Progestin-Only Contraceptives
Key Points
- Progestin-only contraceptives (POPs) contain no estrogen — preferred for patients with contraindications to estrogen (smoking ≥35, hypertension, migraine with aura, breastfeeding).
- Medroxyprogesterone (Depo-Provera): 150 mg IM every 3 months; 104 mg SC every 3 months — long-acting injectable; may cause bone density loss with use >2 years.
- DMPA injection effectiveness is high with on-time dosing (about every 12 weeks; typical-use efficacy about 96 percent).
- Norethindrone (Camila, Ortho Micronor): 2.5–10 mg orally daily — oral mini-pill with very narrow timing window (take at same time every day; 3-hour grace period vs. 12 hours for COC).
- Emergency contraception: Levonorgestrel (Plan B One-Step) 1.5 mg within 72 hours; ulipristal acetate (Ella) 30 mg within 120 hours (5 days) — more effective with earlier use.
- Progestin-only methods do not protect against sexually transmitted infections (STIs).
Mechanism of Action
Progestin-only contraceptives exert their effects through multiple mechanisms:
- Thickening of cervical mucus — progestin effect prevents sperm penetration (primary mechanism for oral POP)
- Suppression of ovulation — inhibits FSH and LH secretion from the pituitary (more reliable with higher doses, e.g., injectables)
- Alteration of endometrial lining — makes the uterine environment unfavorable for implantation
Unlike combined hormonal contraceptives, POPs primarily work through cervical mucus thickening rather than ovulation suppression, which is why the timing of each dose is critical.
Drug Forms and Dosing
Oral Progestin-Only Pills (Mini-Pill)
| Drug | Brand | Dose | Notes |
|---|---|---|---|
| Norethindrone | Camila, Ortho Micronor | 2.5–10 mg orally daily | Take at same time every day — 3-hour window only |
| Norethindrone acetate/ethinyl estradiol | Finzala | 1 mg norethindrone acetate/20 mcg ethinyl estradiol orally daily | 24 active + 4 placebo tablets |
Mini-Pill Timing
The progestin-only oral contraceptive has a 3-hour window (not 12 hours like COC). If more than 3 hours late, use backup contraception for 48 hours. Consistent daily timing is essential for effectiveness.
Injectable Contraceptives
| Drug | Brand | Route | Dose | Interval |
|---|---|---|---|---|
| Medroxyprogesterone | Depo-Provera | Intramuscular | 150 mg/mL | Every 3 months |
| Medroxyprogesterone | Depo-SubQ Provera | Subcutaneous | 104 mg/0.65 mL | Every 3 months |
Administration notes:
- Inject IM into deltoid or gluteus maximus; do NOT rub site after injection
- First injection should be given within 5 days of menstrual period start
- If more than 13 weeks since last injection, pregnancy test before re-dosing
Bone density concern: Long-term use (>2 years) of medroxyprogesterone is associated with decreased bone mineral density. Consider supplemental calcium and vitamin D; counsel patients about this risk. Bone density typically recovers after discontinuation. Support bone health counseling with smoking cessation and regular weight-bearing exercise.
Emergency Contraception (EC)
Emergency Contraception Timing
Effectiveness decreases with time. Both agents are NOT abortion pills — they prevent pregnancy; they do NOT terminate an established pregnancy.
