I have been bleeding for about 4 days now. I am 5-6 weeks along. No severe cramping just uncomfortable. I had a vaginal ultrasound done and my OB said he could not see the baby but could see the yolk sac and that I had not had a miscarriage and to come back in a week because they usually hide at this stage. I was wondering if it was at all possible to have your period at this stage of pregnancy or if this is something I should worry about.

Bleeding that early is actually not that uncommon. A lot of women experience it as the placenta attaches and starts to create a firmer hold on the uterus. I would still keep an eye on things and follow up with your dr. You can find a lot of info if you run a search on first trimester bleeding. Here are a couple of sites that I've found helpful.

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ObGynCenterOnline:
Hope they help... don't stress too much it will only make things worse.

Hi,
How did the pregnancy go? I am experiencing the same symptoms as you...

Some women do have what is termed early pregnancy bleeding, but it must be investigated to make sure there is nothing wrong, keep in touch with your doctor. Good luck, I hope everything goes well for you.