Knowledge Centre
Hormones & blood testsDraft: awaiting clinical review
Prolactin
A pituitary hormone; raised levels can interfere with ovulation and periods.
Overview
Prolactin's main role is milk production after childbirth. Outside pregnancy and breastfeeding, raised levels can suppress ovulation.
Symptoms of raised prolactin can include irregular or absent periods and nipple discharge.
What is well established
- Prolactin can be mildly raised by stress, recent breast stimulation, some medications and an underactive thyroid, so a raised result is often repeated.
- Some people have 'macroprolactin', a form that is usually biologically inactive; laboratories can test for it.
- Persistently high levels may need a pituitary scan, and effective treatments are available.
Uncertain or emerging evidence
- The significance of very mild, symptom-free rises in prolactin for fertility is less clear.
This guide is general information and does not replace advice about your own circumstances. Clinical review pending.