I devoted many years to the study and teaching of prenatal yoga. I have a separate blog, geared towards students, but have found many of these posts are relevant to yoga teachers. Here are the "best of."
Benefits of Prenatal Yoga
Why your students might enjoy and appreciate this practice in addition to or instead of other classes.
Yoga Plus One
How to modify yoga for a pregnant body.
Prenatal Yoga for Bedrest
How to leverage the deep well of yogic practices when your body is on bedrest.