What’s the Best Birth Control for overweight or higher BMI women? We’ll explore your evidence-based options from most effective to least effective.
First some definitions from the CDC (Center for Disease Control) of the USA.
Understanding Body Mass Index (BMI)
Overweight is defined as a Body Mass Index of 25 to < 30. Body Mass Index (BMI) is a person’s weight in kilograms divided by the square of their height in meters.
BMI = kg/m2
If the BMI is 30 or higher, then it is called obese.
If the BMI is 30 to <35, then it is Class 1 obesity,
If the BMI is 35 to < 40, then it is Class 2 obesity
If the BMI is 40 or higher than is Class 3 obesity, sometimes categorized as “extreme” or “severe” obesity in research.
Birth control effectiveness studies have been conducted in women of BMIs greater than 30 to test the correlation.
BMI does NOT measure body fat. However, research shows (see references below) that BMI is moderately correlated to direct measures of body fat e.g. from skinfold thickness, bioelectrical impedance, underwater weighing, dual-energy x-ray absorptiometry (DXA) and other methods.
However, the BMI can label someone incorrectly especially if they have lots of muscle mass. For example, Arnold Schwarzenegger at his most fit had a BMI of 30.
How Being Overweight Affects Your Birth Control
From Contraceptive Technology 21st edition:
IUDs are effective for overweight or higher BMI.
Birth Control Implants are effective for overweight or higher BMI.
Depot medroxyprogesterone acetate (Depo-Provera) works for overweight or higher BMI.
The contraceptive ring (NuvaRing) has NOT been shown to be affected by body weight.
Obese women would benefit from continuous dosing for birth control pills, meaning skip the sugar/placebo/bleeding week pills. In women with higher BMIs, there is a change in the clearance of the medication (getting rid of it) and that changes the half-life of the drug, which means the drug level that you need to prevent pregnancy doesn’t happen as fast as in someone who is not higher BMI.
“Being late at the end of the period week is probably the worst time to miss pills no matter what your weight.” Dr. Alison Edelman (associate professor of obstetrics and gynecology at Oregon Health and Science University at the time) said in a podcast on Jan 14 2015.
If you’re in CA, FL, TX, AZ, WY, or CO you can sign up for an online doctor’s consult and our expert birth control doctors will take into account your BMI when prescribing your birth control.
Steinberger, J. et al., 2005. Comparison of body fatness measurements by BMI and skinfolds vs dual energy X-ray absorptiometry and their relation to cardiovascular risk factors in adolescents. Int. J. Obes., 29(11), pp.1346–1352.
Sun, Q. et al., 2010. Comparison of dual-energy x-ray absorptiometric and anthropometric measures of adiposity in relation to adiposity-related biologic factors. Am. J. Epidemiol., 172(12), pp.1442–1454.
Lawlor, D.A. et al., 2010. Association between general and central adiposity in childhood, and change in these, with cardiovascular risk factors in adolescence: prospective cohort study. BMJ, 341, p.c6224.
Flegal, K.M. & Graubard, B.I., 2009. Estimates of excess deaths associated with body mass index and other anthropometric variables. Am. J. Clin. Nutr., 89(4), pp.1213–1219.
Freedman, D.S. et al., 2009. Relation of body mass index and skinfold thicknesses to cardiovascular disease risk factors in children: the Bogalusa Heart Study. Am. J. Clin. Nutr., 90(1), pp.210–216.
Willett, K. et al., 2006. Comparison of bioelectrical impedance and BMI in predicting obesity-related medical conditions. Obes. (Silver Spring), 14(3), pp.480–490.
The above information is for general informational purposes only and is NOT a substitute for professional medical advice. Always seek the advice of your doctor/primary care provider before starting or changing treatment.