Smoking marijuana at five months will it effect your baby?

Absolutely 100% Yes.

If you're pregnant and you smoke weed (or are even around it), your baby could have extremely serious birth defects, or even stillbirth and death. This goes for all drugs, except those prescribed by your doctor (who should be aware of your pregnancy).

This type of activity is dangerous for you and your baby. Never jeopardize the health of your baby with ill-advised activity.

If you believe you may have jeopardized your baby, contact your doctor immediately.