Understanding What Decreases Breast Milk Supply

Posted on April 09, 2026

Introduction
The Science of Supply and Demand
Physical and Health-Related Factors
Medications and Herbs to Watch Out For
Lifestyle Factors and the Stress Response
Dietary Habits and Nourishment
Management Mistakes: The "Hidden" Supply Killers
Practical Scenarios: Real-World Challenges
How Milky Mama Can Help Protect Your Supply
When to Seek Professional Help
Final Thoughts on Maintaining Your Supply
FAQ

Introduction

You are sitting on the couch, the rhythmic sound of your breast pump providing a steady background noise to the quiet of the night. You look down at the collection bottle, expecting to see the usual amount, but instead, you see significantly less than yesterday. That immediate tightening in your chest—the "is something wrong?" panic—is a feeling so many of us have experienced. Whether you are exclusively nursing, pumping, or doing a bit of both, your milk supply often feels like a direct reflection of your ability to provide for your little one. But here is the truth we want you to hold onto: milk supply is dynamic, and while it is normal for it to fluctuate, understanding what decreases breast milk supply is the first step in reclaiming your confidence and your flow.

At Milky Mama, we believe that breastfeeding is one of the most natural things in the world, yet it doesn’t always come naturally. It’s a skill that both you and your baby are learning together. We also know that for many parents, especially Black breastfeeding moms who often face systemic barriers to support, having clear, evidence-based information is vital. Our mission, led by our founder Krystal Duhaney, RN, BSN, IBCLC, is to ensure you never feel alone in this journey. In this post, we are going to dive deep into the biological, environmental, and lifestyle factors that can cause your supply to dip. We will explore how your body creates milk, the hidden "supply killers" in your medicine cabinet or kitchen, and practical steps you can take to get back on track.

Every drop counts, and so does your well-being. By the end of this article, you will have a comprehensive understanding of how to protect your milk supply and where to turn when you need a little extra boost.

The Science of Supply and Demand

To understand what decreases breast milk supply, we first have to understand how your body makes milk in the first place. Breasts were literally created to feed human babies, and the process is a marvel of biological engineering.

In the first few days after birth, your milk supply is largely driven by hormones. The delivery of the placenta triggers a drop in progesterone and a rise in prolactin, which tells your body to move from colostrum to "mature" milk. However, after those first few weeks, your supply shifts from being hormonally driven to being demand-driven. This is the "Supply and Demand" phase.

Your body monitors how much milk is removed from the breast. When the breast is emptied, it sends a signal to your brain to make more. When milk sits in the breast for long periods, a protein called Feedback Inhibitor of Lactation (FIL) builds up. This protein tells your body, "Hey, we have plenty of milk sitting here; slow down production." Therefore, the most common thing that decreases milk supply is actually a lack of frequent and effective milk removal.

Physical and Health-Related Factors

Sometimes, the factors affecting your supply are internal. Your body is a complex system, and when one part is struggling, it can impact your lactation.

Hormonal Imbalances

Because breastfeeding is so closely tied to your endocrine system, hormonal shifts can have a major impact.

Thyroid Issues: Both hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can interfere with milk production. If you are feeling unusually fatigued, experiencing hair loss, or having trouble with your supply despite frequent nursing, it may be worth having your thyroid levels checked.
PCOS (Polycystic Ovary Syndrome): This condition can affect the development of mammary tissue during pregnancy and the hormonal balance required for a robust milk supply.
Retained Placenta: Even a tiny piece of the placenta remaining in the uterus after birth can keep progesterone levels high enough to prevent your milk from fully "coming in."

A New Pregnancy

If you find your supply dropping suddenly while you are still nursing an older baby, you might want to take a pregnancy test. Pregnancy causes a massive shift in hormones that almost always results in a decrease in milk supply, usually around the fourth or fifth month. While many people continue to nurse through pregnancy (tandem nursing), it is important to be aware that the supply dip is biological and usually cannot be fully reversed until after the new baby arrives.

Illness and Dehydration

When you are sick, your body diverts energy to your immune system to help you recover. If you have a fever, you are also losing fluids at a faster rate. Dehydration is a significant factor in what decreases breast milk supply. While we often tell moms to "drink to thirst," when you are ill, you may need to be more intentional about your fluid intake.

Pro Tip: If you're struggling to stay hydrated while sick, our Lactation LeMOOnade™ or Milky Melon™ are excellent ways to support hydration while also providing lactation-supporting ingredients.

Medications and Herbs to Watch Out For

You might be surprised to learn that common items in your medicine cabinet or spice rack could be the culprits behind a supply dip.

