Coming to volume – Effective initiation results

Coming to volume is an indicator of the efficacy for the interventions to support effective initiation. Coming to volume, defined as achieving ≥500 ml per day, within 14 days of birth is the strongest predictor of own mother’s milk (OMM) feeding at NICU discharge home. When NICU mothers are supported to initiate lactation effectively, they can achieve their breastfeeding goals.

Graph showing critical window to build milk supply

What is coming to volume?

Coming to volume (CTV) refers to the lactation stage between secretory activation (milk ’coming in‘) and the establishment of a minimum daily milk volume of around 500 ml that typically occurs between 4-7 days postpartum in healthy breastfeeding mothers and infants.1 

Coming to volume is defined as achieving a threshold of  ≥500 ml total daily milk volume by postpartum day 14.2-4

Why is coming to volume important?

Achievement of CTV within 14 days postpartum has been shown to be the strongest predictor of the infant receiving own mother’s milk (OMM) feedings at NICU discharge.2 Mothers who produce less than 500 ml/day by day 14 are likely to have less than adequate milk production long-term.2

When supported with evidence-based best practices, such as early and frequent expression5, CTV can serve as a quality indicator for improving OMM feedings in the NICU.2

Evidence-based practices to track CTV enable NICU mothers (who are pump-dependent) to achieve milk volumes similar to those of exclusively breastfeeding mums.3,5,6

CTV is the stage associated with the greatest risk of suboptimal breastfeeding and early, unplanned weaning in otherwise healthy populations. Mothers who are partially or exclusively pump-dependent are at a significant risk during this critical window.3,7

Once mums have come to volume there is a switch from endocrine to autocrine (or local) control of lactation. Milk synthesis will be controlled at the breast and milk removal is the primary control mechanism for supply.6,8

CTV is a one-time event in the mother’s lactation journey.3,9 As time passes, it becomes more difficult to significantly increase milk supply when sub-optimum interventions indicate a delay in secretory activation and milk volumes <500 ml during this critical 14-day period.4

How to optimise coming to volume

  • Inform and instruct mothers to initiate pumping early, express frequently, double pump and use correctly fitted breast shields5,9-12
  • Provide mothers breast pumps with the INITIATE program until secretory activation is attained. After this, switch to the MAINTAIN program to drain the breasts effectively and support building milk volume.4,6

  • Instruct mothers to track pumping frequency and volume during the critical 14-day period by completing pumping logs.5

  • Inform mothers about the minimum CTV targets to empower them to seek early support.4

  • Provide regular staff education around lactation best practices to support CTV.

  • Educate staff and inform mothers that CTV and building a milk supply may mean greater milk volumes than the infant’s current requirements.13

  • Ensure that pumping logs are reviewed daily.5,10,13

Integrate specialist lactation support for when mothers are not achieving ≥500 ml within 14 days of birth

How to monitor coming to volume

  • 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’

  • Collect data on frequent expression with a data collection tool

  • Review pumping logs and collect daily milk volumes (ml/day)

  • Carry out monthly audits of the data to measure the average daily milk volume during the first 14 days postpartum

  • Identify hospital practices where mothers may not achieve early and frequent expression

  • Identify contributing factors such as availability of double pumping, correctly sized breast shields, home-use pumps, time that reduce pumping frequency and efficiency

  • Communicate findings and recommendations regularly to all departments to improve and sustain best practice


1 Chen DC et al. Stress during labor and delivery and early lactation performance. Am J Clin Nutr. 1998; 68(2):335–344.

2 Hoban R et al. Milk volume at 2 weeks predicts mother's own milk feeding at Neonatal Intensive Care Unit discharge for Very Low Birthweight infants. Breastfeed Med. 2018; 13(2):135–141.

3 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.

4 Meier PP et al. Evidence-based methods that promote human milk feeding of preterm infants: An expert review. Clin Perinatol. 2017; 44(1):1–22.

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

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 Spatz DL. Getting it right – the critical window to effectively establish lactation. Infant. 2020; 16(2):58–60.

8 Daly SE et al. Frequency and degree of milk removal and the short-term control of human milk synthesis. Exp. Physiol. 1996; 81(5):861–875.

9 Meier PP et al. Human milk in the neonatal intensive care unit. In: Family Larsson-Rosenquist Foundation, editor. Breastfeeding and breast milk - From biochemistry to impact: A multidisciplinary introduction. 1st ed. Stuttgart: Thieme; 2018.

10 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.

11 Prime DK et al. Simultaneous breast expression in breastfeeding women is more efficacious than sequential breast expression. Breastfeed Med. 2012; 7(6):442–447.

12 Sakalidis VS et al. Breast shield design impacts milk removal dynamics during pumping: A randomised controlled non-inferiority trial. Acta Obstet Gynecol Scand. 2020; 99(11):1561-1567.

13 Spatz DL. Innovations in the provision of human milk and breastfeeding for infants requiring intensive care. J Obstet Gynecol Neonatal Nurs. 2012; 41(1):138–143.