Contraception
Internists prescribe teratogens constantly -methotrexate, ACE inhibitors and ARBs, warfarin, valproate, mycophenolate, isotretinoin- and frequently never mention contraception, which makes this a general medicine responsibility rather than someone else's specialty. Two things carry most of the decisions: effectiveness is dominated by whether a method depends on the user remembering it, and the eligibility question is answered by a published tool rather than by instinct.
🔍 Effectiveness
⚠ If you prescribe a teratogen, contraception is part of the prescription. Methotrexate, ACE inhibitors and ARBs, warfarin, valproate, topiramate, mycophenolate, isotretinoin and others are started in general medicine clinics every day, often without the conversation. Ask about pregnancy intention and current contraception before starting, document it, and revisit it at each renewal -a patient can begin a drug safely and become pregnant two years later on the same prescription. The same applies in reverse: a woman planning pregnancy needs the teratogen changed in advance, not at the first positive test.
The Tiers, and Why They Look Like That
| Tier | Methods | Why |
|---|---|---|
| Most effective under 1% failure per year | Implant, hormonal IUD, copper IUD, sterilization | Nothing depends on the user. Once placed, effectiveness does not rely on remembering, timing or resupply -which is the entire reason this tier exists and why typical use and perfect use are nearly identical here. |
| Middle roughly 6-9% typical use | Combined pill, patch, ring, injectable | The gap between perfect and typical use is the whole story: these are highly effective when used exactly as directed and considerably less so in real life. Quoting the perfect-use figure to a patient is misleading. |
| Least effective 18% or more typical use | Condoms, diaphragm, withdrawal, fertility awareness, spermicide | Heavily user- and act-dependent. Condoms remain essential for sexually transmitted infection protection regardless of what else is used, which is a separate indication from pregnancy prevention. |
The single most useful counseling move is to lead with effectiveness rather than familiarity. Patients usually arrive expecting the pill because it is what they have heard of. Presenting the tiers in order, starting with long-acting reversible contraception, materially shifts what people choose, because most have never been told that an implant or IUD is more than ten times more effective in practice than a pill. This is offering information, not steering -the choice remains theirs, and coercion around long-acting methods has a real history that makes the distinction matter.
🧪 Eligibility
Use the Published Tool, Not Instinct
- The CDC US Medical Eligibility Criteria (US MEC, 2024) classify every method against every relevant condition on a four-point scale: 1 no restriction, 2 benefits generally outweigh risks, 3 risks generally outweigh benefits (use only if better options are unavailable and with close follow-up), and 4 unacceptable health risk -do not use.
- It is a lookup table, and using it is faster than reasoning from first principles. The value for a general internist is precisely in the chronic-disease rows, where instinct tends to be either needlessly restrictive or dangerously permissive.
⚠ The Category 4 situations a general internist actually meets, all of them for COMBINED hormonal contraception (pill, patch, ring). Migraine WITH AURA at any age -this is the one most often missed, and the concern is ischemic stroke; ask specifically about aura rather than accepting "migraines". Age 35 or over AND smoking 15 or more cigarettes daily. Current or past venous thromboembolism, or known thrombophilia. Established vascular disease, ischemic heart disease or stroke. Severely uncontrolled hypertension. Current breast cancer. Severe decompensated cirrhosis or liver tumors. Systemic lupus with positive or unknown antiphospholipid antibodies. Complicated diabetes with vascular disease or long duration. Under 21 days postpartum.
The practical escape, and the point most clinicians miss: nearly every one of those contraindications applies to ESTROGEN, not to contraception as a whole. Progestin-only methods and both intrauterine devices are generally acceptable in migraine with aura, in smokers over 35, after venous thromboembolism, and in most cardiovascular disease. So "she cannot take the pill" is almost never the same as "she cannot have contraception", yet patients are routinely left with nothing after a combined method is correctly refused. The copper IUD is entirely hormone-free, which answers the remaining cases.
What You Do NOT Need Before Starting
- ⚠ A pelvic examination is not required to start hormonal contraception, nor is cervical cancer screening, nor breast examination, nor routine laboratory testing. Requiring them is a real access barrier with no safety benefit.
- What you do need: a blood pressure measurement before combined hormonal contraception, a reasonable certainty the patient is not already pregnant, and the medical history that drives the US MEC lookup.
- Bimanual and speculum examination are needed for IUD insertion itself, which is a different thing from screening before prescribing a pill.
