birth control weight gain

Why does birth control make you gain weight

Weight gain is often considered a side effect of using combination contraceptives (that is, an estrogen plus a progestin) 1) and many women and clinicians believe that an association exists. Birth control pills also called oral contraceptives or just “the pill” contain man-made forms of 2 hormones called estrogen and progestin 2). These hormones are made naturally in a woman’s ovaries. Birth control pills can contain both of these hormones or have progestin only. Both estrogen and progestin hormones in the birth control pills prevent a woman’s ovary from releasing an egg during her menstrual cycle (called ovulation). They do this by changing the levels of the natural hormones the body makes. Progestins also make the mucus around a woman’s cervix thick and sticky. This helps prevent sperm from entering the uterus.

  • The “mini-pill” is a type of birth control pill that contains only progestin, no estrogen. These pills are an option for women who do not like the side effects of estrogen or who cannot take estrogen for medical reasons.

Weight gain is thought to be a side effect of birth control methods. Many women and healthcare providers believe that pills and patches cause weight gain. However, there are no significant differences among combined oral contraceptives in terms of weight gain 3). Furthermore, a causal relationship between combination contraceptives and weight gain has not been established 4). Many women consider weight gain a side effect of using hormonal contraceptives 5), 6). This perception may be based on self-report of side effects rather than actual weight changes 7), 8), 9).

Concern about weight gain can deter the initiation of contraceptives and cause early discontinuation among users. In a United States study of bone mineral density, weight gain was reported more often by women using depot medroxyprogesterone acetate (DMPA) than those using a low-dose oral contraceptive 10). Weight gain was the most common side effect reported with DMPA use, after menstrual disturbances, in a New Zealand study 11), and was the most common self-reported side effect in a study from Iran 12). Reported weight gain has been a major reason for discontinuing DMPA use in the US 13). Some evidence suggests that DMPA is a concern for adolescents who are already obese 14). From a survey of Latin American women across four countries, more women believed levonorgestrel-releasing intrauterine contraception (LNG-IUC) led to weight gain, mood swings, and infertility compared with copper IUC 15). In a US study, more women reported weight gain as a side effect for the etonogestrel implant than for LNG-IUC 16). Weight gain was also reported for levonorgestrel implants 17). The gain may have been greater among women in the US than among those in China, and may be partly attributable to differences in dietary habits.

  • For most women, birth control pills, vaginal rings and contraceptive skin patches are very unlikely to affect their weight much. Many women slowly gain weight over the years, whether or not they use hormonal contraception 18).

A systematic review of randomized controlled trials did not find a causal connection between combined hormonal contraceptives and weight gain 19), whereas a Cochrane review found the evidence to be insufficient 20). Extended-cycle combined oral contraceptives do not cause more weight gain than standard regimens 21). A randomized prospective trial of two combined oral contraceptive regimens and the ethinyl estradiol/etonogestrel vaginal ring (Nuvaring) did not find significant weight gain in any group 22).

Effects birth control and weight gain are the subject of debate

Women who stop taking the pill often do so because they think it has been causing them to gain weight. Clinical studies in this area are contradictory: Some women said that they gained weight, while others reported losing weight. This is why both weight gain and weight loss are listed as possible side effects on the product information of hormonal contraceptives.

If people put on weight it is usually due to one of the following changes:

  • Fluid retention
  • An increase in muscle tissue (because muscle is heavier than other tissue)
  • An increase in body fat

Theoretically, hormonal contraceptives could contribute to weight gain if they led to fluid retention 23) and increased body fat 24). Also, combined contraceptives are sometimes believed to increase appetite. But it’s not that easy to say whether that’s true because women who don’t use hormonal contraceptives also gain weight as they age.

The research results are uncertain

In order to find out whether the birth control pill actually influences body weight, doctors would need studies with one group of women who use hormonal contraceptives over a long period of time and another group who do not. Then the groups could be compared to see if there are any differences in their weight.

In 2014 researchers from the Cochrane Collaboration 25) looked for such good-quality studies on hormonal contraceptives in which weight was recorded. They were only able to find a few studies that compared hormonal contraceptives with “fake” hormonal contraceptives (placebos) and measured the impact on weight. This is not that surprising, though. Because hormonal contraceptives are so reliable, not many women are willing to use contraceptives that could be less effective or may even be placebos and not work at all.

