Why would somebody be bleeding while they are pregnant?

Needs evaluation: Bleeding at anytime during pregnancy should be evaluated. Some reasons are not worisone, some are. The cause also depends on the trimester. At times, sex during pregnancy may result in cervical irritation with blood tinged mucus being seen. This is less worrisome than other events such as those that invilve the placenta. Always talk to your OB about these events, and do it without delay.