How Prolactin Affects Your Periods

by Deborah Maragopoulos FNP | Apr 5, 2023 | Women's Health, Infertility | 0 comments

Can prolactin cause irregular periods and infertility? Let's talk about it.

Prolactin is a hormone that is produced by the hypothalamus and released by the pituitary gland.

The hypothalamus creates prolactin-releasing hormone and prolactin-inhibiting hormone also known as dopamine. Prolactin-releasing hormone stimulates the pituitary gland to release stored prolactin in a circadian rhythm with the highest levels at night.

As a nocturnal hormone, prolactin induces the immune system to do its job, particularly the thymus to start programming white blood cells. Prolactin also helps to deepen your sleep. In pregnant women, prolactin is naturally high because it induces enough of an immune response to help stimulate her fetus to develop an immunity postnatally. High levels of prolactin in a pregnant woman acts to block her hormone receptor sites so the excessive levels of pregnancy hormones do not cause abnormal growth in the mother, but do help to maintain the pregnancy and stimulate the baby to develop.

The normal serum levels of prolactin in women are 5- 30ng/ml unless you’re pregnant or lactating. If you’re breastfeeding, you will have very high prolactin levels because prolactin's job is to induce milk production.

Prolactin secretion follows a circadian rhythm - low during the day, high at night. I draw my patient's prolactin levels between 8 and 9 am and make sure there's no nipple stimulation 24 hours before because that will artificially raise prolactin. By 9 am I expect prolactin to be under 9ng/ml which indicates that the hypothalamus has been producing enough dopamine to turn prolactin off.

High prolactin can cause irregular periods because prolactin naturally blocks steroid receptor sites on your cells.

Without that feedback of estrogen and progesterone in the hypothalamus, the pituitary gland is not stimulated to produce FSH and LH to then stimulate the ovaries to produce adequate amounts of sex hormones. Your periods become irregular, unusually heavy, even absent.

High prolactin decreases the production of estradiol by your ovaries and inhibits ovulation. High prolactin levels will cause infertility. Treating high prolactin levels even dyscircadian prolactin levels can make a big difference in improving menstrual cycle regularity and fertility.

If your prolactin levels are way higher than normal, it’s called hyperprolactinemia. Hyperprolactinemia can be treated by inducing prolactin-inhibiting hormone with a dopamine agonist. I use a short-acting dopamine agonist called bromocryptine just in the morning to reset normal prolactin circadian release. Using bromocriptine orally has side effects - high blood pressure and headaches, so I recommend intravaginal use. Studies show that bromocryptine is well absorbed through the vagina and highly effective. By bypassing the liver, we avoid side effects.

My patients who support their hypothalamus with Genesis Gold® find that their prolactin levels naturally drop and are better maintained if dopamine agonists must be used. Many infertile patients have gotten pregnant just by using Genesis Gold® alone.

If you have any questions about prolactin and periods, please join me in our Hormone Support Group where I answer your questions live. You can access it by signing up for my free Hormone Reboot Training.

References:

Prolactin and menstrual irregularities

Frequently Asked Questions:

Can your hypothalamus cause weight gain?

Yes. The hypothalamus is the master regulator of metabolism, controlling how your body stores and burns energy through its signaling to the thyroid, adrenals, and pancreas. When the hypothalamus becomes dysregulated by chronic stress, poor sleep, inflammation, or blood sugar instability, it defends a higher weight "set point" — causing the body to hold onto fat regardless of diet or exercise. This makes hypothalamic dysfunction an upstream root cause of stubborn weight gain.

What is a weight set point and why won't mine move?

A weight set point is the body weight your hypothalamus works to defend, calibrated over time by stress, sleep, hormones, and inflammation. When you diet, the hypothalamus perceives scarcity and responds by slowing metabolism, increasing hunger hormones, and suppressing satiety signals to return you to that set point. This is why most people regain lost weight within two to five years of conventional dieting — the set point itself was never recalibrated, only temporarily overridden.

Why do I gain weight under stress even when I'm not eating more?

Chronic stress raises cortisol, which disrupts blood sugar regulation, promotes abdominal fat storage, and signals the hypothalamus that the body is under threat. In survival mode, the hypothalamus defends fat stores and slows metabolism — so weight can increase even without any change in calorie intake. The stress chemistry, not the food, is driving the weight gain, which is why stress reduction is essential to any lasting metabolic reset.

Why do I regain weight after stopping GLP-1 medications?

GLP-1 medications work peripherally on appetite and gastric signaling, but they do not address the underlying hypothalamic dysregulation that sets your defended weight. Because the hypothalamic set point is never recalibrated, the body resumes defending its original weight once the medication stops — leading to significant regain. Long-term success requires restoring hypothalamic regulation so the set point itself lowers, rather than relying on appetite suppression alone.

How long does it take to reset your metabolism?

Genuine metabolic recalibration takes a minimum of 90 days, because the hypothalamus needs consistent signals of safety and sufficiency before it will lower its defended set point. This differs from a diet, which produces temporary suppression the body quickly corrects. A 90-day reset typically moves through three phases: stabilizing stress chemistry (days 1–30), rebuilding metabolic efficiency (days 31–60), and lowering the weight set point (days 61–90).

Why does my thyroid feel slow even though my labs are "normal"?

Under chronic stress, the body converts thyroid hormone into reverse T3, which blocks active thyroid receptors and slows metabolism at the cellular level — even when standard lab values appear normal. This means you can experience genuine symptoms of slow metabolism, such as fatigue, cold intolerance, and brain fog, while your thyroid panel looks unremarkable. Addressing the upstream hypothalamic and stress signaling often improves thyroid conversion and symptoms.

Is stubborn weight gain a willpower problem?

No. Stubborn weight gain is a signaling problem, not a willpower problem. The hypothalamus governs weight through survival mechanisms that operate below conscious control — defending its set point by slowing metabolism and increasing hunger when it perceives threat. No amount of discipline can override this system; lasting change comes from restoring hypothalamic regulation through reduced stress, balanced blood sugar, restorative sleep, and targeted nutritional support.

About the Author - Deborah Maragopoulos FNP

Known as the Hormone Queen®️, I’ve made it my mission to help everyone - no matter their age - balance their hormones, and live the energy and joy their DNA and true destiny desires. See more about me my story here...

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Last Updated: March 29, 2023