What is prolactin?
Prolactin is a hormone produced in the pituitary gland. Its primary function is milk production. High prolactin levels inhibit secretion of FSH. Therefore, if your prolactin levels are high, your ovulation may be suppressed. This is why women who are breastfeeding (and thus have high levels of prolactin) usually don’t become pregnant. Well that the theory – it’s not always quite that simple….
What is a normal level?
When comparing prolactin levels, it'll help to note units or which continent you are in - they vary!!
Upper limit is 500-600 nmol/l in the UK (varies by lab)
< 25 ng/mL in the US
And Australia: mIU/L upper limit around 500.
What is a breastfeeding level?
Actually, levels decrease from highest (at birth) to borderline / upper normal between 6-12 months.
Does prolactin affect fertility or fertility treatment?
High levels of prolactin inhibit ovulation (and resultant periods). Obviously if trying to conceive naturally, ovulation is necessary. Once levels are approx. 70ng/ml ( = 200nmol/l) ovulation may resume.
Thus an elevated prolactin doesn’t mean you can’t get pregnant; if you are having regular periods it is likely that you are ovulating.
Conversely, we often see lactating women, with normal prolactin but still no resumption of periods. These ask why. And also, whether they should go ahead with medicated fertility treatment (which overrides natural hormones so ovulation is not required). The answer is we don’t know. There could be another, unknown factor, indicating that the body has not yet recovered and replenish after pregnancy and results in ongoing amenorrhoea.
If you have PCOS with irregular or no periods (i.e. not ovulating), then waiting for resumption of periods may well be futile. Treatment should go ahead without periods. We have members in this scenario who had treatment successfully.
What can I do to get a low result when having my blood tested?
You should have the test late in the day, not eat before and leave it as long as possible from last feed and relax!
” Prolactin concentration in blood doubles in response to suckling and peaks approximately 45 minutes after the beginning of a breastfeeding session” (Noel, Suh, and Frantz, 1974).”
Burns & Haddad (1998) note: “When drawing blood for a prolactin level, caution should be used so as not to produce an artificial elevation. Since stress can elevate the prolactin level, the patient should rest (but not sleep) before the sample is obtained. Also, the level should not follow a breast examination and should be drawn in a fasting state.”
How can I lower my actual prolactin level?
Warning – this could affect milk supply. Decreasing feed frequency e.g. night weaning can help.
The herb Vitex works directly on the pituitary to lower your prolactin levels naturally. The lowering of prolactin may lead to ovulation/periods.
For further information/reading: