Rh negative blood means that without an injection at 28 weeks, there could be problems between your blood and your baby's blood. Because your doctor has already found out that you have rh negative, you will be given the injection required at 28 weeks, and this will ensure that everything goes smoothly.
You will get a second injection within 72 hours of your baby being born, if your baby has rh positive. This ensures that should you have a second baby, you are able to ensure that your second baby will be okay as well.
The medical profession are pro's at this sort of thing, so I wouldn't worry about this. Remember, if you worry, you send messages to your baby that you are worried. Try and relax and just stay happy.
Good luck.
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