVER if you are sexually active you SHOULD get a Urine pregnancy test done, after 1 week of your period date which was missed. Although ovulation is less likely you can never be sure. So it is better and safe to rule out pregnancy. You can go for a simple Urine Pregnancy kit which is avialable OTC.
Hope this helps
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