As summer comes to a close and autumn begins, it's important to remember the necessity of contraception! If you haven't explored contraceptive options yet, now is a great time to find a method that suits you. Over the past few months, we have discussed long-term contraceptive methods such as the insertion of intrauterine devices (IUDs) and implants. There are other long-term options as well, including the hormone injection known as Depo-Provera, which eliminates the need for daily pills or barrier methods like condoms.

1. What exactly is Depo-Provera?
Depo-Provera is a contraceptive injection that contains the hormone depot medroxyprogesterone acetate (DMPA). It is administered once every three months, or four times a year. This method is more convenient than pills, patches, or rings because it provides longer-lasting effects. Research indicates that one in five sexually active teenage and adult women in the U.S. uses this method.

2. What are the benefits of the injection?
The primary benefit is the suppression of ovulation. Progesterone inhibits the function of the pituitary gland, which releases hormones that stimulate ovulation. Without ovulation, pregnancy cannot occur. In the U.S., there is only one type of hormonal injection available for contraception.

3. What is the duration of the drug's effectiveness, and what are its advantages?
The effectiveness of Depo-Provera lasts for three months. While it is more effective than oral contraceptives, it is less effective than IUDs or implants. Once administered, the injection cannot be reversed, and its duration of effectiveness is relatively shorter compared to IUDs or implants.

4. What are the drawbacks of hormonal injection contraception?
Long-term use of Depo-Provera may lead to a decrease in bone density. Bone density refers to the amount of mineral content in a given volume of bone, which is closely related to bone strength. Factors affecting bone strength include diet, exercise, age, and lifestyle. The medication suppresses pituitary hormones, leading to a halt in ovulation and a reduction in estrogen production, which can result in decreased bone density. However, this decrease is limited and can be reversed. Therefore, women receiving Depo-Provera injections are encouraged to take estrogen supplements and rest. Additionally, long-term use of the injection may cause irregular menstrual cycles and other hormonal side effects, such as weight gain. Furthermore, since the injection requires a doctor's prescription, it necessitates an annual visit to the clinic.

5. When comparing IUDs and NEXPLANON implants, which is better for modern women?
This is subjective and depends on individual preferences. IUDs and NEXPLANON are actual medical devices implanted in the body. Depo-Provera is a short-term injectable medication that is effective for only three months. All three methods can cause irregular menstruation. IUDs are placed inside the uterus and have the least hormonal side effects. Hormonal injections can lead to temporary decreases in bone density. However, Depo-Provera is often less expensive and easier to obtain insurance coverage for compared to long-term contraceptive devices. Those interested in injection-based contraception can rest assured that any decrease in bone strength is temporary and can be fully recovered.

Written by Jennifer E. Cho, MD, FACOG
If you are interested in contraception or have not tried device insertion or removal, or injection methods, please consult a specialist. 
SOURCES:
(1) ACOG COMMITTEE OPINION 602, JUNE 2014 (REAFFIRMED 2017). “DEPOT MEDROXYPROGESTERONE ACETATE AND BONE EFFECTS”