Time to milk ‘coming in’ – Effective initiation results

Time to milk ‘coming in’ is an indicator for efficacy of interventions to support effective initiation. When it occurs within 72 h post-birth, it is an important predictor of milk volume adequacy at four weeks.

Critical time period of time to milk coming 72 hours after birth.

What is time to milk ‘coming in'?

Time to milk ‘coming in’ is the time after birth at which secretory activation occurs.1,2

Milk ‘coming in’ (secretory activation) normally occurs between 24 – 72 hours after delivery of the placenta.3-5

Secretory activation can be indicated by:

  • Three consecutive expression volumes of 20 ml or more from both breasts (combined) for exclusively pumping mothers.6
  • Physiological markers, such as a feeling of breast fullness for mothers breastfeeding and pumping.7

Why is time to milk ‘coming in’ important?

Delayed secretory activation (>72 hours after birth) is linked to increased risk of persistent low milk volumes and a shortened duration of lactation.3,8

Women experiencing delayed secretory activation are 60% more likely to stop breastfeeding at 4 weeks.8

Milk ‘coming in’ is a one-time event that is critical to continued breast milk synthesis.9

Risk factors for delayed secretory activation identified pre and perinatally include:

  • primigravida3,7
  • age of mother7
  • preterm birth7,10
  • caesarean section11
  • high body mass index (>30)3,12
  • high levels of perinatal pain and stress4,13,14
  • postpartum haemorrhage15
  • mother – infant separation16-19
  • delayed first breastfeeding episode4
  • low frequency of breastfeeding/expressing7,8

How to optimise time to milk ‘coming in’

Develop/revise breastfeeding and expression protocols in order to

  • Identify women pre and perinatally who have at-risk factors for delayed milk ’coming in‘
  • Provide at-risk women education on the milk journey and the importance of effective initiation: time to first expression, frequency of pumping, using INITIATE breast pump software, double pumping and correctly fitted breast shields.
  • Implement and support women to
    • express early within 3 hours of birth20,21
    • mothers express 8 or more time in 24 hours20,21
    • stimulate and express with INITIATE breast pump  software6,22,23
  • Provide mothers with a pumping log to track
    • daily expressions and milk volumes
    • onset of secretory activation -indicated by 3 consecutive expressions >20 ml from both breasts combined
  • Support regular staff education on the importance of the milk production journey
  • Ensure staff understand the consequences of a delay in secretory activation and are able to provide increased lactation support to mothers with risk factors


How to monitor time to milk ‘coming in’

• Track the percentage of mothers who have their milk ‘come in’ within 72 hours after birth.

• Identify mothers with delayed (>72 hours) milk ‘coming in’


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2 Hoban R et al. Human milk biomarkers of secretory activation in breast pump-dependent mothers of premature infants. Breastfeed Med. 2018; 13(5):352–360.

3 Nommsen-Rivers LA 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(3):574–584.

4 Dewey KG et al. Risk factors for suboptimal infant breastfeeding behavior, delayed onset of lactation, and excess neonatal weight loss. Pediatrics. 2003; 112(3):607–619.

5 Boss M et al. Normal human lactation: Closing the gap. F1000Res. 2018; 7.

6 Meier PP et al. Breast pump suction patterns that mimic the human infant during breastfeeding: greater milk output in less time spent pumping for breast pump-dependent mothers with premature infants. J Perinatol. 2012; 32(2):103–110.

7 Hurst NM. Recognizing and treating delayed or failed lactogenesis II. J Midwifery Womens Health. 2007; 52(6):588–594.

8 Brownell E et al. Delayed onset lactogenesis II predicts the cessation of any or exclusive breastfeeding. J Pediatr. 2012; 161(4):608–614.

9 Meier PP et al. Which breast pump for which mother: An evidence-based approach to individualizing breast pump technology. J Perinatol. 2016; 36(7):493–499.

10 Parker LA et al. Indicators of Secretory Activation in Mothers of Preterm Very Low Birth Weight Infants. J Hum Lact. 2020:890334420980424.

11 Hobbs AJ et al. The impact of caesarean section on breastfeeding initiation, duration and difficulties in the first four months postpartum. BMC. Pregnancy. Childbirth. 2016; 16:90.

12 Poston L et al. Preconceptional and maternal obesity: epidemiology and health consequences. Lancet Diabetes Endocrinol. 2016; 4(12):1025–1036.

13 Grajeda R, Pérez-Escamilla R. Stress during labor and delivery is associated with delayed onset of lactation among urban Guatemalan women. J Nutr. 2002 [cited 2019 Jan 18]; 132(10):3055–3060.

14 Brown A, Jordan S. Impact of birth complications on breastfeeding duration: an internet survey. Journal of Advanced Nursing. 2013; 69(4):828–839.

15 Thompson JF et al. Women's breastfeeding experiences following a significant primary postpartum haemorrhage: A multicentre cohort study. Int Breastfeed J. 2010; 5:5.

16 Dewey KG. Maternal and fetal stress are associated with impaired lactogenesis in humans. J Nutr. 2001; 131(11):3012S-3015S.

17 Lau C. Breastfeeding Challenges and the Preterm Mother-Infant Dyad: A Conceptual Model. Breastfeed Med. 2018; 13(1):8–17.

18 Billett HH. Clinical Methods: The History, Physical, and Laboratory Examinations: Hemoglobin and Hematocrit. 3rd. Boston; 1990.

19 Hurst N et al. Providing mother's own milk in the context of the NICU: a paradoxical experience. J Hum Lact. 2013; 29(3):366–373.

20 UNICEF, WHO. Protecting, promoting and supporting breastfeeding: The baby-friendly hospital initiative for small, sick and preterm newborns. Geneva, New York: WHO; UNICEF; 2020. 42 p.

21 Spatz DL et al. Pump early, pump often: A continuous quality improvement project. J Perinat Educ. 2015; 24(3):160–170.

22 Torowicz DL et al. Human milk and breastfeeding outcomes in infants with congenital heart disease. Breastfeed Med. 2015; 10(1):31–37.

23 Post EDM et al. Milk production after preterm, late preterm and term delivery; effects of different breast pump suction patterns. J Perinatol. 2016; 36(1):47–51.