🚨 Prescribing
Drug Interactions That Actually Matter
| Interaction | Detail |
|---|---|
| ⚠ Enzyme inducers reduce contraceptive efficacy | Rifampin and rifabutin, and the enzyme-inducing anticonvulsants -carbamazepine, phenytoin, phenobarbital, primidone, topiramate at higher doses- accelerate hormone metabolism and can cause contraceptive failure. The reliable answer is a method that does not depend on hepatic metabolism: the copper IUD, the hormonal IUD, or injectable depot progestin. Note that most antibiotics do NOT do this, contrary to widespread belief -the rifamycins are the genuine exception. |
| ⚠ Lamotrigine, in both directions | Combined hormonal contraception lowers lamotrigine levels, risking seizures, and levels then rise again during the hormone-free interval, risking toxicity. Coordinate with neurology rather than starting or stopping a combined method unilaterally in someone on lamotrigine. |
| Antiretrovirals | Some regimens interact meaningfully. Intrauterine devices are unaffected and are a straightforward answer here. |
| Obesity | Efficacy of most methods is preserved, but oral levonorgestrel emergency contraception is less effective at higher body weight, which changes the emergency recommendation below. |
Emergency Contraception
- ⚠ The copper IUD is the most effective option by a wide margin, effective up to about 5 days after intercourse, and it then continues as ongoing contraception. It is consistently under-offered because it requires a procedure.
- Ulipristal acetate is more effective than levonorgestrel and works up to 120 hours.
- Levonorgestrel is available without prescription and is best taken as soon as possible; it is less effective at higher body weight and less effective the longer the delay.
- Sooner is better for all of them, and none is an abortifacient -they prevent or delay ovulation, which is worth stating plainly because the misconception is common and affects uptake.
Non-Contraceptive Benefits Worth Naming
- The hormonal IUD substantially reduces menstrual bleeding and is a genuine treatment for heavy menstrual bleeding, which often makes it the single answer to two problems at once.
- Combined methods reduce dysmenorrhea, treat acne, and help the symptoms of endometriosis and polycystic ovary syndrome.
- Sustained reduction in ovarian and endometrial cancer risk with combined methods, persisting after discontinuation.
- Where a chronic disease makes pregnancy hazardous -pulmonary hypertension, severe cardiac disease, active lupus nephritis, recent bariatric surgery- effective contraception is itself a therapeutic intervention, and should be discussed with the same seriousness as the drug therapy.
🎤 Rounds
Pimp Questions
- Which contraceptives are in the most effective tier, and why? Implant, hormonal and copper IUDs, and sterilization -under 1% failure -because nothing depends on the user remembering anything, so typical and perfect use are nearly identical.
- What does US MEC Category 4 mean? Unacceptable health risk; the method should not be used.
- Name the Category 4 conditions for combined hormonal contraception. Migraine with aura at any age; age 35 or over with 15 or more cigarettes daily; VTE or thrombophilia; vascular disease, ischemic heart disease or stroke; severely uncontrolled hypertension; current breast cancer; severe decompensated cirrhosis or liver tumors; lupus with antiphospholipid antibodies; complicated diabetes; under 21 days postpartum.
- She has migraine with aura. Can she have contraception? Yes -just not estrogen. Progestin-only methods and both IUDs are generally acceptable. "She cannot take the pill" is not "she cannot have contraception."
- Which drugs genuinely reduce contraceptive efficacy? Rifampin and rifabutin, and enzyme-inducing anticonvulsants (carbamazepine, phenytoin, phenobarbital, primidone, higher-dose topiramate). Most other antibiotics do not, despite the common belief.
- What is the lamotrigine problem? Combined contraception lowers lamotrigine levels, risking seizures, and levels rise again in the hormone-free interval, risking toxicity. Coordinate with neurology.
- Most effective emergency contraception? The copper IUD, up to about 5 days, and it continues as ongoing contraception. Ulipristal beats levonorgestrel and works to 120 hours; levonorgestrel is less effective at higher body weight.
- What must you do before starting a combined pill? Measure blood pressure, be reasonably certain she is not pregnant, and take the history for the US MEC lookup. No pelvic exam, no cervical screening, no routine labs.
- You are starting methotrexate in a woman of reproductive age. What else does the visit require? A pregnancy intention and contraception conversation, documented, and revisited at renewal.
- Name a method that solves two problems at once. The hormonal IUD -contraception plus genuine treatment for heavy menstrual bleeding.