| Drug | Brand | Dose | Window |
|---|---|---|---|
| Levonorgestrel | Plan B One-Step | 1.5 mg orally | Within 72 hours of unprotected sex |
| Ulipristal acetate | Ella | 30 mg orally | Within 120 hours (5 days) of unprotected sex |
Key differences:
- Ulipristal acetate (Ella) maintains greater effectiveness across the full 5-day window vs. levonorgestrel (which declines sharply after 72 hours)
- Both require a prescription or OTC access depending on jurisdiction
- Advise patients to take EC as soon as possible for greatest efficacy
Indications for Progestin-Only Methods
Progestin-only contraceptives are preferred over combined hormonal contraceptives when estrogen is contraindicated:
| Indication | Rationale |
|---|---|
| Smoking + age ≥35 | Estrogen markedly increases cardiovascular/thromboembolic risk |
| Breastfeeding | Estrogen reduces milk production; progestin-only is safe for lactating patients |
| Migraine with aura | Estrogen increases stroke risk in this population |
| Uncontrolled hypertension | Estrogen further increases cardiovascular risk |
| History of DVT or PE | Estrogen additional thromboembolic risk |
| Hormone-sensitive cancer history | Progestin-only may be lower risk than combined estrogen exposure |
Adverse Effects and Contraindications
Common Adverse Effects
| Effect | Notes |
|---|---|
| Irregular bleeding / spotting | Most common reason for discontinuation — reassure patients |
| Amenorrhea | Common with Depo-Provera injections — reassure this is expected |
| Weight gain | Reported especially with Depo-Provera |
| Headaches, mood changes, acne | Similar to other progestin-related effects |
| Decreased bone mineral density | Depo-Provera with long-term use |
Contraindications
- Pregnancy (known or suspected)
- Hormone-sensitive cancers (breast cancer, certain reproductive cancers)
- Unexplained uterine bleeding
- Active liver disease
- History of thrombotic events
- Pelvic inflammatory disease or STDs (active)
Nursing Assessment
NCLEX Focus
Key nursing priorities for progestin-only contraceptives: (1) identify patients for whom estrogen is contraindicated and recommend progestin-only methods; (2) counsel on irregular bleeding as expected (not a danger sign); (3) teach the critical 3-hour timing window for oral mini-pill; (4) assess for long-term Depo-Provera users regarding bone density.
- Assess for estrogen contraindications — smoking ≥35, hypertension, breastfeeding, migraine with aura, clotting history
- Confirm no current pregnancy before initiating
- Assess bone density risk factors for long-term Depo-Provera use
- Review medications for drug interactions (barbiturates, phenytoin, carbamazepine, rifampin, St. John’s wort reduce effectiveness)
Nursing Interventions and Patient Education
- Oral mini-pill: Emphasize strict daily timing — take at exactly the same time each day; use backup contraception if >3 hours late
- Depo-Provera: Ensure patient understands quarterly injection schedule; educate on amenorrhea as expected effect, not a concern; counsel on bone health for use >2 years
- Depo-Provera red flags: Escalate severe depression, persistent severe headache or migraine with aura, jaundice, significant/prolonged heavy bleeding, injection-site pus/persistent pain, or VTE/PE symptoms
- Emergency contraception: Teach patients to use EC as soon as possible after unprotected intercourse; clarify that EC is not an abortifacient
- Educate that irregular bleeding and spotting is common for first 3–6 months — do not discontinue without consulting provider
- Reinforce that progestin-only methods provide no STI protection — barrier methods still recommended for STI prevention
- Return-to-fertility delay: Depo-Provera may delay fertility for up to 9–12 months after last injection — counsel patients planning future pregnancy
Related Concepts
- combined-hormonal-contraceptives — When estrogen is not contraindicated, combined methods are the primary alternative.
- contraception-the-nurses-role — Nursing role in contraceptive counseling, method selection, and patient education.
- short-acting-reversible-hormonal-methods-of-contraception — Oral POPs are short-acting reversible methods alongside COCs.
- long-acting-reversible-contraception — Levonorgestrel IUS (Mirena) is a progestin-only LARC option.
- reproductive-system — Anatomy and physiology underlying contraceptive mechanisms.
Self-Check
- A 40-year-old breastfeeding patient asks about contraception. What type of hormonal contraceptive is most appropriate and why?
- A patient on Depo-Provera reports she has not had a period in 6 months. What is the priority nursing response?
- A patient asks about “the morning after pill.” She had unprotected sex 4 days ago. Which emergency contraceptive is still an option and why?