Insulin Resistance and Low Milk Supply: What Breastfeeding Parents Need to Know
Updated: Sep 6
Written and clinically reviewed by Jennifer Gerard, MSN, APRN, FNP-C, IBCLC
Updated August 27, 2026
When milk supply remains low despite frequent breastfeeding or pumping, it is natural to wonder whether something deeper may be contributing.
Low milk supply can be frustrating—especially when you are breastfeeding or pumping frequently and still not seeing the milk production you expected.
Sometimes the problem isn't simply how often milk is removed.
Metabolic health may also influence lactation.
Insulin resistance, which is common in people with polycystic ovary syndrome (PCOS), a history of gestational diabetes, or other metabolic risk factors, has been associated with delayed lactogenesis and lower milk production in some breastfeeding parents.
Understanding that connection can help answer an important question:
Could there be a medical reason for persistent low milk supply?
Low Milk Supply Is Usually Multifactorial
Insulin resistance is only one possible contributor to persistent low milk production. Explore other medical causes of low milk supply that may be worth considering when feeding management alone does not explain the picture.
Before focusing on metabolic factors, it is important to evaluate the fundamentals of milk production and transfer, including:
Whether milk is being removed frequently and effectively
Infant latch, sucking ability, and milk transfer
Pump fit, function, frequency, and technique
Infant weight gain and diaper output
Supplementation and feeding patterns
Breast or chest surgery and glandular development
Birth complications, including postpartum hemorrhage or retained placental tissue
Thyroid, prolactin, hormonal, or other medical factors
Medications that may affect milk production
Pump output alone does not establish whether someone has low milk supply. A complete assessment considers the infant’s growth, feeding pattern, milk transfer, expressed volume, clinical history, and the parent’s goals.
For a broader overview, read Understanding Low Milk Supply: Causes, Evidence-Based Strategies & When to Seek Help.
What Is Insulin Resistance?
Insulin is a hormone that helps glucose move from the bloodstream into cells, where it can be used for energy.
With insulin resistance, cells respond less effectively to insulin. The body may compensate by producing more insulin to maintain blood glucose within the expected range. Because of this compensation, insulin resistance can be present before fasting glucose or hemoglobin A1C reaches the threshold for pre-diabetes or diabetes.
Insulin resistance is more likely in people with certain health histories or clinical findings, including:
Gestational diabetes
Prediabetes or type 2 diabetes
Polycystic ovary syndrome, or PCOS
A family history of type 2 diabetes
Metabolic syndrome
Elevated triglycerides or low HDL cholesterol
Acanthosis nigricans, which appears as darker or thickened areas of skin
A history of glucose intolerance
Certain patterns of central adiposity
Having one or more of these factors does not mean that insulin resistance is responsible for low milk supply. It does, however, provide useful context when supply remains lower than expected despite appropriate lactation support.
How Might Insulin Resistance Affect Milk Production?
The transition to milk production involves several coordinated stages.
During pregnancy, breast tissue develops and differentiates in preparation for lactation. Following delivery of the placenta, changing progesterone and prolactin levels support secretory activation—the onset of increasing milk production commonly described as the milk “coming in.”
After that transition, ongoing milk production depends heavily on frequent and effective milk removal. Hormonal and metabolic signals continue to support the energy-intensive process of producing human milk.
Research has shown that insulin-sensitive pathways become more active in mammary tissue during lactation.
Insulin appears to participate in:
Mammary gland development
Secretory differentiation during pregnancy
Secretory activation after birth
Glucose utilization within milk-producing cells
Ongoing milk synthesis
When insulin signaling is impaired, these processes may be less efficient in some individuals.
Clinical studies have also found associations between poorer metabolic health and delayed lactogenesis or persistently lower milk production. However, association does not prove that insulin resistance is the sole cause. Birth interventions, inflammation, PCOS, maternal illness, infant feeding challenges, and other factors may overlap.
The most accurate conclusion is that insulin resistance may be one contributor within a larger lactation picture.
