Reading the labels of hormonal contraceptives reveals that both weight loss and weight gain are potential side effects.
In this article, we evaluate the data that is available about birth control and weight gain, as well as provide tips for losing or preventing weight gain.
Scientific studies draw mixed conclusions in the debate over whether birth control pills, otherwise known as oral contraceptives, cause weight gain.
According to the U.S. National Library of Medicine, the potential ways that women could gain weight include:
- fluid retention
- muscle gain, as muscle weighs more than fat
- increase in body fat
These, however, are theoretical scenarios when someone is using hormonal contraceptives for birth control, and they remain unproven.
Despite the lack of scientific evidence, some women taking combined contraceptives believe that they increase their appetite and cause them to feel hungrier. Again, this is not easy to establish, as those who do not take contraceptive pills can gain weight as they age.
Why is it hard to prove birth control causes weight gain?
Scientists have difficulty creating large-scale studies to prove or disprove the theory that birth control pills cause weight gain.
To do this, researchers would have to take two groups of women and give some birth control pills with hormones, while giving placebos, or birth control pills without hormones, to others.
However, this would be difficult because people could not be sure they were in control of preventing pregnancies. Launching a very conclusive study is, therefore, difficult.
What do scientific reviews suggest?
The Cochrane Library, which conducts reviews of scientific research and evaluates available references, has published some information on birth control pills and weight gain.
The first systematic review evaluated the effects of progestin-only contraceptives on weight gain, concluding that the evidence of more than half the studies was “low-quality.”
In the studies, participants gained fewer than 4.4 pounds, on average, after 6 or 12 months of starting progestin-only birth control pills.
The second Cochrane Library review looked at the effects of combined hormone birth control pills on weight gain. These pills contain progestin and estrogen. The researchers found there was insufficient evidence to conclude that these birth control pills caused weight gain.
According to the U.S. National Library of Medicine, it is “unlikely” that birth control pills cause significant weight gain. The organization did, however, acknowledge that individual women might respond differently to medications taken.
Many of the methods of avoiding possible birth control-related weight gain are also those that prevent weight gain overall.
Examples of these methods include:
- Exercise: This consists of a person doing 30 minutes of physical activity each day, such as walking, running, aerobics, swimming, dancing, or other activities.
- Hydration: Drinking plenty of water each day helps to reduce bloating and thirst-related hunger. People may know if they are drinking enough water because they do not feel thirsty and their urine is light or pale yellow in appearance.
- Calorie restriction: Reducing calorie intake by 500 calories per day and eating between 1,200 and 1,500 calories per day for women, is one way to lose weight, according to the journal American Family Physician.
- Nutrition: Eating a healthful diet of nutritionally rich foods, such as vegetables, whole grains, and fruit encourages good weight balance. This includes avoiding foods that are not nutritious, such as those with added sugars, salt, and saturated fats.
If a woman is concerned that her birth control pills are causing her to gain weight, she should talk to her doctor.
A doctor may recommend another contraceptive type or a lower hormone dose to see if this could help a person lose weight.
Other birth control methods besides the pill are available. Most, however, utilize the same hormones that are present in birth control pills.
Examples of these methods include the birth control implant, an intrauterine device (IUD), or a birth control vaginal ring. There are hormonal and nonhormonal IUDs, the trade names of which include Mirena, Sklya, Kyleena, Liletta.
The Paraguard IUD is the only long-acting, reversible nonhormonal contraceptive.
Other nonhormonal birth control methods include a condom, diaphragm, birth control sponge, or cervical cap.
None of these methods are, however, 100 percent guaranteed to prevent pregnancy, just as taking birth control pills is not.
For a full listing of birth control types and their average pregnancy rates with typical uses, people can check out the information provided by the United States government at WomensHealth.gov.
Whenever someone starts taking birth control pills, it is important they consider the risks and benefits.
Hormonal birth control forms, for example, can increase the risks that a woman may experience blood clots and high blood pressure, according to WomensHealth.gov, although these complications are rare.
Women who smoke and are 35 years of age or older are at higher risk, however.
Other known side effects include:
- breast tenderness
- mood changes
- vaginal discharge
These side effects often subside as people become accustomed to taking the birth control pills. If side effects become too difficult to manage, however, they should see their doctor.
No conclusive scientific evidence has proven that taking birth control pills cause weight gain. Doctors also point to the fact that many people tend to gain weight as they age, which may be a reason why they perceive their birth control pills are to blame.
If, however, a woman has made no changes to her diet and exercise program, has recently begun taking birth control pills, and sees their weight increasing, she should talk to her doctor about possible reasons or potential adjustments.