Jessica Burde, polyamorous writer, has released a nice little book on polyamory and pregnancy.
This is a good, clearly-written guide to considering pregnancy, contraception and the baby talks within a polyamorous relationship. I especially like its practicality and the way that it does not encourage wishful thinking. Babies and parenting are a big deal and she does not gloss over it. The book, as you might guess by the title, does deal with pregnancy and childbirth more than contraception (as it should), dealing with sensitive sensibility to the unique challenges a polyamorous family might face when deciding to have a baby. Not only that, it has good suggestions about what to do with them!
If you’re of child-bearing age, whether you want kids or not, it’s a good read to get going discussing those things you need to before you do the deed. You can get the Polyamory on Purpose Guide to Polyamory and Pregnancy in either paperback or electronic format.