Spotting During Pregnancy: Risks & What to Do

Question
I am 13 wks pregnant, last week, at 12wks pg I began spotting after exercise. I had registered to do a 1/2 marathon before I found out I was pg, and when I asked my Dr. if it were still OK to do it, she said it would be fine, but to watch my HR, stay hydrated, and don't overheat. (I am an amateur triathlete and I'm used to a high level of activity, I ran until 36wks pg with my now 19 mo son).

Last Saturday I did the 1/2 marathon with a friend and we talked the entire way, I drank tons of water, and the temps were in the 40's, so no chance of overheating. I felt great the entire time. Saturday afternoon, about 4-5 hours after finishing I began spotting (very light, bright red blood only when I wiped). By late Sat. night/early Sunday AM the spotting stopped, and I never experienced any cramping.

I went in to see my OB/Gyn Monday morning, she found the heartbeat right away, but did an u/s just to make sure baby was OK. It was discovered that I have marginal placenta previa and a slight tear in the placenta with some bleeding. The doctor told me to abstain from intercourse and refrain from doing any exercise that could elevate my heat rate (basically the only thing I can do is slow walking).

Of course do not want to do anything to jeopardize this pregnancy, but I have not had any bleeding since last week, so I'm wondering if I still need to abstain from sex and exercise?

Answer
If you have a marginal placenta previa, that means that the edge of the placenta is covering the opening of the cervix (cervical os). If the cervix opens slightly, you can bleed to death. Therefore, we recommend that you avoid heavy lifting, sexual intercourse, and exercise until the placenta moves away from the cervical os. This usually occurs by 24 weeks gestation. If the placenta moves towards the cervix and becomes a complete placenta previa, you will be advised to avoid activity for the entire pregancy and to deliver by cesarean section as soon as the baby's lungs are mature. If the placenta moves away by the next sonogram you can return to all your activities without worry. Good luck.