Missed Progestin Only Pills

A progestin-only pill is missed when it is taken later than its product window or not taken at all. The risk comes from loss of the cervical mucus effect, which fades within about a day of the last tablet and takes about 48 hours to rebuild, and from return of ovulation with pills that suppress it only partly. Risk is highest in women with regular menses and lowest in women who are fully breastfeeding and amenorrhoeic.

Product windows.

Effectiveness. Typical use: 9 pregnancies in 100 women in the first year; perfect use: 0.3 in 100. Most of the gap between the two comes from late and missed tablets.

Return of risk. Protection is lost within a day for traditional pills and is restored only after about 48 hours of correct use, which is why backup is needed.

Who is at risk. Women with regular menses, women who are not breastfeeding, patients on enzyme-inducing medicines, and patients with vomiting or diarrhoea. Women who are fully breastfeeding, under 6 months postpartum and amenorrhoeic have the lowest risk.

Assessment. Establish which pill is used, how many tablets were missed, the day of the pack, the hour of the last tablet taken, vomiting or diarrhoea, interacting medicines, whether menses are regular, and any unprotected sex in the last 5 days. Record the date of the last menstrual period.

Pregnancy exclusion. A patient is reasonably certainly not pregnant if any one of these applies:

• Baby under 6 months, fully breastfeeding and no menses since birth.
• No sex since the last normal period.
• Within 5 days of the start of a normal period.
• Negative pregnancy test and no unprotected sex in the last 3 weeks.
• Consistent and correct use of the pill before the missed tablets.

If none applies, do a sensitive urine pregnancy test. A test is also needed when menses fail to arrive after missed tablets.

Interacting medicines. Rifampicin, rifabutin, phenytoin, carbamazepine, barbiturates, primidone, topiramate, oxcarbazepine, efavirenz, ritonavir-boosted regimens, griseofulvin and St John’s wort lower hormone levels, so every tablet is effectively less protective. Advise DMPA or an intrauterine device for long-term use.

Counselling. Obtain consent, protect confidentiality and exclude coercion. Adolescents under 18 years give assent. Explain the product window, the backup period and condom use for infection protection. Do not blame the patient.

Late or missed single tablet.

• Take the missed tablet at once, even if that means two tablets on the same day, then continue one tablet daily at the usual time.
• Traditional pill, over 3 hours late: backup for 2 days.
• Desogestrel pill, over 12 hours late: backup for 2 days.
• Drospirenone pill, over 24 hours late: backup for 7 days.
• If the tablet is within its window, no backup is needed.
• A woman who is fully breastfeeding and amenorrhoeic under 6 months continues without backup.

Emergency contraception. Consider it when a missed tablet is followed by unprotected sex in the previous 5 days:

• Levonorgestrel 1.5 mg orally as a single dose (two 750 microgram tablets together, preferred) as soon as possible within 120 hours. A split dose of 750 microgram twice, 12 hours apart, is an accepted alternative.
• Ulipristal acetate 30 mg orally as a single dose within 120 hours; wait 5 days before restarting hormonal contraception and use backup meanwhile.
• Copper intrauterine device inserted within 5 days of unprotected sex; the most effective option.
• After levonorgestrel, continue the pill at once with the product’s backup period.

Two or more tablets missed. Take one tablet now, continue one tablet daily, use the backup period of the product from the last tablet taken, and assess for emergency contraception and pregnancy. Community providers refer anyone who has missed 3 or more tablets to a health facility.

Vomiting and diarrhoea.

• Vomiting within 2 hours of a tablet: take another tablet from the pack as soon as possible, then continue as usual.
• Severe vomiting or diarrhoea lasting over 2 days: count each day as missed and use backup for 2 days after recovery (7 days for drospirenone).

Drospirenone inactive tablets. Missing an inactive tablet carries no risk; discard it and start the next pack on schedule.

Switching after repeated missed tablets. If a patient repeatedly misses tablets, offer DMPA, an implant or an intrauterine device rather than repeating the same counselling.

Follow up. Review in 3 weeks if emergency contraception or backup was needed, or earlier if menses are late. Repeat the pregnancy test when 3 weeks have passed since the last unprotected sex. Document the event and the plan.

Expected effects. Missed tablets cause spotting or irregular bleeding that is harmless. A new bleed after months of regular or absent bleeding needs a pregnancy test and review.

Emergency contraception side effects. Nausea, vomiting, headache, breast tenderness and a shift in the next menses. If vomiting occurs within 2 hours of levonorgestrel or ulipristal acetate, repeat the dose.

Pregnancy. If the test is positive, stop the pill and refer for antenatal care. Exclude ectopic pregnancy when there is pain, because pill failure carries a higher share of ectopic pregnancies.

Red flags. Severe lower abdominal pain, shoulder tip pain, fainting, heavy bleeding with a positive test.

Referral and escalation. Refer any suspected ectopic pregnancy at once, and refer patients who keep missing tablets for a method change.