How often should bone mineral density (BMD) be monitored in patients using medroxyprogesterone for birth control?

From the Guidelines

Bone mineral density (BMD) should not be routinely monitored in patients using medroxyprogesterone for birth control, but may be considered after 2 years of continuous use, especially for those with additional risk factors for osteoporosis. The American College of Obstetricians and Gynecologists (ACOG) does not advise limiting DMPA use to 2 years or routinely monitoring bone density after that time frame 1. However, it is essential to consider other risk factors for osteoporosis and tailor counseling and recommendations to each patient. Patients using medroxyprogesterone should be counseled about measures that promote skeletal health, such as daily intake of 1300 mg of calcium and 600 IU of vitamin D and regular weight-bearing exercise 1. Some key points to consider when monitoring BMD in patients using medroxyprogesterone include:

• Initial BMD testing is not routinely recommended before starting medroxyprogesterone 1
• BMD testing may be considered after 2 years of continuous use, especially for those with additional risk factors for osteoporosis
• Patients using medroxyprogesterone should be counseled about lifestyle modifications to support bone health, including adequate calcium intake, vitamin D supplementation, regular weight-bearing exercise, smoking cessation, and limiting alcohol consumption 1. It is crucial to weigh the benefits of medroxyprogesterone as a contraceptive method against the potential risks to bone health and make informed decisions on a case-by-case basis, considering the individual patient's risk factors and medical history 1.

From the Research

Monitoring BMD in Patients Using Medroxyprogesterone for Birth Control

• The frequency of monitoring bone mineral density (BMD) in patients using medroxyprogesterone for birth control is not explicitly stated in the provided studies, but the studies suggest that BMD should be monitored regularly, especially in patients with risk factors for osteoporosis 2, 3, 4, 5, 6.
• A study published in 2002 found that patients using depot medroxyprogesterone acetate (DMPA) for more than 2 years had significantly reduced bone mass at both the lumbar spine and femoral neck, and 56% of patients had either osteopenia or osteoporosis at the lumbar spine 2.
• Another study published in 2006 found that the use of DMPA before achievement of peak bone mass may be particularly detrimental to bone, and switching to a different contraceptive does not seem to confer specific benefit in terms of bone density 3.
• A study published in 2013 found that the use of DMPA for short-term (≤12 months) has no significant effects on BMD at the spine and femoral neck, but long-term exposure to DMPA may prevent bone mass accrual in adolescents 4.
• A study published in 2006 found that long-term use of DMPA (>2 years) had a significant adverse effect on BMD and induced increased bone turnover, and recommended measuring lumbar spine BMD and biomarkers of bone turnover in women aged above 40 years who used DMPA for a long duration (2-5 years) 5.
• A study published in 2004 found that hip and spine BMD declined after one DMPA injection and this decline continued with each subsequent injection for 24 months, and that body mass index (BMI) change was inversely associated with BMD change at the hip, but not at the spine 6.

Risk Factors for Osteoporosis

• The studies suggest that patients with risk factors for osteoporosis, such as family history of height loss or tobacco smoking, should be monitored more closely for BMD changes 2, 3, 4, 5, 6.
• A study published in 2002 found that there were trends to an association of a family history of height loss or tobacco smoking with lower BMD at the lumbar spine and femoral neck 2.
• Another study published in 2006 found that younger age was associated with higher BMD, but this protective effect of age was lost once the interaction between the duration of both DMPA and oral combined pill (OCP) was introduced into the model 3.

Recommendations for Monitoring BMD

• Based on the studies, it is recommended that BMD be monitored regularly in patients using medroxyprogesterone for birth control, especially in patients with risk factors for osteoporosis 2, 3, 4, 5, 6.
• The frequency of monitoring BMD may depend on the individual patient's risk factors and medical history, but it is generally recommended to monitor BMD at least every 2 years in patients using DMPA for a long duration (2-5 years) 5.