Obesity

Can being overweight affect my milk supply?

Overweight mothers are less likely to start breastfeeding. Their milk is more likely to come in late and they tend to breastfeed for shorter times. Studies suggest that excess weight affects breast development by causing inflammation and abnormal hormone levels, which interfere with the growth and development of milk tissue. It may also affect a mother’s response to suckling, reducing the milk supply over time. Being overweight may lead to other problems like type 2 diabetes, high blood pressure, and Caesarean deliveries, which can make breastfeeding more difficult. Positioning the baby at the breast may have challenges.

A) Likelihood of breastfeeding

Compared with mothers of average weight, mothers who are obese are (Achike 2021; Hashemi-Nazari 2020; Nomura 2020):

  • Less likely to start breastfeeding.
  • More likely to:
    • Breastfeed for shorter times.
    • Have their milk come in late.

The higher the degree of overweight, the more likely mothers are to have breastfeeding difficulty (Marshall 2018; Ramji 2018).

One study found that mothers who were obese before or around the time of puberty were more likely to have a low milk supply than those whose obesity developed later (Hawkins 2019).

Mothers who are overweight or obese can struggle with the impact of medical intervention during labour and delivery and doubt their ability to breastfeed. They benefit from extra support from health-care providers (Lyons 2019; Zimmerman 2019).

B) Effect of obesity on the breast

Obesity may decrease breast tissue development through inflammation or through abnormal levels of estrogen or other hormones (Brown 2014; Kamikawa et al. 2009; Olson et al. 2010). With less milk tissue, mothers make less milk.

Obesity may also affect the function of the breast. Mothers who are overweight or obese appear to produce less prolactin, the hormone that stimulates milk production, in response to the baby’s suckling (Masho 2015; Rasmussen 2004). This may result in the milk supply decreasing over time.

The negative effects of obesity on breastfeeding and breast milk production may continue even after a mother returns to a normal weight following dietary changes or weight-loss (bariatric) surgery (Gascoin 2017). Mothers who have undergone bariatric surgery are less likely to start breastfeeding and are more likely to stop early (Del Sordo 2020). Mothers who have had bariatric surgery are at risk of vitamin and other nutritional deficiencies and should be monitored by their health-care providers.

References

Achike M, Akpinar-Elci M. The Role of Maternal Prepregnancy Body Mass Index in Breastfeeding Outcomes: A Systematic Review. Breastfeed Med. 2021 Apr 27

Brown KA. Impact of obesity on mammary gland inflammation and local estrogen production. J Mammary Gland Biol Neoplasia. 2014 Jul;19(2):183-9

Chen CN, Yu HC, Chou AK. Association between Maternal Pre-pregnancy Body Mass Index and Breastfeeding Duration in Taiwan: A Population-Based Cohort Study. Nutrients. 2020 Aug 7;12(8):E2361

Del Sordo G, Botta A, Salvi S, et al. Postnatal Health in Children Born to Women After Bariatric Surgery. Obes Surg. 2020 Jun 9

Gascoin G, Gerard M, Sallé A, et al. Risk of low birth weight and micronutrient deficiencies in neonates from mothers after gastric bypass: a case control study. Surg Obes Relat Dis. 2017 Aug;13(8):1384-1391

Hashemi-Nazari SS, Hasani J, Izadi N, et al. The effect of pre-pregnancy body mass index on breastfeeding initiation, intention and duration: A systematic review and dose-response meta-analysis. Heliyon. 2020 Dec 7;6(12):e05622

Hawkins MAW, Colaizzi J, Rhoades-Kerswill S, et al. Earlier Onset of Maternal Excess Adiposity Associated with Shorter Exclusive Breastfeeding Duration. J Hum Lact. 2019 May;35(2):292-300

Kamikawa A, Ichii O, Yamaji D, et al. Diet-induced obesity disrupts ductal development in the mammary glands of nonpregnant mice. Dev Dyn. 2009 May;238(5):1092-9

Lyons S, Currie S, Peters S, et al. The perceptions and experiences of women with a body mass index ≥ 30 kg m2 who breastfeed: A meta-synthesis. Matern Child Nutr. 2019 Jul;15(3):e12813
 
Marshall NE, Lau B, Purnell JQ, et al. Impact of maternal obesity and breastfeeding intention on lactation intensity and duration. Matern Child Nutr. 2018 Oct 21:e12732
 
Masho SW, Cha S, Morris MR. Prepregnancy obesity and breastfeeding noninitiation in the United States: an examination of racial and ethnic differences. Breastfeed Med. 2015 Jun;10(5):253-62
 
Nommsen-Rivers LA, Chantry CJ, Peerson JM, et al. Delayed onset of lactogenesis among first-time mothers is related to maternal obesity and factors associated with ineffective breastfeeding. Am J Clin Nutr 2010;92:574–584
 
Nomura K, Minamizono S, Nagashima K, et al. Maternal Body Mass Index and Breastfeeding Non-Initiation and Cessation: A Quantitative Review of the Literature. Nutrients. 2020 Sep 2;12(9):E2684

Olson LK, Tan Y, Zhao Y, et al. Pubertal exposure to high fat diet causes mouse strain-dependent alterations in mammary gland development and estrogen responsiveness. Int J Obes (Lond). 2010 Sep;34(9):1415-2

Rasmussen KM, Kholhere CL. Prepregnant overweight and obesity diminish the prolactin response to suckling in the first week postpartum. Pediatrics 2004 May;113(5):e465-71
 
Ramji N, Challa S, Murphy PA. A comparison of breastfeeding rates by obesity class. J Matern Fetal Neonatal Med. 2018 Nov;31(22):3021-3026

Zimmerman E, Rodgers RF, O'Flynn J, et al. Weight-Related Concerns as Barriers to Exclusive Breastfeeding at 6 Months. J Hum Lact. 2019 May;35(2):284-291