None of the studies found by the researchers show a clear link between hormonal contraception and weight gain 26). But these studies did not have enough participants and were not well-designed to be able to provide a definite answer. In addition, most of the studies didn’t record the participants’ weight very carefully. At most, only the number of women who reported that they stopped taking the pill because of weight gain was recorded. So it’s not possible to say for sure whether the participants who used hormonal contraceptives gained more weight than the women in the other group.

A major effect on weight is unlikely

Because of this, one group of researchers also looked for studies where different combined contraceptives were compared with one another and weight was carefully recorded. They found 45 studies in which many different types of hormonal contraceptives were compared. So it’s difficult to tell how the individual types affect weight.

What’s more, no link was found between hormone dosage and weight gain. If hormones really did influence weight gain, then you would expect higher doses to lead to more weight gain. Such a link was not established.

On the whole, the researchers concluded that it seems very unlikely that hormonal contraceptives cause major weight gain. If there were a strong effect, it would have been noticed in the studies. But this doesn’t rule out the possibility that individual women could in fact gain weight.

Birth control shot may make you gain weight

Many clinicians and women also believe that progestin-only contraceptives cause weight gain 27). Progestin-only contraceptives are appropriate for many women who cannot or should not take estrogen. Progestin-only contraceptives do not contain estrogen, unlike combined hormonal contraceptives that have both progestin and estrogen. Therefore, progestin-only contraceptives are appropriate for women who cannot or should not take estrogen 28). Progestin-only contraceptives include injectables, intrauterine contraception, implants, and oral contraceptives. Many progestin-only contraceptives are long-acting, cost-effective methods of preventing pregnancy. However, concern about weight gain can deter the initiation of contraceptives and cause early discontinuation among users.

In Medical Eligibility Criteria, progestin-only contraceptives are category 1 for women who are obese (body mass index (BMI) ≥ 30 kg/m2) 29), 30), 31). Category 1 is a condition with no restriction for use of the contraceptive method. For obese adolescents, long-acting injectable depot medroxyprogesterone acetate (DMPA sometimes called Depo-Provera, the Depo shot) is category 2 due to possible effects on bone mineral density. For category 2, method advantages generally outweigh the theoretical or proven risks. Progestin-only contraceptives are also category 1 for breastfeeding women who are at least six weeks postpartum. Combined hormonal contraceptives (containing both estrogen and progestin) are category 3 for such women until six months postpartum 32). In the US, combined hormonal contraceptives are considered category 2 by one month postpartum 33).

Worldwide, intrauterine contraception (IUC) is the most commonly used reversible method among women married or in union 34). In the US in 2012, IUC use was low compared with oral contraceptive use 35). However, use of long-acting reversible methods (LARC) increased to 11.6% from 8.5% in 2009 36). Nearly three-fourths of IUC users were using hormonal IUC. Worldwide, the method used most frequently after IUC is oral contraceptives, which include combined oral contraceptives (COCs) and progestin-only pills (POPs). In the least developed countries, injectables are most commonly used, followed by oral contraceptives 37). Some injectable contraceptives contain both estrogen and progestin, while others like DMPA are progestin-only.


The long-acting injectable depot medroxyprogesterone acetate (Depo-Provera) is the only hormonal contraceptive that is consistently associated with weight gain. A prospective study found that women who used Depo-Provera gained an average of 11.2 lb (5.1 kg) over 36 months, whereas women who used combined oral contraceptives did not gain any weight 38), 39). However, in a 2016 Cochrane review 40) that included 22 clinical studies involving a total of 11,450 women. By contraceptive method, the review has 16 studies of depot medroxyprogesterone acetate (DMPA), 4 of levonorgestrel-releasing intrauterine contraception (LNG-IUC), 5 for implants, and 2 for progestin-only pills. More than half of the studies had low quality evidence. Overall these 22 studies showed limited evidence of change in weight or body composition with use of progestin-only contraceptives 41). Mean weight gain at 6 or 12 months was less than 2 kg (4.4 lb) for most studies. Those with multiyear data showed mean weight change was approximately twice as much at two to four years than at one year, but generally the study groups did not differ significantly. Therefore, appropriate counseling about typical weight gain may help reduce discontinuation of contraceptives due to perceptions of weight gain.

