Understanding Low Milk Supply: Causes, Signs, and Evidence-Based Solutions (Part 1)

Introduction

Early in the journey of parenthood, many breastfeeding parents worry that they are not making enough milk to nourish their baby. While concerns about low milk supply are not uncommon, true low milk supply itself is much less common than perceived low milk supply. Many normal newborn feeding behaviors, such as frequent nursing, cluster feeding, or changes in breast fullness, can lead parents to question if they are making enough milk for their baby.

Understanding the difference between perceived low supply and true low milk supply can help families recognize what is normal, identify potential challenges early, and seek appropriate support when needed. With accurate information and timely guidance, most breastfeeding concerns can be addressed, helping parents meet their infant feeding goals with confidence and success.

How Milk Production Works

Brief Overview

During pregnancy a mother’s body undergoes remarkable hormonal changes to prepare for breastfeeding and childbirth. Hormones such as estrogen and progesterone stimulate the growth and development of milk-producing structures within the breast, while prolactin prepares the breasts to produce milk.

After birth, the delivery of the placenta causes progesterone levels to drop rapidly. This hormonal shift signals the body to begin producing larger amounts of milk over the next few days, a process known as lactogenesis II, or when a mother’s milk “comes in.” At the same time, the hormone oxytocin is released. Oxytocin causes the uterus to contract, helping reduce bleeding after delivery, and also triggers the “let-down” reflex, allowing milk to flow from the breast to the baby.

When babies are placed skin-to-skin immediately after birth, many will instinctively use their sense of smell, touch, and natural feeding reflexes to find the breast and begin nursing. Their first food is colostrum, often called liquid gold. Although produced in small amounts, colostrum is perfectly designed for a newborn. It is rich in protein, antibodies, immune cells, and growth factors that help protect the baby from infection while supporting the development of their immature digestive system.

In the first day of life, a newborn’s stomach is only about the size of a marble, so these small volumes of colostrum are exactly what most babies need. As babies grow, their stomach capacity increases, and frequent breastfeeding signals the mother’s body to produce more milk.

Breast milk production works on a simple supply-and-demand system; the best way to make more milk is to remove more milk. Every time a baby nurses or milk is removed through pumping, the breast receives the message to continue making milk. Frequent, effective milk removal during the first several weeks after birth is one of the most important factors in establishing a healthy milk supply.

If feedings at the breast are regularly replaced with formula and milk is not removed through pumping or breastfeeding, the breasts receive less stimulation, which can lead to a decrease in milk production over time. For this reason, mothers who wish to breastfeed are encouraged to nurse frequently during the early weeks while their milk supply is being established. When supplementation is medically necessary or chosen by the family, pumping during missed breastfeeding sessions can help protect and maintain milk supply.

What Is Low Milk Supply?

Understanding the designation and defining the difference between Low Milk Supply and Perceived Low Milk Supply

Low milk supply is a common concern among mothers who wish to breastfeed, yet defining what constitutes a “low” milk supply can be challenging because milk production varies considerably among mothers and is influenced by both maternal and infant factors. Importantly, a mother’s perception that she is not producing enough milk does not necessarily indicate true physiological low milk supply.

A 2025 study, Defining Low Milk Supply: A Data-Driven Diagnostic Framework and Risk Factor Analysis for Breastfeeding Women, sought to establish a more objective approach to identifying low milk production by examining patterns of milk output, formula supplementation, and infant growth. Researchers identified four distinct milk-production classes. Classes 1 and 2 represented higher milk-production profiles, characterized by minimal formula supplementation or milk production that met or exceeded the infant’s needs, along with adequate infant growth. Classes 3 and 4 represented profiles associated with greater concern for insufficient milk production and provided insight into maternal factors that may increase the risk of reduced milk supply.

Several maternal characteristics were associated with these lower-production profiles, including gestational diabetes, advanced maternal age, and minimal breast growth during pregnancy. These findings are important because they highlight that milk supply is not simply a matter of maternal effort or feeding frequency; underlying maternal physiology and pregnancy-related factors can also influence lactation.

Historically, researchers have used a threshold of approximately 600 mL of expressed milk over a 24-hour period as an indicator of low milk production. This is equivalent to approximately 20 ounces per day. The 2025 study proposed a higher data-derived threshold of approximately 708 mL per 24 hours, or about 23–24 ounces per day, at which concerns about inadequate milk production became more apparent within the study population. This represents an important shift in how researchers may conceptualize low milk supply.

