Forgot to take extra boxes of birth control out of car. i take norethindrone tablets. they were in the car for 5-6 days and temperatures have dropped down to 30. are they still effective?

Unlikely any change: That's like keeping pills in the refrigerator or its freezer. Cold temperature should not affect the ingredients. Most likely, the pills are still the same. That means the tiny chance of getting pregnant on birth control pills is essentially the same, with the "car" pills or with "non-car" pills.

Yes: Yes they are still effective until the expiration date on the package. Actually, the cold may have helped to preserve the medication as we often tell patients to refrigerate medicine that they won't be using for up to 6 months or the expiration date.