When low supply persists despite skilled lactation support, a broader medical evaluation may help identify hormonal, metabolic, or recovery factors that have not yet been addressed. Explore virtual lactation consultations →
Signs That Metabolic Factors May Deserve a Closer Look
A metabolic evaluation may be worth discussing with a healthcare provider when persistent low milk production occurs alongside:
A history of gestational diabetes
PCOS or irregular menstrual cycles before pregnancy
Prediabetes or diabetes
Acanthosis nigricans
A strong family history of type 2 diabetes
Delayed onset of increasing milk production
Lower-than-expected production despite frequent and effective milk removal
Other symptoms or laboratory findings suggesting metabolic dysfunction
These findings are not diagnostic on their own. They are clues that may help determine whether further evaluation is appropriate. Metabolic health also fits within a broader postpartum recovery context. Learn how the five Recovery Systems™ may interact during healing, lactation, and physiologic adaptation after birth.
It is equally important not to overlook other medical contributors. Thyroid dysfunction, anemia or iron depletion, low prolactin, retained placental tissue, significant postpartum blood loss, insufficient glandular tissue, hormonal contraception, and certain medications may also affect milk production.
Read more about 10 Non-Diet-Related Medical and Physiologic Factors That May Contribute to Low Milk Supply.
What Might an Evaluation Include?
There is no single laboratory test that explains every case of low milk supply or definitively establishes that insulin resistance is causing a lactation problem.
An individualized evaluation may include:
A detailed lactation assessment
Before attributing low supply to a medical condition, the clinician should evaluate milk removal, infant transfer, feeding frequency, pumping practices, infant growth, supplementation, and the timeline of milk production.
A complete medical and reproductive history
Relevant information may include:
Gestational diabetes or abnormal glucose screening
PCOS or menstrual irregularity
Fertility challenges
Thyroid disease
Pregnancy and birth complications
Postpartum hemorrhage
Breast development during puberty and pregnancy
Breast or chest surgery
Current medications and hormonal contraception
Family history of diabetes or metabolic disease
Targeted laboratory testing
Depending on the clinical picture, a healthcare provider may consider tests such as:
Fasting plasma glucose
Hemoglobin A1C
Lipid profile
Thyroid testing
Complete blood count and ferritin
Prolactin testing when clinically indicated
Some clinicians may also consider fasting insulin or calculated measures such as HOMA-IR. These results require careful interpretation and are not, by themselves, universally accepted diagnostic tests for insulin resistance.
Testing should be selected based on history and symptoms rather than ordering a broad panel without a clear clinical question.
Does Treating Insulin Resistance Increase Milk Supply?
This is where the evidence remains limited.
Improving metabolic health is beneficial for long-term health, but it does not guarantee that milk production will increase. Lactation outcomes depend on the timing, severity, and combination of contributing factors.
Management may include individualized support for:
Consistent nourishment
Sustainable physical activity when medically appropriate postpartum
Sleep and recovery support
Glucose management
Treatment of PCOS, prediabetes, or diabetes
Medication when indicated
Continued optimization of milk removal and feeding management
Metformin is sometimes used to treat diabetes, prediabetes, or PCOS and has been studied as a potential intervention for metabolically influenced low milk production. However, current evidence does not support treating all low-supply cases with metformin. A small pilot trial found that participants with signs of insulin resistance had lower baseline milk production, but sustained improvement with metformin was limited.
Medication decisions should be based on the parent’s complete medical situation—not milk supply alone—and made with a qualified healthcare provider.
Herbal supplements also deserve caution. Some products marketed for milk supply can affect blood glucose, interact with medications, or be inappropriate for certain medical conditions.
Galactagogues should not replace an assessment of milk removal or underlying contributors.
A Recovery Systems™ Perspective
Milk production does not occur separately from the rest of postpartum physiology.
Lactation Demand is one of five interconnected Recovery Systems™:
Energy Production
Stress Adaptation
Healing & Restoration
Immune Regulation
Lactation Demand
Producing milk requires energy, glucose, nutrients, hormonal signaling, and ongoing physiological adaptation. At the same time, the postpartum body may be healing from birth, responding to interrupted sleep, adapting to stress, and managing underlying medical conditions.