What causes weight gain when using birth control ?

A number of factors can play a role in weight gain. Weight gain and obesity results from a combination of causes and contributing factors, including individual factors such as behavior, stress, lack of sleep and genetics. Behaviors can include dietary patterns, physical activity, inactivity, medication use and other exposures. Additional contributing factors in our society include the food and physical activity environment, education and skills, and food marketing and promotion. Some of these factors are discussed briefly below.

Energy imbalances cause the body to store fat

Energy imbalances can cause overweight and obesity. An energy imbalance means that your energy IN does not equal your energy OUT. This energy is measured in calories. Energy IN is the amount of calories you get from food and drinks. Energy OUT is the amount of calories that your body uses for things such as breathing, digesting, being physically active, and regulating body temperature.

Overweight and obesity develop over time when you take in more calories than you use, or when energy IN is more than your energy OUT. This type of energy imbalance causes your body to store fat.

Your body uses certain nutrients such as carbohydrates or sugars, proteins, and fats from the foods you eat to:

  • make energy for immediate use to power routine daily body functions and physical activity.
  • store energy for future use by your body. Sugars are stored as glycogen in the liver and muscles. Fats are stored mainly as triglycerides in fat tissue.

The amount of energy that your body gets from the food you eat depends on the type of foods you eat, how the food is prepared, and how long it has been since you last ate.

Risk Factors


Unhealthy lifestyle habits

  • Lack of physical activity


Unhealthy eating behaviors


  • Eating too much saturated and trans fats
  • Eating foods high in added sugars

Not enough sleep


High amounts of stress


Food and Activity


The world around you influences your ability to maintain a healthy weight. For example:

  • Food advertising encourages people to buy unhealthy foods, such as high-fat snacks and sugary drinks 43).




The key to achieving and maintaining a healthy weight isn’t short-term dietary changes; it’s about a lifestyle that includes healthy eating and regular physical activity.

  • Body Weight Planner.


  • ChooseMyPlate.


  • SuperTracker website:

To find out What and How Much To Eat, you can use a FREE, award-winning, state-of-the-art, online diet and activity tracking tool called SuperTracker 46) from the United States Department of Agriculture Center for Nutrition Policy and Promotion 47). This free application empowers you to build a healthier diet, manage weight, and reduce your risk of chronic diet-related diseases. You can use SuperTracker 48) to determine what and how much to eat; track foods, physical activities, and weight; and personalize with goal setting, virtual coaching, and journaling.

  • BMI Calculator Adults.
  • BMI Calculator Children.

To find out about your body mass index (BMI), you can use a FREE online BMI calculators from the Centers for Disease Control and Prevention (CDC) – for Adults 49) and for Children 50)

Community Environment


Many environmental factors can increase your risk for overweight and obesity:


Exposure to chemicals known as obesogens

Scientists are exploring the role that chemicals may play in weight gain and obesity. Some of these chemicals are toxic to animals and humans, and some interfere with how the body’s hormones function. The ones that impact hormones are called endocrine disrupting chemicals, or endocrine disruptors, and are linked to a variety of diseases 51). Some endocrine disruptors have been shown to be obesogens, or involved in weight gain, and may be contributing to the obesity problem in this country.


How obesogens work in the body

Unhealthy diet and lack of exercise are the main factors that contribute to weight gain and obesity, but studies have found that obesogens may also be playing a role. Obesogens do not directly cause obesity, but they may increase the sensitivity, or susceptibility, to gaining weight, especially when the exposures occur during development.

Obesogens are believed to work in several ways.

They may change how a person’s fat cells develop, meaning they may increase fat storage capacity or the number of fat cells.

Also, obesogens may make it more difficult to maintain a healthy weight, by changing how the body regulates feelings of hunger and fullness, or increasing the effects of high fat and high sugar diets.

Examples of chemicals that may be obesogens

  • Cigarette smoke
  • Air pollution
  • Tributyltin, a chemical that is widely used as a fungicide and heat stabilizer in polyvinyl chloride (PVC) piping
  • Flame retardants
  • Phthalates, a broad class of chemicals that are added to many consumer products to make them softer
  • Bisphenol A
  • Some pesticides
  • Polychlorinated biphenyls (PCBs), industrial chemicals that were used widely in the past in products such as paints, cements, fluorescent light ballasts, sealants, and adhesives.

