Best if: You're breastfeeding; You're thinking "maybe baby"
How it works: A diaphragm fits over your cervix to prevent sperm from traveling to your uterus; you have to use spermicidal cream or jelly with it each time you have sex. You can leave it in for six hours after lovemaking.
Perks: It's hormone-free and doesn't necessarily interrupt sex, since it can be inserted up to six hours beforehand.
Drawbacks: Using a diaphragm can be messy and high-maintenance; plus, spermicide may irritate sensitive vaginal tissue. You need to be fitted by a doctor and possibly refitted periodically, especially after giving birth vaginally.
Fertility returns immediately.