Will the Depo Provera Shot Cause Weight Gain?

Question: Will the Depo Provera Shot Cause Weight Gain?

DMPA, more commonly known as Depo Provera, is a reversible method of prescription birth control. Also known as the Depo Shot or birth control shot, each injection slowly releases the synthetic form of progesterone medroxyprogesterone acetate and protects against pregnancy for 11 to 14 weeks. DMPA prevents ovulation; it also works by thickening cervical mucus, which makes it harder for sperm to swim through. The progestin in Depo Provera can thin out or prevent uterine tissue growth. This makes it difficult for a fertilized egg to implant into the uterine wall since there’s not enough lining there to receive it.

Answer: When taken on time, the Depo shot is 99.7% effective; however, weight gain is frequently cited by women as a reason for discontinuing Depo Provera. That being said, research has shown mixed findings as to whether this method of birth control actually contributes to weight gain. Several studies have conclusively demonstrated weight gain with the use of the birth control shot while others have shown no effect of weight. It has been argued, though, that most studies that have indicated no such effect may have suffered from serious design flaws. For example, studies may have not included a comparison group of women who used nonhormonal contraception, studied weight gain retroactively, did not include a diverse enough sample or did not factor in racial effects.

The most comprehensive study completed by researchers from the University of Texas Medical Branch in Galveston investigated the body composition of 703 women (200 were African American, 247 were white, and 256 were Hispanic). All of these women were starting the use of either the pill/oral contraception (245), Depo Provera/DMPA (240), or nonhormonal contraception (218). Those women who stopped using DMPA were observed for up to 2 years to examine the reversibility of the observed weight changes.

The findings from this study revealed that Depo Provera use is associated with significant weight gain due to an increase in fat mass. Further, the increase in weight that the researchers observed is similar to that reported by the original manufacturer of Depo Provera in their study of 3857 women. Specifically, the results showed that over 36 months, DMPA use is associated with significant weight gain -– Depo Provera users (vs. those women using the pill or nonhormonal birth control) increased their:

• Weight (4.4 kg after 24 months and 5.1 kg after 36 months)
• Body fat (4.1 kg)
• Percent body fat (3.4%)
• Central-to-peripheral fat ratio (0.1)

Apparently, the degree of weight increase was dependent on the length of time the Depo shot was used. Researchers also established that DMPA-associated increases in weight are due to an increase in fat mass and not lean mass -- thought the mechanism by which DMPA causes an increase in fat mass is not understood.

The good news demonstrated by this study is that women who used nonhormonal contraception after discontinuing DMPA experienced an adjusted mean weight LOSS of 1.7 kg after 24 months (lost .42 kg in 6 months). Interestingly, the opposite effect was seen in women who switched to the pill; in fact, those women who chose oral contraception after DMPA discontinuation had an adjusted mean GAIN of 1.7 kg (gained .43 kg in 6 months) during the same time frame. So, Depo Provera-related weight gain appears to be somewhat reversible if a woman chooses to use nonhormonal contraception after stopping DMPA.

Other results show that non-obese, white DMPA users are more likely to gain weight than their obese counterparts. The researchers also warn that women who were not obese at the start of the study were twice as likely to become obese over the next 3 years if they choose to use the Depo shot rather than a nonhormonal birth control method. Finally, further analysis demonstrated that an increase in protein intake can protect against gains in weight and body fat among those women who choose to use Depo Provera.

The bottom line? Though bodyweight and fat appear to significantly increase with the use of DMPA, this side effect should be balanced against Depo Provera’s low failure rate and ease of use.

_Source:

Berenson, A. B., & Rahman, M. (March 2009). Changes in weight, total fat, percent body fat, and central-to-peripheral fat ratio associated with injectable and oral contraceptive use. American Journal of Obstetrics & Gynecology. Accessed through private subscription, 3/28/09.