Cigarette Smoke

Cigarette smoke contains a number of toxic chemicals and irritants. People with allergies may be more sensitive to cigarette smoke than others and research studies indicate that smoking may aggravate allergies.


Common symptoms of smoke irritation are burning or watery eyes, nasal congestion, coughing, hoarseness and shortness of breath presenting as a wheeze.

More than 58 million nonsmokers in the United States are still exposed to secondhand smoke, even though cigarette smoking rates are dropping and many states prohibit smoking in public places such as worksites, restaurants, and bars. In all, about 1 of every 4 nonsmokers is exposed to the dangerous chemicals in secondhand smoke.

Secondhand smoke exposure occurs when nonsmokers breathe in tobacco smoke exhaled by smokers or when they breathe the smoke from burning tobacco products. The Environmental Protection Agency has classified secondhand smoke as a Group A carcinogen—an agent that is known to cause cancer in humans—and the Surgeon General has concluded that there is no safe level of exposure to secondhand smoke.

Secondhand smoke contains dangerous chemicals that can damage the lungs and heart. It is known to cause heart disease and cancer in adult nonsmokers, and even brief exposure can trigger a heart attack or stroke. Secondhand smoke can also cause sudden infant death syndrome (SIDS), respiratory infections, ear infections, and asthma attacks in infants and children. Every year, exposure to secondhand smoke causes:

  • 41,000 adult nonsmokers to die from heart disease or lung cancer
  • 400 infants to die from SIDS

Preventive Strategies

  • Don’t smoke and if you do, seek support to quit smoking.
  • Seek smoke-free environments in restaurants, theaters and hotel rooms.
  • Avoid smoking in closed areas like homes or cars where others may be exposed to second-hand smoke.

Air Pollution



  • Tabacco Smoke


  • Gases (carbon monoxide, radon, etc.)
  • Household products and chemicals
  • Tobacco smoke
  • Mold and pollen


What health effects are linked to air pollution ?


In 2013, the World Health Organization concluded that outdoor air pollution is carcinogen to humans 52).

How can I reduce my risk for air pollution exposure ?



Flame Retardants

Flame retardants are chemicals that are added or applied to materials in order to slow or prevent the start/growth of fire 53). They have been used in many consumer and industrial products since the 1970s, to decrease the ability of materials to ignite.

Flame retardants are often added or applied to the following products:

  • Furnishings, such as foam, upholstery, mattresses, carpets, curtains, and fabric blinds.
  • Electronics and electrical devices, such as computers, laptops, phones, televisions, and household appliances, plus wires and cables.
  • Building and construction materials, including electrical wires and cables, and insulation materials, such as polystyrene and polyurethane insulation foams.
  • Transportation products, such as seats, seat covers and fillings, bumpers, overhead compartments, and other parts of automobiles, airplanes, and trains.

Many flame retardants have been removed from the market or are no longer produced. However, because they do not easily break down, they can remain persistent in the environment for years. They can also bioaccumulate, or build up in people and animals over time.

How are people exposed to flame retardants ?

People can be exposed to flame retardants through a variety of ways, including diet; consumer products in the home, car, airplane, and workplace; and house dust 54).

  • These chemicals can get into the air, water, and soil during manufacture.
  • Chemicals can leak from products into dust and into the air.
  • Dust can get on hands and food and then into the mouth when food is eaten.
  • Through e-waste or the uncontrolled burning and dismantling of electronic and electric waste.

What are some of the potential health effects associated with flame retardants ?

Although flame retardants can offer benefits when they are added to some products, a growing body of evidence shows that many of these chemicals are associated with adverse health effects in animals and humans. These include:

  • Endocrine and thyroid disruption
  • Impacts to the immune system
  • Reproductive toxicity
  • Cancer
  • Adverse effects on fetal and child development
  • Neurologic function

Who is most vulnerable ?

Children may be particularly vulnerable to the toxic effects of these chemicals, because their brain and other organs are still developing. Hand-to-mouth behavior and proximity to the floor increases the potential of children to be exposed to flame retardants. Researchers have found that children have higher concentrations of flame retardants in their bodies than adults.

Are there different types of flame retardants ?