Antihistamines and Decongestants

During allergy season or when a cold strikes, it is common to reach for a decongestant. However, medications containing pseudoephedrine (often found in "D" versions of cold meds) are designed to dry up secretions. Unfortunately, they don't just target your sinuses; they can also dry up your milk supply. Even a single dose can cause a noticeable decrease for some moms. Antihistamines can have a similar, though usually milder, effect.

Certain Hormonal Contraceptives

While many parents are told that the "mini-pill" (progestin-only) is safe for breastfeeding, methods containing estrogen (like the combined pill, the patch, or the ring) are well-known to decrease milk supply. We always recommend talking to your healthcare provider about non-hormonal options or progestin-only methods if you are concerned about your supply.

Herbs Used for Drying Up

In the culinary world, herbs like sage, peppermint, parsley, and rosemary are staples. However, in medicinal amounts, these can actually be used to help wean a baby or dry up an oversupply. If you are eating a large amount of peppermint bark during the holidays or drinking a lot of sage tea, you might notice a dip. (Note: A peppermint latte or a garnish of parsley is usually fine; it's the concentrated amounts that pose a risk).

Lifestyle Factors and the Stress Response

We live in a world that often expects parents to "bounce back" and do it all. But the stress of modern life can be a major factor in what decreases breast milk supply.

The Cortisol Connection

When you are stressed, your body produces cortisol and adrenaline. These hormones can inhibit the "let-down reflex," which is governed by oxytocin (the "love hormone"). If your milk isn't letting down effectively, it isn't being removed from the breast, which—as we learned earlier—tells your body to make less milk. Stress doesn't necessarily stop your body from making milk, but it can stop the milk from leaving the breast, which eventually leads to a decrease in production.

Lack of Sleep and Self-Care

While "sleep when the baby sleeps" is often unrealistic advice, chronic, severe sleep deprivation can take a toll on your physical health and your supply. Your body needs energy to produce milk. If you are running on empty, your milk supply might reflect that.

Returning to Work

For many of us, returning to work is a major turning point. The transition from nursing on demand to using a breast pump can be difficult. Common issues include:

Poorly fitting pump flanges: If your flanges are the wrong size, the pump cannot effectively remove milk.
Inadequate pumping breaks: Missing even one session during an 8-hour shift can signal to your body that it needs to slow down.
Stress of the workplace: Being away from your baby and dealing with work deadlines can make it harder to get a good let-down while pumping.

If you are preparing for this transition, we highly recommend taking our Breastfeeding 101 class or a specific back-to-work course to help you navigate these challenges.

Dietary Habits and Nourishment

We often hear that you don't need a "perfect" diet to breastfeed, and that is true! Your body will prioritize your baby’s nutrition even if you aren’t eating perfectly. However, severe calorie restriction can absolutely lead to a decrease in supply.

Many moms feel pressure to lose the "baby weight" quickly. If you drop your calorie intake too low or start an intense exercise program too soon without increasing your caloric intake to match the burn, your supply may suffer. Breastfeeding typically burns an extra 300 to 500 calories a day. Your body needs that fuel!

Rather than focusing on restriction, focus on nourishment. Incorporating nutrient-dense snacks like our Oatmeal Chocolate Chip Cookies or Emergency Brownies can provide your body with the energy it needs while also utilizing traditional galactagogues like oats and flaxseed.

Management Mistakes: The "Hidden" Supply Killers

Sometimes, what decreases breast milk supply isn't an external factor, but rather a misunderstanding of breastfeeding management.

Supplementing Without Pumping

If you give your baby a bottle of formula because you are worried they are still hungry, but you don't pump to "replace" that feeding, your body doesn't know the baby ate. It thinks the baby didn't need that milk, so it stops making it for that time of day. This is often called the "top-up trap." If you must supplement, always try to pump for 15–20 minutes to maintain that demand signal.

Scheduled Feedings vs. On-Demand Feedings

The idea of getting a baby on a strict three-hour schedule is popular in some parenting circles, but it can be detrimental to milk supply, especially in the early months. Every baby’s stomach capacity and every mom’s breast storage capacity are different. Some babies need to eat every two hours to get what they need. By forcing a schedule, you might be missing the cues that your baby needs to remove milk, leading to a decrease over time.

Pacifier Overuse

Pacifiers are a great tool for soothing, but if they are used to delay feedings or if a baby satisfies their "sucking urge" on a pacifier instead of the breast, it can lead to fewer nursing sessions and a lower supply.

Practical Scenarios: Real-World Challenges

Let’s look at how these factors might show up in your daily life.

