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  • Writer's pictureBIOMILQ Team

How Stress Can Complicate Lactation

Updated: Dec 2, 2022

As scientists, we are absolutely fascinated by what our bodies and the millions of cells that we’re made of are capable of doing to keep us healthy. But, sometimes, our bodies don’t work as we might expect them to. Although the study of the intricacies of lactation is still in its infancy, recent evidence reveals that there’s a connection between mental state and lactation: increased stress hormones can actually physiologically reduce milk biosynthesis.

Mind-body connection is a wild thing, y’all.

First, a quick lesson on milk-making: prolactin is the hormone that gives mammary epithelial cells the green light to do what they do best, make milk. Prolactin is at its highest during pregnancy and after childbirth (2). When a baby latches on to the nipple, a signal is sent to the brain to release prolactin and oxytocin to trigger milk production and release — it’s simple supply and demand. This let-down reflex, or milk release, can even occur spontaneously when the baby is not even latched to the nipple from cues like hearing a baby cry or breast stimulation. While the concept of supply and demand is simple, it’s more of a complicated, delicate, and minimally understood dance when it comes to lactation.

As Sobrinho (2003) notes, there are fascinating “intersections between prolactin, psychological stress and the environment in humans” (5). Researchers found that mothers who had stressful deliveries, such as emergency c-sections or late preterm births, are more likely to have delayed onset lactation (3, 7). Tully et al. (2014) reported that “mothers who delivered by C- section are astounded when they are expected to immediately start breastfeeding without any regard to postsurgical recovery” (6) — we’re astounded too. But, maternal stress isn’t just limited to birth experience: more stressed mothers have shown lower levels of prolactin (1).

So, evidence published as recently as August of this year does suggest that stress can affect physiological or hormonal responses, which interferes with milk production and release (4). But, the exact physiological mechanism for stress-associated decreased lactation remains poorly understood.

Human lactation is relatively understudied compared to other aspects of human physiology — there are only 237 search results for “human lactation” in PubMed, compared to 26,086 results for “erectile dysfunction”. Despite the extensive global effort to develop interventions to improve breastfeeding rates, several recent studies found that many women report that they were not adequately prepared for the challenges that they might encounter (8, 9). Such interventions mostly focused on educating women about the benefits of breastfeeding rather than adequately preparing them for the diverse challenges they may experience. BIOMILQ believes that offering physiological explanations for all-too-common challenges of breastfeeding will offer new mothers comfort and empowerment during their feeding journey.

Armed with knowledge, mothers who intend to breastfeed may feel less stressed about their challenges.

For example, mothers with low milk supply may find comfort in knowing that their low supply isn’t necessarily a reflection of a lack of effort but rather a reflection of the fact that human lactation’s complexity is a neglected area of discussion and study (10). Not feeling chronically anxious about her child’s nutrition could even potentially increase a mother’s prolactin levels and thus her milk supply. Messaging around infant feeding has greater implications than we might assume — transparency about milk-making can replace the all-too-common self-perpetuating cycle created by stress, hormonal changes, and unrealistic expectations.

Everyday at BIOMILQ, we recognize the responsibility we have as scientists supported by mission-aligned investors who are 100% ‘latched-on’ to the potential of mammary biotechnology: the potential for infant health, for planetary health, and for a mom’s peace of mind.


  1. Bibi, Safia, et al. June 2021. “T3 is linked to stress-associated reduction of prolactin in lactating women.” Journal of Endocrinology.

  2. Buhimschi, Catalin S. MD. 2004. “Endocrinology of lactation.” Obstet Gynecol Clin N Am 31 963–979.

  3. Grajeda, Rubén , Rafael Pérez-Escamilla. 2002 “Stress During Labor and Delivery Is Associated with Delayed Onset of Lactation among Urban Guatemalan Women.” The Journal of Nutrition, Volume 132, Issue 10, Pg 3055–3060.

  4. Lau, C., Hurst, N., Smith, E. et al. 2007. “Ethnic/racial diversity, maternal stress, lactation and very low birthweight infants.” J Perinatol 27, 399–408.

  5. Sobrinho LG. 2003. “Prolactin, psychological stress and environment in humans: adaptation and maladaptation.: Pituitary. 6(1):35–9.

  6. Tully KP, Ball HL. 2014. “Maternal accounts of their breast-feeding intent and early challenges after caesarean childbirth.” Midwifery. 30:712–9.

  7. Zanardo, Vincenzo, et al. 2011. “Psychological distress and early lactation performance in mothers of late preterm infants.” Early Human Development.

  8. Fox R, McMullen S, Newburn M. 2015 “UK women’s experiences of breastfeeding and additional breastfeeding support: a qualitative study of Baby Café services.” BMC Pregnancy Childbirth. 15:147.

  9. Francis et al. 2020. “Vulnerable mothers’ experiences breastfeeding with an enhanced community lactation support program.” Maternal and Childhood Nutrition. 16:e12957.

  10. Boss M, Gardner H and Hartmann P. 2018. “Normal Human Lactation: closing the gap [version 1; peer review: 4 approved].” F1000Research 2018, 7(F1000 Faculty Rev):801.

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