📣 Sample Presentation
"Ms. F is a 34-year-old woman with rheumatoid arthritis whom I am about to start on methotrexate, which is the reason contraception is part of today's visit rather than a separate conversation for someone else. She is currently using condoms alone, which is in the least effective tier at around 18% typical-use failure, and that is not adequate alongside a teratogen. On history she has migraine with aura, which is US MEC Category 4 for combined hormonal contraception because of the ischemic stroke risk, so the pill, patch and ring are all out. The important point is that this rules out estrogen rather than contraception: progestin-only methods and both intrauterine devices remain appropriate for her. Given she wants something reliable and reversible while on methotrexate, I have discussed the implant and both IUDs, leading with effectiveness rather than familiarity, and she is interested in the hormonal IUD, which will also help the heavy periods she mentioned. She is on no enzyme-inducing drugs, so metabolism is not a concern. I checked a blood pressure, confirmed she is not currently pregnant, and specifically did not require a pelvic exam or cervical screening to prescribe. I have documented the pregnancy-intention discussion and will revisit it at each methotrexate renewal, since she could conceive years into the same prescription."
Clinic Checklist
- Starting a teratogen? Pregnancy intention and contraception discussed and documented, and revisited at renewal.
- Effectiveness presented in tiers, leading with long-acting methods, while leaving the choice with the patient.
- US MEC checked for the specific condition rather than reasoned from instinct.
- ⚠ Asked specifically about AURA, not just "migraines".
- Estrogen contraindicated? Offer progestin-only or an IUD rather than leaving her with nothing.
- Enzyme-inducing drugs reviewed, with an IUD or injectable offered where present.
- Blood pressure measured before a combined method -and no unnecessary pelvic exam, screening or labs required to start.
- Condoms discussed separately for sexually transmitted infection protection.
📋 Summary
At a Glance
| Point | Detail |
|---|---|
| ⚠ Why it is YOUR job | Internists start methotrexate, ACE inhibitors and ARBs, warfarin, valproate, topiramate, mycophenolate, isotretinoin routinely. Contraception is part of that prescription -documented, and revisited at renewal, because a patient can conceive years into the same drug. |
| Effectiveness tiers | <1%: implant, hormonal IUD, copper IUD, sterilization -nothing depends on the user, so typical use ≈ perfect use. 6-9%: pill, patch, ring, injectable -the perfect-vs-typical gap is the whole story. 18%+: condoms, diaphragm, withdrawal, fertility awareness. |
| Counsel by effectiveness | Lead with the most effective tier, since most patients have never been told an implant or IUD is over ten times more effective in practice than a pill. Information, not steering -the choice stays theirs. |
| US MEC 2024 | Four categories: 1 no restriction · 2 benefits outweigh risks · 3 risks outweigh benefits · 4 unacceptable risk, do not use. A lookup table, faster and safer than instinct. |
| ⚠ Category 4 for COMBINED methods | Migraine WITH AURA at any age (ischemic stroke -ask specifically about aura). Age ≥ 35 AND ≥ 15 cigarettes/day. VTE or thrombophilia. Vascular disease, IHD or stroke. Severely uncontrolled hypertension. Current breast cancer. Severe decompensated cirrhosis or liver tumors. Lupus with antiphospholipid antibodies. Complicated diabetes. < 21 days postpartum. |
| ⚠ The escape everyone misses | Those contraindications are to ESTROGEN, not to contraception. Progestin-only methods and both IUDs are generally acceptable in migraine with aura, smokers over 35, after VTE and in most cardiovascular disease. The copper IUD is hormone-free entirely. "She can't take the pill" ≠ "she can't have contraception." |
| ⚠ Interactions | Rifampin/rifabutin and enzyme-inducing anticonvulsants (carbamazepine, phenytoin, phenobarbital, primidone, higher-dose topiramate) cause failure -use an IUD or injectable. Most other antibiotics do NOT, despite the belief. Lamotrigine: combined methods lower levels (seizures), which rise again in the hormone-free interval (toxicity) -coordinate with neurology. |
| Emergency contraception | Copper IUD is most effective (to ~5 days, then continues as contraception) and is under-offered. Ulipristal > levonorgestrel, to 120 h. Levonorgestrel is less effective at higher body weight. None is an abortifacient -say so, the misconception affects uptake. |
| Not required to start | No pelvic exam, no cervical screening, no breast exam, no routine labs. These are access barriers without safety benefit. Do check blood pressure before a combined method and reasonably exclude pregnancy. |
| Bonus indications | Hormonal IUD treats heavy menstrual bleeding (two problems, one device). Combined methods help dysmenorrhea, acne, endometriosis and PCOS, and reduce ovarian and endometrial cancer risk. Where pregnancy is hazardous, contraception IS therapy. |
The Three Things to Remember
- If you write for a teratogen, you own the contraception conversation. Not the specialist, not next visit.
- Ask about aura. It is the Category 4 most often missed, and the answer is estrogen-free, not contraception-free.
- Lead with the top tier. Most patients have never been told the difference, and it is the single change that most improves outcomes.
