Breast Volume and Milk Production During Extended Lactation in Women

Abstract

SUMMARY Quantitative measurements were made of relative breast volume and milk production from 1 month of lactation until 3 months after weaning, and the storage capacity of the breasts was calculated. The increase in breast tissue volume from before conception until 1 month of lactation was maintained for the first 6 months of lactation (means ±s.e.m.) (190·3 ± 13·1 ml, number of breasts, nb= 46). During this period of exclusive breast‐feeding, 24 h milk production from each breast remained relatively constant (453·6 ± 20·1 g, nb= 48), and storage capacity was 209·9 ± 11·0 ml (nb= 46). After 6 months, breast volume, milk production and storage capacity all decreased. There was a relationship between 24 h milk production and the storage capacity of the breasts, and these both appeared to be responding to infant demand for milk. At 15 months of lactation, the 24 h milk production of each breast was substantial (208·0 ± 56·7 g, nb= 6), even though the breasts had returned to preconception size. This was associated with an apparent increased efficiency of the breast (milk production per unit breast tissue) after 6 months, which may have been due to redistribution of tissues within the breast. The possible causes of the decrease in breast volume are discussed.

Report of a Staff Program to Promote and Support Breastfeeding in the Care of Vulnerable Infants at a Children's Hospital

“…Initially, vulnerable infants do not require large volumes of breast milk, but the establishment of the supply is crucial during the first 1 to 2 weeks following birth. Our institutional policy recommends mothers work to establish and maintain a 24-hour milk production between 500 and 1,000 cc's, which is consistent with the normal range of milk production at Stage 2 lactogenesis, as reported in the literature (440 to 1,220 cc's per 24 hours) (Kent, Mitoulas, Cox, Owens, & Hartmann, 1999).…”

Physiology of milk secretion

“…When lactation is extended beyond 6 months, a significant decrease of the mammary tissue occurs gradually accompanied with a slight decline of the volume of milk produced and changes of its composition [93]. Breast returns to its preconception size after~15 months of lactation.…”

Scientific Opinion on Mineral Oil Hydrocarbons in Food

“…According to the German DONALD study, the mean consumption of infant formula for a three months old child weighing on average 6.1 kg was 780 mL per day with a 95 th percentile consumption of 1 060 mL per day (Kersting et al, 1998). A rounded mean consumption value of 800 g per day, with a high of 1 200 g per day for breast milk and infant formula (Kent et al, 1999) for a 3 month old child will be used here as in other recent EFSA opinions on contaminants to calculate exposure in breast-fed infants. In line with the Guidance on selected default values to be used by the EFSA Scientific Committee, Scientific Panels and Units in the absence of actual measured data (EFSA, 2012), a body weight of 5 kg will be assumed for breast-fed infants.…”

“…As occurrence values, the mean levels detected in breast milk from Table 2 have been used: LB = 1.8 mg/kg, UB = 2 mg/kg. As consumption, a mean value of 800 g milk per day, with a high of 1 200 g per day have been chosen (Kent et al, 1999). Taking into account that the MOSH content of milk is expected to decrease during lactation (Concin et al, 2008) and -on the other hand -that it is often recommended to continue breast feeding until at least 6 months, it was decided to refer the calculation to a 3 month old child weighing 5 kg (EFSA, 2012).…”