Introduction

The relationship between contraceptive use and weight gain has been a topic of debate for decades. Many women report weight changes after starting hormonal contraceptives, but is there scientific evidence to support this? This blog post reviews the current literature on how different types of contraceptives may influence body weight and composition.

Types of Contraceptives and Their Potential Impact on Weight

1. Combined Oral Contraceptives (COCs)

COCs contain both estrogen and progestin and are one of the most commonly used contraceptive methods. Early versions of the pill contained high doses of estrogen, which were linked to water retention and weight gain (Lopez et al., 2016). However, modern low-dose formulations appear to have minimal effects on weight. A Cochrane review analyzing 49 trials found no significant evidence that COCs cause clinically meaningful weight gain (Lopez et al., 2016).

2. Progestin-Only Pills (POPs)

Progestin-only pills (also called the “mini-pill”) are sometimes preferred for women who cannot take estrogen. Limited evidence suggests that POPs do not significantly contribute to weight gain. However, some studies report increased appetite as a side effect, which could indirectly influence weight (Berenson et al., 2009).

3. Injectable Contraceptives (Depo-Provera)

Depot medroxyprogesterone acetate (DMPA), commonly known as Depo-Provera, has the strongest link to weight gain. Studies show that women using DMPA for a year or longer tend to gain an average of 2–3 kg, with some individuals experiencing even greater increases (Berenson et al., 2009). This weight gain is likely due to increased appetite and fat accumulation rather than water retention.

4. Hormonal Implants and IUDs

Implants (e.g., Nexplanon) and hormonal intrauterine devices (IUDs) release progestin over an extended period. Some research indicates that implants may lead to modest weight gain, whereas hormonal IUDs generally do not cause significant changes (Modesto et al., 2015). However, individual responses vary.

5. Non-Hormonal Contraceptives

Barrier methods (e.g., condoms, diaphragms) and copper IUDs do not influence hormones and therefore do not contribute to weight changes.

Potential Mechanisms Behind Contraceptive-Related Weight Gain

Several theories explain why some women experience weight gain while using hormonal contraceptives:

• Increased appetite: Some progestins can stimulate appetite, leading to higher caloric intake.
• Fluid retention: Estrogen can cause mild water retention, but this is typically temporary.
• Changes in metabolism: Some evidence suggests that contraceptives might slightly alter metabolism and fat distribution.

Individual Variability and Lifestyle Factors

It’s important to recognize that weight gain while using contraceptives is not universal. Lifestyle factors, including diet, exercise, and genetics, play a significant role in weight changes. Some women may gain weight due to life-stage factors rather than the contraceptive itself.

Conclusion

The belief that all contraceptives cause weight gain is a common misconception. While some methods, particularly DMPA injections, have been linked to increased weight, others (such as COCs and IUDs) show minimal or no significant effects in most women. Women concerned about weight changes should discuss contraceptive options with their healthcare provider to find a method that best suits their needs.

References

• Berenson, A. B., Rahman, M., & Wilkinson, G. S. (2009). Weight gain among adolescents using depot medroxyprogesterone acetate versus oral contraceptives. Pediatrics, 124(2), e281-e289.
• Lopez, L. M., Edelman, A., Chen, M., & Otterness, C. (2016). Progestin‐only contraceptives: effects on weight. Cochrane Database of Systematic Reviews, 2016(8).
• Modesto, W., de Nazaré Silva dos Santos, P., Correia, V. M., Borges, J. C., Bahamondes, L., & Bahamondes, M. V. (2015). Body weight and composition in users of levonorgestrel-releasing intrauterine system. Contraception, 91(6), 495-500.