However, these numbers should not be interpreted as a universal cutoff for breastfeeding success. Milk volume alone does not determine whether an infant is receiving enough milk. Direct breastfeeding makes precise measurement of intake difficult, and factors such as effective milk transfer, feeding frequency, infant weight gain, diaper output, supplementation, and maternal and infant health must be considered together. A mother producing less than 708 mL per day may still be meeting her infant’s needs, particularly when the infant is growing appropriately and transferring milk effectively.

The significance of these findings is that they move the conversation about low milk supply beyond maternal perception and toward a more objective understanding of true insufficient milk production and the factors that may contribute to it. Identifying maternal risk factors earlier may allow healthcare providers and lactation professionals to provide targeted support before concerns about milk supply become barriers to continued breastfeeding.

Perceived Low Milk Supply

Perceived low milk supply, on the other hand, is a common concern among mothers who are early in their breastfeeding or parenting journey. Many parents may not yet be familiar with the normal behaviors and cues that indicate effective breastfeeding and adequate infant intake. As a result, normal variations in infant feeding behavior or changes in the mother’s breasts can sometimes be misinterpreted as signs of insufficient milk production.

Common concerns include:

• Baby wants to nurse frequently. Frequent breastfeeding can lead parents to believe that their baby is still hungry or is not transferring enough milk. However, newborns commonly breastfeed 8–12 times or more per 24 hours, and periods of increased feeding are normal.
• Breasts feel softer after the first few weeks. Many mothers expect their breasts to remain firm, full, or tight as their milk supply increases. As lactation becomes established, however, the breasts often become softer as milk production begins to regulate according to the infant’s needs. Softer breasts do not necessarily indicate a decrease in milk supply.
• Pumping output seems low. The amount of milk obtained with a breast pump does not necessarily reflect a mother’s total milk production or the amount her infant can transfer directly at the breast. Pumping technique, pump fit, timing, stress, and how recently the baby was fed can all influence expressed milk volume.
• Baby is cluster feeding. Cluster feeding refers to periods when an infant wants to breastfeed repeatedly over a short period of time. This can occur during normal developmental periods and growth spurts and may also provide comfort and regulation. Cluster feeding alone is not evidence of an inadequate milk supply.

These behaviors are often normal parts of breastfeeding and do not, by themselves, indicate low milk supply. Instead of relying solely on how frequently a baby nurses, how the breasts feel, or how much milk is expressed during pumping, parents can look for more reliable indicators of adequate intake, including:

• appropriate infant weight gain
• adequate wet and soiled diapers
• audible swallowing during feeds
• effective milk transfer
• and a baby who appears satisfied after many feedings.

When concerns persist, evaluation by a pediatric healthcare provider or lactation professional can help distinguish perceived low milk supply from true insufficient milk production.

Signs That Baby May Not Be Getting Enough Milk

Infant Signs

There are several key indicators that can help parents and healthcare providers assess whether a baby is feeding effectively and receiving adequate breast milk. While no single sign can determine milk intake on its own, infant weight patterns, diaper output, swallowing during feeds, hydration, and overall feeding behavior can provide valuable information about breastfeeding effectiveness.

