Late Contraceptive Injections

A contraceptive injection is late when the repeat dose is given after the scheduled date and missed when the patient has not returned. Protection depends on the grace window of the product, and the risk of pregnancy is greatest when the patient is late for or misses an injection. Whatever the delay, the patient is welcomed back and the injection is given when pregnancy is reasonably excluded.

Dosing windows.

Product	Dose and route	Interval	Earliest repeat	Latest repeat without backup
DMPA intramuscular	150 mg deep intramuscular	13 weeks	11 weeks	17 weeks (4 weeks late)
DMPA subcutaneous	104 mg subcutaneous	13 weeks	11 weeks	17 weeks (4 weeks late)
Norethisterone enanthate	200 mg intramuscular	8 weeks	6 weeks	10 weeks (2 weeks late)
Combined injectable	Medroxyprogesterone acetate 25 mg with oestradiol cypionate 5 mg, or norethisterone enanthate 50 mg with oestradiol valerate 5 mg	30 days	23 days	37 days (7 days late)

Effectiveness. Progestin-only injectables: typical use 4 and perfect use 0.2 pregnancies in 100 women in the first year. The gap reflects late and missed injections.

Pharmacology. The depot keeps ovulation suppressed for the interval plus the grace window. After the window closes, ovulation can return and pregnancy becomes possible even while the patient is amenorrhoeic.

Assessment. Record the product, the date of the last injection, the weeks since that date, unprotected sex since the window closed, bleeding pattern and breastfeeding status. Amenorrhoea is expected in injectable users and does not exclude pregnancy.

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 injection became due.
Within 5 days of the start of a normal period.
Negative pregnancy test and no unprotected sex in the last 3 weeks.
Injection received within its grace window.

A sensitive urine pregnancy test, and a pelvic examination or ultrasound where available, may be needed because amenorrhoea is common in users.

Eligibility. The usual category rules apply. The patient needs no change of product for being late. Breastfeeding under 6 weeks postpartum is category 3 for progestin-only injectables.

Interactions. Enzyme-inducing antiseizure medicines and rifamycins do not lower DMPA effectiveness (category 1), but make norethisterone enanthate category 2, so punctual dosing matters most with that product.

Counselling. Consent, confidentiality, no blame, condoms for infection protection, and a written next date before the patient leaves.

Timing	Action
Early, up to 2 weeks before the date	Give the injection (DMPA, DMPA subcutaneous or norethisterone enanthate). No backup
Late within window: up to 4 weeks for DMPA, up to 2 weeks for norethisterone enanthate	Give the injection. No backup needed
DMPA over 4 weeks late, or norethisterone enanthate over 2 weeks late	If reasonably certain not pregnant, give the injection and use backup for 7 days. If not, test now and repeat the test when 3 weeks have passed since the last unprotected sex
Combined injectable over 7 days late	Give the injection if there was no sex since the window closed, or if backup or emergency contraception covered any sex since; backup for 7 days. Otherwise take further steps to exclude pregnancy

Emergency contraception. If unprotected sex occurred in the last 5 days when the injection is overdue, offer levonorgestrel 1.5 mg orally as a single dose, or copper intrauterine device insertion, and give the injection once pregnancy is reasonably excluded. Ulipristal acetate 30 mg is an option, with a 5 day wait before the injection and backup meanwhile.

Self-injection. A patient on subcutaneous DMPA who is over 4 weeks late is assessed at the facility, has pregnancy excluded, and receives provider-administered intramuscular DMPA with backup for 7 days.

Stockouts. If the product is not available, DMPA and norethisterone enanthate are not interchangeable, but switching is acceptable at the time the repeat injection was due. Give condoms meanwhile.

Switching to other methods. Offer an implant or an intrauterine device to patients who cannot keep appointments.

Follow up. Record the new due date, review bleeding and blood pressure, and arrange the test for pregnancy at 3 weeks if backup was used.

Expected effects. Spotting after a delay is harmless.

Heavy or prolonged bleeding: exclude gynaecological disease, then give ibuprofen 400 to 800 mg orally three times daily with food for 7 to 14 days (maximum 2400 mg in 24 hours; avoid in peptic ulcer, renal impairment, severe liver disease and NSAID-sensitive asthma) or a combined oral contraceptive, one active tablet daily for 1 to 3 cycles, if oestrogen is not contraindicated and not breastfeeding under 6 months. If 8 weeks or more have passed since the last dose, giving another injection and setting a new return date may speed amenorrhoea.

Pregnancy. If the test is positive, do not inject. Refer for antenatal care and exclude ectopic pregnancy when there is pain.

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

Referral and escalation. Refer suspected ectopic pregnancy at once, and refer patients with repeated lateness for a change of method.

Late Contraceptive Injections

Overview And Clinical Pharmacology

Patient Selection And Medical Eligibility

Prescription, Administration And Follow Up

Adverse Effects, Complications And Clinical Management