Scenario 1: The "Hectic Morning" Trap

Imagine Sarah, a mom of two. Her toddler is having a tantrum, she’s trying to get out the door, and she realizes she hasn’t had a sip of water or a bite to eat by 11:00 AM. She skips her mid-morning nursing session and gives the baby a quick bottle of expressed milk to save time. By the afternoon, Sarah feels "empty." In this case, the combination of stress, dehydration, skipped milk removal, and lack of calories is all working together to decrease her supply.

The Solution: Sarah could benefit from "habit stacking." Drinking a bottle of Pumpin Punch™ while she helps her toddler get dressed ensures she is hydrated. Keeping a bag of Salted Caramel Cookies in her car or diaper bag gives her a quick, lactation-supportive snack when she can't sit down for a meal.

Scenario 2: The Return to the Office

Maya just went back to her job as a teacher. She only has 20 minutes for lunch, and the "lactation room" is a long walk from her classroom. She finds herself rushing her pumping sessions and not getting a full empty. After a week, she notices she is pumping two ounces less than she used to.

The Solution: Maya might need to look into a more powerful herbal supplement to support her during this transition. Pumping Queen™ or Pump Hero™ are specifically formulated for those who are pumping frequently. She may also want to schedule a virtual lactation consultation to discuss hands-on pumping techniques that can help her empty her breasts more quickly.

How Milky Mama Can Help Protect Your Supply

We created our products because we know that sometimes you need a little extra support to bridge the gap. Whether you are dealing with a temporary dip due to illness or navigating a long-term challenge like returning to work, we have options designed with you in mind.

Targeted Herbal Supplements

Our herbal supplements are crafted to support different needs without the use of controversial ingredients.

Lady Leche™: Designed to support milk flow and volume.
Milk Goddess™: A favorite for many moms looking for a comprehensive boost.
Dairy Duchess™: Formulated for those looking to enrich their milk.

This product is not intended to diagnose, treat, cure, or prevent any disease. Consult with your healthcare provider for medical advice.

Delicious and Functional Treats

Eating for your milk supply shouldn't feel like a chore. Our Lactation Snacks are made with ingredients like oats, brewers yeast, and flaxseed. From our Peanut Butter Chocolate Chip Cookies to our Fruit Sampler, there is something for every palate.

Education and Community

We are more than just a product company; we are a support system. If you aren't sure why your supply is dipping, our online breastfeeding classes can help you troubleshoot. You can also join The Official Milky Mama Lactation Support Group on Facebook to connect with thousands of other parents who are on the same journey.

When to Seek Professional Help

While many supply issues can be addressed with lifestyle changes and lactation support products, some situations require the expertise of a professional. You should reach out to an International Board Certified Lactation Consultant (IBCLC) or your healthcare provider if:

Your baby is not gaining weight or is losing weight.
Your baby is having fewer than six heavy wet diapers in a 24-hour period (after the first week).
Breastfeeding is consistently painful (a poor latch can decrease milk removal and supply).
You suspect a medical issue like a thyroid imbalance or PCOS.
You are feeling overwhelmed, anxious, or depressed. Your mental health is just as important as your milk supply.

Remember, seeking help isn't a sign of failure; it's a sign of a proactive parent doing what’s best for their family.

Final Thoughts on Maintaining Your Supply

Understanding what decreases breast milk supply is empowering. It takes the "mystery" out of those low-pumping days and gives you a roadmap for how to respond. Whether it's adding a session of "power pumping," reaching for a bottle of Pumpin Punch™, or finally making that appointment for a virtual consultation, you have the tools to protect your breastfeeding journey.

Breastfeeding is a beautiful, challenging, and deeply personal experience. There will be days when it feels easy and days when you feel like throwing in the towel. Through it all, know that you are doing an amazing job. Your worth as a mother is not measured in ounces, but the love and care you provide for your baby are priceless. Every drop counts, but so do you.

FAQ

1. Does caffeine decrease milk supply?

For most people, a moderate amount of caffeine (about 1-2 cups of coffee per day) does not decrease milk supply. However, caffeine is a diuretic, so if you are consuming a lot of it and not counteracting it with water, dehydration could lead to a dip. Additionally, some babies are sensitive to caffeine, which might make them fussy at the breast, leading to shorter nursing sessions.

2. Can my period make my milk supply drop?

Yes, many people notice a temporary dip in supply during ovulation and in the days leading up to their period. This is due to a drop in blood calcium levels and shifts in estrogen and progesterone. Typically, your supply will bounce back once your period starts. Some moms find that taking a calcium and magnesium supplement can help minimize this dip.

3. Will my supply ever come back if it has decreased?

In many cases, yes! Because supply is based on demand, increasing the frequency of milk removal (through power pumping or extra nursing sessions) can signal your body to ramp up production. Using supportive tools like our Milky Maiden™ or Lady Leche™ can also provide that extra boost while you work on increasing demand.