PHYSIOLOGY OF LACTATION

Abstract

29 May 2005 Dear Editor, I was interested in the report of deaths of two infants aged 6 weeks and five others mainly males near 6 weeks after birth all while at the breast. I would like to suggest a possible cause that does not seem to have been considered. The two died of asphyxia diagnosed as due to ‘oro nasal obstruction’. They were both ‘at risk’ babies with inexperienced mothers not concentrating on the baby's feeding in the critical 6 weeks period during which the baby learns to coordinate breathing with feeding and the mother's let down (draught) reflex stabilizes. Baby 1 was a male full-term, first-born baby delivered by Caesarean section for fetal distress showing some respiratory distress after delivery. The primiparous mother was absorbed in a film in a picture theatre when the baby became restless having started suckling stimulating the milk let down reflex. Mother assumed that restlessness was due to a bowel action and put him back on the breast after 15 min by which time it is not uncommon for a second let down to occur. This was followed by apnoea and post-mortem showed that the baby had died of asphyxia, which could have been from laryngeal obstruction. Baby 2 was a male born 2 weeks early with respiratory distress up to the 7th day and followed by readmission to hospital with jaundice. The mother was shopping with the baby in a sling and when he became restless having started breast-feeding in the sling, she continued upstairs shopping until she noticed that he had stopped breathing. Death and post-mortem 4 days later showed ‘diffuse alveolar damage’. My study of the let down (draught) reflex recorded by mothers and published 50 years ago in The Archives of Disease in Childhood, Vol. 29, No. 143, 1954, showed the developing pattern of the let down reflex. In the first weeks of lactation, milk is usually already down when the baby is put to the breast, but the reflex takes a few seconds for let down by 6 weeks often with considerable force of milk ejection that can confuse the baby's feeding and breathing control. This was when these babies suffocated. Ultrasound studies in University of Western Australia by Donna Ramsay et al. are confirming multiple let downs, but there have not been reliable studies yet of the force and variability in this highly emotional few weeks. This is often not recognized by primiparae who do not experience the let down sensation that often only becomes felt in the 3rd to 6th week. A forceful gush of milk could have been very dangerous for these babies recovering from early respiratory distress with impaired respiratory reflex response, being nursed in difficult even horizontal positions with mother's attention distracted. I now have a number of breast-fed great grand children with many books on rearing babies, attending groups and advised by lactation experts, but they do not seem to get taught the basic physiology of lactation and methods of helping the baby to adjust to the reflex in the first important 6 weeks. I do not wish to suggest that a neonatal paediatric great grandmother should be interfering and scaring mothers, but it would help to give them some gentle education in lactation physiology.