Antidepressants are one of the most common causes of lowered libido, says Minkin. But a reduced sex drive can also be from stress, anxiety, health issues, relationship troubles, or a ton of other factors. Even being in a fantastic, long-term relationship can be associated with less spontaneous desire over time. Basically, cast a wide net before throwing out your pregnancy protection. If you're still sure it's the birth control and you want to try another pill or method to see if that makes a difference, there's certainly no harm in that, says Gunter.