The Link Between Hormonal Contraception and Weight
Weight gain is one of the most frequently cited reasons women consider discontinuing oral contraceptives [1.2.1]. The concern historically stems from early versions of the pill developed in the 1960s, which contained much higher doses of estrogen and progestin [1.2.1, 1.10.3]. High levels of estrogen can lead to fluid retention, causing temporary bloating and a slight increase on the scale, while some progestins (synthetic progesterone) may increase appetite [1.10.2, 1.10.3].
However, modern birth control pills contain significantly lower hormone doses [1.2.1, 1.10.3]. Numerous large-scale scientific reviews, including one analyzing 49 different studies, found no substantial evidence that combination birth control pills (containing both estrogen and progestin) cause significant weight gain for most people [1.2.2, 1.3.2]. Any minor weight fluctuation, typically under 4.4 pounds, is often due to temporary water retention that usually subsides within two to three months as the body adjusts [1.2.2, 1.10.3].
Combination Pills vs. Progestin-Only Pills
There are two main types of birth control pills:
- Combination pills: These contain both estrogen and progestin [1.2.2]. Reviews of studies on these pills have concluded they are not associated with significant weight gain [1.5.2, 1.9.3]. The estrogen dose in modern pills is too low to cause major fluid retention [1.5.4].
- Progestin-only pills (Minipills): These pills contain only progestin [1.2.2]. Some research suggests progestin-only contraceptives may be linked to modest weight gain in some individuals, averaging less than 4.4 pounds over six to twelve months [1.9.1]. However, other studies show no significant difference in weight gain compared to those not using hormonal methods [1.4.1].
The Exception: The Contraceptive Injection
The one form of contraception consistently linked to weight gain in studies is the injectable progestin shot, depot medroxyprogesterone acetate (DMPA), sold under the brand name Depo-Provera [1.3.2, 1.3.4, 1.4.2]. Research shows that DMPA users gain an average of 5.4 pounds in the first year, which can increase to 13.8 pounds after four years [1.6.3]. This is thought to be because the shot contains a higher dose of progestin, which can stimulate appetite and increase body fat rather than just water retention [1.3.2, 1.4.4, 1.6.4]. One study found that nearly 38% of users gained over 10 pounds within the first two years [1.3.1, 1.6.2].
Comparison of Contraceptive Methods and Weight Gain Potential
| Contraceptive Method | Type | Associated Weight Gain Potential |
|---|---|---|
| Combination Pills (e.g., Yaz, Loestrin) | Estrogen + Progestin | No significant evidence of long-term weight gain; possible temporary fluid retention [1.2.1, 1.9.2]. |
| Progestin-Only Pills (Minipill) | Progestin Only | Some studies show potential for modest gain (under 4.4 lbs), but evidence is inconsistent [1.9.1]. |
| The Shot (Depo-Provera) | Progestin Only (Injectable) | Consistently linked to significant weight gain (average 5 lbs in the first year) [1.3.4, 1.6.4]. |
| Hormonal IUD (e.g., Mirena, Kyleena) | Progestin Only | Not generally associated with weight gain, though some studies show a slight increase in body fat without affecting overall weight [1.2.2, 1.8.4]. |
| Contraceptive Implant (e.g., Nexplanon) | Progestin Only | Evidence is unclear and mixed; some studies show minor gain, others show no difference compared to non-hormonal methods [1.2.3, 1.8.4]. |
| Copper IUD (Paragard) | Non-Hormonal | Does not contain hormones and is not linked to weight gain [1.3.2]. |
| Patch (e.g., Xulane) & Ring (e.g., NuvaRing) | Estrogen + Progestin | Studies show average weight gain is minimal (less than 1 lb per year), similar to pill users [1.2.3]. |
Managing Weight Concerns While on Birth Control
If you experience weight changes after starting birth control, it may be coincidental and related to other factors like natural aging, diet, or exercise habits [1.2.1]. However, if you are concerned, here are some steps you can take:
- Allow Time for Adjustment: Give your body at least three months to adjust to a new pill, as initial effects like water retention often resolve on their own [1.2.2].
- Maintain a Healthy Lifestyle: Regular exercise, a balanced diet, stress management, and adequate sleep can help manage your weight regardless of contraceptive use [1.7.1, 1.7.3]. Focus on lean proteins, fruits, and vegetables while limiting processed foods [1.6.1].
- Track Your Symptoms: Keep a record of your weight and any other side effects to discuss with your doctor. This can help determine if the changes are related to your birth control [1.2.3].
- Consult Your Doctor: If weight gain persists and is a concern, speak with your healthcare provider. They can help you explore other options, such as a lower-dose pill or a non-hormonal method like the copper IUD [1.7.2, 1.11.4]. One type of progestin, drospirenone (found in pills like Yasmin), may act as a diuretic and reduce water retention [1.8.3].
Conclusion
For the vast majority of users, birth control pills are not the culprit behind significant weight gain. Extensive scientific research has debunked the myth that modern, low-dose oral contraceptives cause major changes in weight [1.9.2]. Most observed changes are minor, temporary, and often attributable to fluid retention that subsides within a few months [1.10.3]. The only contraceptive method strongly and consistently associated with weight gain is the progestin-only injection, Depo-Provera [1.11.1]. If you have concerns about weight, the best course of action is to have an open conversation with a healthcare provider to find a contraceptive method that aligns with your health needs and lifestyle. You can find more information from authoritative sources like the American Academy of Family Physicians [1.9.3].
