Will hormone levels be abnormal with the use of Depo-Provera (medroxyprogesterone acetate)?

Hormone Levels with Depo-Provera (Medroxyprogesterone Acetate)

Yes, hormone levels will be abnormal when using the Depo-Provera shot, as it deliberately alters your natural hormone patterns to prevent pregnancy.

How Depo-Provera Affects Hormone Levels

Depo-Provera works by introducing synthetic progesterone (medroxyprogesterone acetate) into your system, which causes several hormonal changes:

• Serum MPA levels: Detected within 30 minutes after injection, plateauing at approximately 1.0 ng/mL for about three months, then gradually declining 1
• LH and FSH levels: Initially inhibits the midcycle LH peak, but levels generally remain in the luteal phase range 1
• Progesterone levels: Remain low (<0.4 ng/mL) for several months following injection due to ovulation inhibition 1
• Estradiol levels: Initially in early to mid-follicular phase range (approximately 50 pg/mL), then begin to rise about four months after injection when MPA levels fall below 0.5 ng/mL 1

Timeline of Hormonal Changes

The hormonal effects of Depo-Provera follow a predictable pattern:

• First 30 minutes: MPA detected in serum 1
• First 3 months: MPA levels plateau at approximately 1.0 ng/mL 1
• After 3 months: Gradual decline in MPA levels 1
• Around 4 months: Estradiol levels begin to rise as MPA levels fall below 0.5 ng/mL 1
• When MPA levels fall below 0.1 ng/mL: Ovulation resumes 1
• Up to 9 months: MPA can be detected in some women after a single injection 1

Long-term Hormonal Effects

For women using Depo-Provera for several years:

• Estradiol levels: Range between 10-92 pg/mL (mean ~40 pg/mL) 1
• Despite these lower estradiol levels, most women do not experience hot flashes, and the vaginal epithelium remains moist 1
• No significant changes in breast size are typically observed 1

Physiological Effects of Hormonal Changes

The altered hormone levels cause several changes in your body:

• Endometrium: Becomes atrophic with small, straight endometrial glands and decidualized stroma 1
• Cervical mucus: Remains thick and viscid, preventing sperm penetration 1
• Ovulation: Inhibited while MPA levels remain sufficiently high 1
• Menstrual cycle: Nearly all users experience menstrual irregularities initially, but bleeding patterns typically improve over time, with amenorrhea developing in many long-term users 2

Return to Normal Hormone Levels

After discontinuing Depo-Provera:

• Median time to ovulation: Approximately 30 weeks 2
• Return to fertility: 68% of women who become pregnant conceive within 12 months, 83% within 15 months, and 93% within 18 months from the last injection 3
• The median time to conception is 10 months (range 4-31 months) 3

Important Considerations

• Weight changes: Average weight gain of 5.4 lbs after 1 year, 8.1 lbs after 2 years, 13.8 lbs after 4 years, and 16.5 lbs after 6 years 3
• Bone mineral density: Reduces serum estrogen levels and is associated with significant loss of bone mineral density 3
• Carbohydrate metabolism: A decrease in glucose tolerance has been observed in some patients 3

Depo-Provera is highly effective at preventing pregnancy precisely because it creates these hormonal changes that inhibit ovulation, thicken cervical mucus, and alter the endometrium, providing multiple mechanisms of contraceptive action.