Lactational Amenorrhoea

Lactational amenorrhoea is the absence of menstruation in a breastfeeding woman, caused by suppression of ovulation by prolactin and frequent suckling.

It is a normal physiological state in the first 6 months after birth. It provides about 98 percent protection against pregnancy when three conditions are all met.

• The baby is under 6 months old.
• The woman has not had a period since delivery (bleeding in the first 56 days does not count).
• The baby is fully or nearly fully breastfed day and night.

It matters because it is a natural contraceptive method, and its loss needs a planned change to another method.

• Risk factors for early return of fertility: supplementary feeding, long gaps between feeds (more than 4 hours by day or 6 hours at night), use of pacifiers, return to work, infant sleeping through the night.
• Ovulation can occur before the first period.
• Amenorrhoea that continues long after weaning needs assessment.

Women have no periods, and may have vaginal dryness, low libido, light spotting and breast fullness. Examination is normal apart from lactation. Return of menstruation or bleeding after day 56 ends the amenorrhoea.

• Frequent feeds, night feeds, and no formula or solid foods.
• Light bleeding or discharge of lochia in the first 8 weeks is normal.
• Differential diagnosis: pregnancy, Sheehan syndrome, Asherman syndrome, hyperprolactinaemia, thyroid disease, hypothalamic amenorrhoea, premature ovarian insufficiency, contraceptive effect, polycystic ovary syndrome.
• Complications: unplanned pregnancy after the method fails, vaginal atrophy, short interval pregnancy, low bone density in prolonged lactation, delayed diagnosis of a pathological cause.

The approach is to confirm that the criteria for the method are met and to check pregnancy if in doubt.

• History of feeding pattern, age of baby, return of bleeding, supplements and contraception.
• Urine hCG if there is any doubt, after unprotected sex without the criteria, or if periods are absent for 3 months after weaning.
• If amenorrhoea persists for more than 3 months after weaning: hCG, prolactin, thyroid stimulating hormone, follicle stimulating hormone, oestradiol and pelvic ultrasound.
• Cortisol and pituitary imaging if there was severe haemorrhage with fatigue and failure of lactation.

The principle is to use the method correctly while criteria are met and to start another method before they end.

• Supportive: counselling on the three criteria; breastfeed on demand at least 4-hourly by day and 6-hourly at night; avoid formula and pacifiers.
• Start another method when any criterion fails: periods return, baby is 6 months old, supplements are given or feeds are reduced. Advise condoms for sexual protection against infection.
• Pharmacological: contraception options compatible with breastfeeding are listed below.
• Progestogen-only pills, started any time after delivery: levonorgestrel 30 micrograms oral once daily, or norethisterone 350 micrograms oral once daily at a fixed time each day.
• Depot medroxyprogesterone 150 mg IM every 13 weeks, from 6 weeks after birth.
• Implants, inserted from 4 weeks after birth: etonogestrel implant 68 mg (3 years), or levonorgestrel implant 75 mg per rod, 2 rods (5 years).
• Intrauterine methods, inserted within 48 hours of birth or after 4 weeks: levonorgestrel intrauterine system 52 mg (5 to 8 years), or copper intrauterine device (10 years).
• Combined hormonal contraception (ethinylestradiol 30 micrograms with levonorgestrel 150 micrograms) is avoided until after 6 months of breastfeeding.
• Emergency contraception: levonorgestrel 1.5 mg oral as a single dose within 72 hours of unprotected sex.
• Procedures: insertion of an intrauterine device or implant.
• Special groups: women taking rifampicin or efavirenz use depot medroxyprogesterone or an intrauterine device, since enzyme inducing drugs reduce the effect of progestogen pills and implants.
• Women with HIV use condoms with their chosen method.
• Women with Sheehan syndrome or other pituitary disease need endocrine review and cannot rely on the method.
• Red flags: heavy bleeding, fever with lower abdominal pain, absent menses 3 months after weaning, galactorrhoea after weaning, severe headache or visual loss, positive pregnancy test.
• Follow-up: review at 6 weeks, at 3 months and at 6 months to confirm the method. Review contraception at each infant immunisation visit. Do hormone tests if amenorrhoea lasts more than 3 months after weaning.