There are hundreds of different flame retardants. They are often broken into categories based on chemical structure and properties. In general, flame retardants are grouped based on whether they contain bromine, chlorine, phosphorus, nitrogen, metals, or boron.

Brominated flame retardants — Contain bromine and are the most abundantly used flame retardants. Used in many consumer goods, including electronics, furniture, building materials, etc. and have been linked to endocrine disruption among other effects.

Polybrominated diphenyl ethers (PBDE’s) —PBDEs do not chemically bind with the products to which they are added (furniture, electronics, etc.) so they easily release from these products and enter air and dust. PBDEs can lower birth weight/length of children, and impair neurological development.

Tetrabromobisphenol A (TBBPA) — Widely used to make computer circuit boards and electronics. Also used in some textiles and paper, or as an additive in other flame retardants.

Hexabromocyclododecane (HBCD) — An additive primarily used in polystyrene foam building materials. The primary risk to humans is from leaching out of products and getting into indoor dust. Low levels of HBCD have also been found in some food products.

Organophosphate flame retardants (OPFRs) — With the phasing out of PBDEs, some OPFRs have been identified as replacements.

What is Bisphenol A (BPA)

Bisphenol A (BPA) is a chemical produced in large quantities for use primarily in the production of polycarbonate plastics and epoxy resins 55).

Where is BPA found ?


How does BPA get into the body ?



Why are people concerned about BPA ?




  • Reduce your use of canned foods.
  • Use baby bottles that are BPA free.



Health consequences

The most sensitive time for exposure to obesogens is during early development — as a fetus or during the first years of life — when the body’s weight control mechanisms are being developed.

Obesity is a disease itself, but other diseases or disorders that develop as a result of, or in combination with obesity, such as cardiovascular disease, liver disease, diabetes, arthritis, and others, also can contribute to health problems associated with weight gain.


Try to minimize exposures to environmental chemicals. This is often challenging, since it is hard to know where and what products contain these chemicals.

Some general advice is to:

  • Eat fresh fruit and vegetables
  • Reduce use of plastics
  • Do not use plastics in the microwave (unless it’s microwave safe)
  • Purchase furniture that has not been treated with flame retardants
  • Choose fragrance-free products.


Research shows that genetics plays a role in obesity. Genes can directly cause obesity in such disorders as Prader-Willi syndrome, Bardet-Biedl syndrome
Alström syndrome and Cohen syndrome.


Health Conditions

Some hormone problems may cause overweight and obesity, such as underactive thyroid (hypothyroidism), Cushing syndrome and polycystic ovary syndrome (PCOS).

Polycystic ovary syndrome (PCOS) is a condition that can cause infertility, enlarged ovaries, irregular menstrual cycles, excessive body or facial hair, acne, and obesity. Also called PCOS. POCS increases the risk for diabetes, heart disease, high blood pressure and endometrial cancer.


Cushing’s syndrome. People with this condition have high levels of glucocorticoids, such as cortisol, in the blood. High cortisol levels make the body feel like it is under chronic stress. As a result, people have an increase in appetite and the body will store more fat. Cushing’s syndrome may develop after taking certain medicines or because the body naturally makes too much cortisol.



Medicines such as corticosteroids, antipsychotics, antidepressants, antiepileptics, and antihyperglycemics can cause weight gain and lead to overweight and obesity.

Talk to your doctor if you notice weight gain while you are using one of these medicines. Ask if there are other forms of the same medicine or other medicines that can treat your medical condition, but have less of an effect on your weight. Do not stop taking the medicine without talking to your doctor.

Stress, Emotional Factors, and Poor Sleep



What are the treatments for obesity and overweight ?

To maintain a healthy weight, it is important to create a balance between the calories eaten and the calories burned through physical activity and bodily functions. To lose weight, a person usually needs to reduce calories and increase physical activity.

If lifestyle changes are not enough, medicines and weight-loss surgery also are options for some people who need to lose weight.

What are some tips for healthy eating ?

  • Eat a diet low in saturated fats, trans fats, cholesterol, salt (sodium), and added sugars.
  • Drink more water instead of sugary drinks.

How much physical activity does an adult need ?


  • Adults age 18 and older need at least 30 minutes of physical activity on 5 or more days of the week to be healthy.
  • Children and teens need at least 60 minutes of activity a day for their health.

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