This does not mean that fatigue, stress, or metabolic dysfunction automatically causes low milk supply. It means that persistent supply challenges deserve to be understood within the parent’s complete recovery picture—not reduced to a single recommendation to “eat more,” “drink more water,” or “pump harder.”
When to Seek Professional Support
Consider a comprehensive lactation or medical evaluation when:
Your baby is not gaining weight as expected
Your baby has fewer wet diapers or other signs of inadequate intake
Milk production remains low despite frequent and effective removal
Milk volume did not increase as expected after birth
You have a history of gestational diabetes, PCOS, thyroid disease, postpartum hemorrhage, breast surgery, or other relevant medical concerns
You are unsure whether the concern reflects low production, ineffective transfer, or pump performance
Feeding or pumping has become physically or emotionally overwhelming
Urgent concerns about infant hydration, lethargy, or inadequate intake should be addressed promptly with the infant’s healthcare provider.
The Bottom Line
Insulin resistance may contribute to delayed or reduced milk production in some breastfeeding parents, but it is rarely the entire explanation.
The goal is not to attach one diagnosis to every supply concern. It is to connect the dots between milk removal, infant feeding, hormonal signaling, metabolic health, birth history, breast anatomy, medications, and postpartum recovery.
When the underlying pattern becomes clearer, recommendations can become more targeted—and parents can move away from the painful assumption that low supply reflects insufficient effort.
Need Help Connecting the Dots?
If your milk supply remains low despite breastfeeding or pumping support, a comprehensive consultation can help examine the full picture.
As a Nurse Practitioner and IBCLC, I evaluate lactation mechanics alongside medical, hormonal, metabolic, and postpartum recovery factors. Together, we can identify appropriate next steps and create a plan that reflects your health history, feeding goals, and current circumstances.
Virtual consultations are available for patients physically located in Colorado, Florida, South Carolina, and Texas.
Frequently Asked Questions
Can insulin resistance cause low milk supply?
Insulin resistance has been associated with delayed lactogenesis and lower milk production in some individuals. However, low milk supply is multifactorial, and insulin resistance should not be assumed to be the sole cause without a broader lactation and medical assessment.
Can someone have insulin resistance with a normal A1C?
Yes. The body may compensate for reduced insulin sensitivity by producing more insulin, allowing glucose and A1C to remain within the expected range for a period of time. Results should be interpreted alongside clinical history and other findings.
Does PCOS always cause low milk supply?
No. Many people with PCOS produce a full milk supply. PCOS includes different hormonal and metabolic patterns, and its effect on lactation varies considerably.
Will changing my diet increase my milk supply?
Nutrition supports overall health and lactation, but there is no single food or diet that reliably corrects low milk supply. When production remains low, effective milk removal and potential infant, anatomical, hormonal, or medical contributors should be evaluated.
Should I take metformin to increase milk supply?
Metformin is not an established general treatment for low milk supply. It may be prescribed for an underlying metabolic condition, but medication decisions should be individualized with a qualified healthcare provider.
What testing should I request?
Testing depends on your history, symptoms, birth experience, and lactation pattern. A targeted evaluation is generally more useful than requesting the same broad laboratory panel for everyone.
Evidence-Informed References
Nommsen-Rivers, L. A. (2016). Does insulin explain the relation between maternal obesity and poor lactation outcomes? An overview of the literature. Advances in Nutrition, 7(2), 407–414.
Nommsen-Rivers, L. A., Thompson, A., Riddle, S., Ward, L., Wagner, E., & King, E. (2019). Feasibility and acceptability of metformin to augment low milk supply: A pilot randomized controlled trial. Journal of Human Lactation, 35(2), 261–271.
Nommsen-Rivers, L. A., et al. (2022). Measures of maternal metabolic health as predictors of severely low milk production. Breastfeeding Medicine, 17(5), 415–424.
This article is for educational purposes and does not replace individualized medical advice, diagnosis, or treatment.
Jennifer Gerard, MSN, APRN, FNP, IBCLC
Jennifer Gerard, APRN, FNP, IBCLC is a Family Nurse Practitioner and International Board Certified Lactation Consultant specializing in breastfeeding medicine and complex lactation care through virtual consultations.
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