• Infant weight gain and weight loss
  • Some weight loss after birth is expected as newborns adjust to life outside the womb. However, the degree of weight loss and the infant’s subsequent weight trajectory are important indicators of adequate intake. Many healthy newborns lose approximately 5–10% of their birth weight during the first several days after delivery and typically begin regaining weight once mature milk production increases. Most infants are expected to return to their birth weight by approximately 10–14 days of age, although individual circumstances can vary.
  • Weight loss approaching or exceeding 10%, failure to begin gaining weight, or failure to regain birth weight within the expected timeframe should prompt further evaluation of feeding effectiveness, milk transfer, and potential medical causes. This should be mentioned to a baby’s pediatrician so that appropriate referrals to professionals, such as an International Board Certified Lactation Consultant (IBCLC) or a gastroenterologist, can be made for further evaluation.
• Wet diaper output
  • Urine output generally increases as milk intake increases during the first several days of life. A general pattern to expect is:
    • Day 1: At least 1 wet diaper
    • Day 2: At least 2 wet diapers
    • Day 3: At least 3 wet diapers
    • Day 4: Approximately 4–5 wet diapers
    • Day 5 and beyond: Approximately 6 or more wet diapers per day
• Stool patterns
  • Newborn stool also changes as milk intake increases:
    • Days 1–2: Sticky, dark, tar-like stools called meconium
    • Days 3–4: Transitional stools that become softer and change from dark green toward greenish-brown or yellow
    • Around day 5 and beyond: Stools generally become yellow, looser, and seedy. Breastfed infants may have several stools per day, particularly during the early weeks.
• Persistent or worsening jaundice
  • Jaundice causes a yellowing of the skin and eyes due to elevated levels of bilirubin, a substance produced when red blood cells are broken down. Newborn jaundice is common, and the liver becomes increasingly effective at processing and eliminating bilirubin as the baby matures.
    • Bilirubin is a waste product that forms as the body breaks down old red blood cells. This can build up in a newborn, as their liver is still maturing and not yet able to remove waste from their system.
  • However, inadequate milk intake can contribute to or worsen jaundice, particularly when insufficient milk transfer leads to fewer bowel movements and reduced bilirubin elimination. Effective breastfeeding and adequate milk intake can therefore play an important role in preventing or managing feeding-related jaundice. Persistent, worsening, or early-onset jaundice should always be evaluated by the infant’s healthcare provider.
• Sleepiness during feeds
  • Newborns naturally sleep frequently, but excessive sleepiness during breastfeeding can make it difficult for a baby to feed effectively. A baby who consistently falls asleep shortly after beginning a feeding, rarely demonstrates active sucking and swallowing, or is difficult to wake for feeds, may need further assessment. Any concerns should be addressed with the infant’s healthcare provider first. From there, a pediatrician can make appropriate referrals to supportive people such as gastroenterologists, IBCLCs or feeding therapists.
• Difficulty maintaining a latch
  • An effective latch allows the infant to take in a substantial portion of the areola and breast tissue rather than simply grasping the nipple. A shallow latch, in which the baby primarily takes the nipple into the mouth, can cause maternal nipple pain and may interfere with effective milk transfer.Parents may notice signs of effective feeding when the baby demonstrates a deep latch. To encourage a deep latch, position the baby:
    • Nose-to-nipple and tummy-to-tummy.This will encourage the baby to open their mouth wide before bringing them to the breast.The infant should take in not only the nipple but also a good portion of the surrounding areola.Once latched, the baby’s lips should be flanged outward, sometimes described as “duck lips,” rather than tucked inward.
  • Effective feeding is typically characterized by rhythmic sucking, periodic pauses to swallow, and a deep latch throughout the feeding. Parents may also hear or see the baby swallowing, which is a particularly helpful sign that milk is being transferred. A deep, comfortable latch, combined with active sucking and swallowing, can reassure you that the baby is effectively removing milk from the breast.
• Signs of dehydration
  • Inadequate milk intake can contribute to dehydration in newborns and young infants. Because babies have small fluid reserves, recognizing potential signs of dehydration and seeking timely support and evaluation is important. Potential warning signs include:
    • Fewer wet diapers than expected for the baby’s age (see adequate ouput numbers above)
    • Very concentrated or dark urine
    • Dry mouth or lips
    • Lack of tears when crying
    • Excessive sleepiness or difficulty waking
    • A sunken soft spot on the top of the head (fontanelle)
    • Poor feeding or difficulty maintaining feeds
    • A weak suck or decreased interest in feeding

Maternal Signs

While changes in breast fullness and milk production/expression can vary considerably amongst mothers, certain maternal signs may warrant additional assessment of milk production, milk removal, or breastfeeding technique. These signs do not necessarily indicate or confirm that low milk supply is a culprit to breastfeeding challenges, but they can be important pieces of a greater picture that should be evaluated and considered by a qualified, licensed breastfeeding expert, such as an IBCLC, with considerations from the mother and infants’ healthcare providers as needed.

• Delayed onset of mature milk
  • Milk volume typically begins to increase substantially around 2-5 days after birth, as mom and baby establish a rhythm of latching and find comfort in breastfeeding. A delay in milk production, or a noticeable delay in the expected increase in production, could warrant evaluation by lactation support, particularly when infant weight gain is poor or absent, and diaper output is inadequate.
• Little breast fullness after birth
  • Some mothers notice little changes in their breasts as milk production increases, while breast fullness itself is not a reliable indicator of milk output and supply. Minimal changes in the breasts, combined with other maternal or infant factors, could warrant further evaluation or assessment.
• Minimal milk expressed after effective pumping
  • Evidence shows that babies are more effective at removing milk from the breast than pumping alone. However, for some mothers, pumping may be a necessary tool to stimulate milk production or increase their supply if their infant is unable to suckle at the breast. However, if latching the baby to the breast and expressing milk with a pump do not show an increase in breastmilk output, it may be beneficial to evaluate pumping tools, such as the pump flange size, suction level, or pumping time. It is important to note that pumping output alone does not determine a mother’s total milk supply, especially if combined with active breastfeeding.
• Ongoing breast pain or nipple trauma
  • Persistent nipple pain, cracking, bleeding, or other breast discomfort can be associated with an ineffective or shallow latch, poor positioning, or other breastfeeding challenges. Ongoing pain may interfere with effective milk removal, a mother’s confidence in her ability to breastfeed, and can contribute to stress, as well as early weaning. It is important to note that breastfeeding should not hurt and should not be just tolerated by a mother. It is a beautiful expression of care for one’s baby, one that should be comfortable and free of distress. If pain, nipple trauma, or overwhelming feelings around breastfeeding are at the forefront of a mother’s mind, she must seek support.
    • Support can come from:
      • Certified Lactation Counselors (CLC)
        • You can find a CLC near you by visiting the Academy of Lactation Policy and Practice’s website.
      • International Board-Certified Lactation Consultant (IBCLC)
        • You can find an IBCLC near you by visiting the International Lactation Consultant Association
      • Support Groups:
        • La Leche League International
        • South Carolina Breastfeeding Coalition
        • Postpartum Support International

