What are the actual chances of getting yellow fever in Dakar Senegal in December?

I am pregnant and do not want to risk getting the vaccine for yellow fever now. But my husband and I have a trip planned to Dakar to see his family that he has not seen in 6 years. I am not sure what to do because I have not had the yellow fever vaccination, but if we don't go now I don't want my husband to have to wait any longer to go. Any advice would be appreciated!