Contraception: Options, IUDs, Missed Pills, and Emergency Contraception

Most contraceptive counselling focuses on the list of methods. The more useful frame is how much each one asks of you.

Two documents govern this, and knowing which is which helps

United States contraceptive practice rests on two companion CDC documents, both updated in 2024 and both replacing 2016 versions. The Medical Eligibility Criteria answers “is this method safe for someone with my condition?” — it covers use by people with particular characteristics or medical conditions. The Selected Practice Recommendations answers “how is this method actually started and managed?” — initiation, follow-up, usage errors and side effects.

Both were written with a stated aim of removing unnecessary medical barriers and supporting non-coercive, person-centred counselling. If you have been told a condition rules out a method, the Medical Eligibility Criteria is the document that answers it, and it is reasonable to ask what category your condition falls into rather than accepting a flat no.

Perfect use versus typical use

Every method has two failure rates: one when used exactly as directed every time, and one as people actually use it. For methods requiring nothing of you between appointments, the two numbers are nearly identical. For methods requiring a daily action or an action at the time of sex, they diverge substantially. That divergence — not the headline number — is what a choice should turn on.

This is why long-acting reversible contraception, meaning intrauterine devices and the implant, has the lowest real-world failure rates. Not because the biology is superior, but because it removes the opportunity for the failure to occur.

Intrauterine devices

There are two families: hormonal devices, which typically lighten periods and may stop them altogether, and the copper device, which contains no hormone but often makes periods heavier and more crampy, particularly in the first months. Both are among the most effective methods available.

Insertion pain is real and has historically been under-acknowledged. This is no longer only a patient complaint: the 2024 Selected Practice Recommendations updated its guidance on medications for intrauterine device placement. It is reasonable to ask in advance what the clinic offers, and that conversation should happen before the appointment rather than during it.

Expulsion, more likely in the first months, is worth knowing about: if you cannot feel the threads, or you feel the device itself, or you have new cramping and bleeding, use backup contraception and get it checked.

Missed pills

There is no single rule, and this is where generic advice does harm. What to do depends on which type of pill you take, how many were missed, and where in the pack you are. The instructions that came with your specific pill, or your pharmacist, will give the correct answer; a general article cannot.

What is general: the risk is greatest when pills are missed at the start or end of a pack, because that lengthens the hormone-free interval. If you have missed pills and had sex, emergency contraception is worth asking about rather than assuming it is too late or unnecessary. Usage errors of exactly this kind are what the Selected Practice Recommendations exists to address, so a clinician or pharmacist has a document to consult — the answer is not guesswork.

Two changes worth knowing about

The 2024 Selected Practice Recommendations added guidance on self-administration of injectable contraception, which matters for anyone whose barrier to continuing a method is getting to a clinic every few months. It also updated guidance on managing bleeding irregularities during implant use — unpredictable bleeding is a common reason implants are removed early, and there is now specific guidance rather than only tolerating it.

Emergency contraception

Three things determine the right choice: how long it has been, your weight, and whether you want ongoing contraception.

ACOG states that regardless of body weight, the copper intrauterine device is the most effective form of emergency contraception, followed by ulipristal acetate. The copper device is highly effective when placed within 5 days of intercourse, and some studies have used it as late as 10 days. It also becomes your ongoing contraception at the same time, which no oral option does.

On weight: ACOG advises that levonorgestrel and ulipristal acetate may be less effective for women who are overweight (BMI 25–29.9) or obese (BMI 30 or greater), with levonorgestrel losing efficacy at a lower weight threshold than ulipristal. Where a hormonal option is used, ACOG recommends prescribing ulipristal acetate when possible, because it is more effective than levonorgestrel at all times up to 5 days after intercourse and in women of all weights.

One point deserves emphasis because it is sometimes got wrong in the opposite direction. ACOG is explicit that overweight and obese women should be advised that levonorgestrel may be less effective, but should not be refused or discouraged from using emergency contraception because of their weight. Less effective is not ineffective, and weight is not a reason to be turned away.

Sooner is better for all of them.

Emergency contraception prevents pregnancy; it does not end an established one, and it is not the same as medication used for termination. That confusion is common and worth naming plainly.

Contraception in your forties

Cycles becoming irregular does not mean ovulation has stopped. Pregnancy remains possible until menopause is established. What changes is which method suits you, since bleeding patterns and cardiovascular risk factors both shift in these years.

What to bring

• What matters most to you: effectiveness, bleeding pattern, privacy, reversibility, or avoiding hormones
• Your blood pressure, migraine history including whether you get aura, and any clot history
• Whether you may want pregnancy in the next year or two
• What you have used before and why you stopped

Main takeaway

Choose by how much the method depends on you remembering something. For missed pills, use the instructions for your specific pill rather than a general rule. For emergency contraception, time matters, weight matters, and the copper device is both the most effective option and ongoing contraception afterwards.