Conclusion

Low milk supply is a complex part of a mom and baby’s breastfeeding journey. While true, insufficient milk production can occur and may be influenced by maternal, infant, hormonal, metabolic, or other medical factors, it is important to distinguish between perceived low milk supply and true low milk supply. Many of the concerns that cause mothers to question their milk supply include frequent nursing, cluster feeding, softer breasts, and low pumping outputs. These are often part of the normal rhythm of breastfeeding during periods when your baby is adjusting to life outside the womb and getting acclimated to feeding, either by latching or by bottle. They do not necessarily indicate that a baby is not getting sufficient nutrition or that the baby is not adequately transferring milk.

At the same time, parents should be aware of the need for additional support. Infant weight gain or loss, wet and dirty diaper output, effective milk transfer, audible swallowing during feeds, hydration, and overall feeding behaviors provide licensed lactation support professionals with invaluable information when evaluating whether a baby is receiving adequate milk. Maternal signs may include a delay in milk production, persistent nipple pain/trauma, and difficulty increasing milk output despite effective milk removal strategies.

Most importantly, breastfeeding mothers should not align their breastfeeding challenges as a reflection of their commitment, efforts, or ability to provide for their babies. Lactation is a biological process influenced by many factors, and some mothers may require additional support to establish or maintain their milk supply. Early identification of potential issues and prompt expression of concerns can help families and supportive persons understand what is happening and how to address potentially modifiable barriers. This can help families make informed decisions about infant feeding.

Every breastfeeding journey is unique to the mother and baby. The goal should not be to measure success by ounces alone, but to ensure that baby is fed, growing, hydrated, and thriving while the mother also feels supported, confident, empowered, and cared for throughout the process. When parents have accurate information and access to compassionate, evidence-based care and support, they are better equipped to navigate concerns about milk supply with confidence rather than fear.

Join us for Ask a CLC

Ask a CLC is a supportive program that connects parents with certified lactation counselors for guidance, education, and resources to address infant-feeding concerns. Ask a CLC is hosted on the last Thursday of each month. Register to join Ask a CLC here.

References

• Cleveland Clinic. (2021). Lactation. https://my.clevelandclinic.org/health/body/22201-lactation
• Jin, X., Lai, C., Perrella, S., Gridneva, Z., McEachran, J., Hassan, G., Taylor, N., & Geddes, D. (2025). Defining Low Milk Supply: A Data-Driven Diagnostic Framework and Risk Factor Analysis for Breastfeeding Women. Nutrients, 17(22), 3524. https://doi.org/10.3390/nu17223524
• La Leche League Internationa, USA. (2022). Low milk supply. https://lllusa.org/low-milk-supply/
• Office on Womens Health. (2025). Making breastmilk. https://womenshealth.gov/breastfeeding/learning-breastfeed/making-breastmilk#10
• WIC Breastfeeding Support, & United States Department of Agriculture (USDA). How much milk your baby needs. https://wicbreastfeeding.fns.usda.gov/how-much-milk-your-baby-needs
• WIC Breastfeeding Support, & United States Department of Agriculture (USDA). Low milk supply. https://wicbreastfeeding.fns.usda.gov/low-milk-supply

Authors

• Julianna Lyle, Rural Health and Nutrition Extension Agent, Anderson & Abbeville Counties

Reviewed By

• Michelle Altman, Extension Associate, Rural Health and Nutrition
• Melissa Bales, Extension Associate, Rural Health and Nutrition
• Ellie Lane, Extension Associate, Rural Health and Nutrition