Turns Out, Birth Control Doesn't Affect Pregnancy Tests

by Cat Bowen

You've taken out your NuvaRing for your monthly break, expecting your period, and three days later? Nothing. Not a spot. You're worried your partner has slipped one past the clear plastic goalie, and need to know. But, are pregnancy tests accurate if you're on birth control?

It's a valid question. The box that the pills, ring, or patch comes in even warns you of all the different things the hormones in birth control may affect. If it can make me more likely to have a blood clot or affect my cholesterol level, it stands to reason it could pull the wool over a pee stick, right?

As it turns out, while most birth control is hormonal, it has no affect on the result of a pregnancy test — other than hoping to prevent the need for the test in the first place, according to the Mayo Clinic. Home pregnancy tests look for pregnancy by locating and identifying varying levels of human chorionic gonadotropin, or hCG, in the urine, Planned Parenthood noted. While hCG is a hormone created in pregnancy, it's not found in hormonal birth control. (It is in fertility medication, but not birth control.) While the hormones present in birth control appear in the body in abundance during pregnancy, chiefly progesterone and estradiol, those are not the droids Clearblue Easy is looking for.

It helps to understand how birth control works. According to Harvard University, during your cycle you produce two hormones, luteal hormone (LH) and follicle stimulating hormone (FSH), which trigger the processes of ovulation and menstruation. Progesterone and estradiol are two hormones that dip and peak with the release of LH and FSH. With the addition of extra progesterone and estradiol, your body is almost tricked into thinking it's pregnant, at least enough that it prevents ovulation from occurring.

However, it does not trick your body to the point where it produces hCG, which is the pregnancy hormone created to develop the placenta and set up the growth and regulation of the embryo, according to the American Pregnancy Association. Therefore, this is the hormone that home pregnancy tests use when determining pregnancy, because it is unique to pregnancy alone and is not mimicked by birth control.

It just might be time to pee on a stick. No matter what, know that the outcome of that test would have more to do with the efficacy of the birth control, and not the efficacy of the test.