Do oral contraceptives (OCs) cause weight gain?

From the Guidelines

Oral contraceptives generally do not cause significant weight gain for most women, despite this being a common concern. While some women may experience temporary fluid retention or slight weight fluctuations when first starting hormonal birth control, research has consistently shown that birth control pills do not cause lasting weight gain, as noted in a study published in Gastroenterology 1. Modern combined oral contraceptives contain much lower hormone doses than earlier versions and typically contain estrogen (ethinyl estradiol) and a progestin in varying amounts. Some women might notice minor side effects like bloating or breast tenderness when beginning oral contraceptives, which can create the perception of weight gain, but these effects usually resolve within 2-3 months as the body adjusts to the hormones.

Individual responses vary, and a small percentage of women may be more sensitive to hormonal changes. If weight gain is a significant concern, discussing options with a healthcare provider is recommended, as there are many formulations available with different hormone types and doses. Some progestin-only methods might cause more fluid retention than others, so switching formulations can sometimes help if side effects are bothersome. It's also worth noting that a Cochrane review of progestin-only contraceptives demonstrated evidence of weight gain associated with medroxyprogesterone acetate, but there is no clear evidence of weight change associated with combination (estrogen + progestin) oral contraceptive pills, as mentioned in the study published in Gastroenterology 1.

Key points to consider:

• Oral contraceptives are not typically associated with significant weight gain
• Temporary fluid retention or slight weight fluctuations may occur when first starting hormonal birth control
• Individual responses to hormonal changes can vary
• Discussing options with a healthcare provider can help address concerns about weight gain
• Some progestin-only methods may cause more fluid retention than others, and switching formulations may help alleviate side effects. Additionally, guidelines from the U.S. Medical Eligibility Criteria for Contraceptive Use, 2010, provide classifications for combined hormonal contraceptives, including considerations for women with certain medical conditions, such as obesity, but do not provide conclusive evidence on the impact of oral contraceptives on weight gain 1.

From the FDA Drug Label

ADVERSE REACTIONS ... Change in weight (increase or decrease) The FDA drug label mentions change in weight as an adverse reaction, but it does not specify that oral contraceptives cause weight gain, only that there can be a change in weight (increase or decrease) 2.

• The label does not provide clear evidence of weight gain as a direct result of oral contraceptive use.
• It only reports that change in weight is a possible adverse reaction. Therefore, the answer to whether oral contraceptives cause weight gain is not directly supported by the FDA drug label.

From the Research

Oral Contraceptives and Weight Gain

• The relationship between oral contraceptives and weight gain is complex, with some studies suggesting a potential link while others find no significant association 3, 4, 5, 6, 7.
• A study published in 2009 found that weight gain is one of the side effects often attributed to the use of hormonal contraception, but the increase in weight is generally small, around 3 kg over an observation interval from 6 to 24 months 3.
• Another study from 1997 noted that many women perceive that oral contraceptives cause weight gain, but most studies comparing low-androgenic oral contraceptives with medium- or high-androgenic preparations have found little or no change in weight regardless of formulation 4.
• A 2011 review of combination contraceptives found that the available evidence was insufficient to determine the effect of combination contraceptives on weight, but no large effect was evident 5.
• A 2013 review of progestin-only contraceptives found limited evidence of weight gain, with mean gain less than 2 kg for most studies up to 12 months 6.
• A randomized study published in 2007 compared the effect of two oral contraceptives on body weight and found that the distribution of body weight changes did not statistically differ between the two groups, with only 0.3% of subjects in both groups experiencing a 10% change in weight 7.

Factors Influencing Weight Gain

• The type of progestin used in oral contraceptives may influence weight gain, with some studies suggesting that preparations with less androgenic potential may minimize weight gain 4, 6.
• The dose and potency of the estrogen and progestin components of oral contraceptives may also affect weight gain, with low-estrogen-dose oral contraceptives potentially associated with less weight gain 4.
• Individual factors, such as age and body composition, may also influence weight gain associated with oral contraceptive use 3, 6.

Clinical Implications

• Concern about weight gain can limit the use of oral contraceptives, and appropriate counseling about typical weight gain may help reduce discontinuation of contraceptives due to perceptions of weight gain 5, 6.
• Healthcare providers should consider individual factors and the type of oral contraceptive when counseling patients about potential weight gain associated with oral contraceptive use 4, 6.