There is a growing trend in Israel and many other countries of tandem breastfeeding, in which a mother who breastfeeds two babies of different ages – a mother who breastfeeds a baby, becomes pregnant, continues to breastfeed, gives birth to a baby, and continues to breastfeed her two infants. Now, researchers at Tel Aviv Sourasky Medical Center have conducted the first study in the world on the effect of tandem breastfeeding on the composition of mother’s milk.
The study included 49 mothers, of whom 18 breastfed a tandem and another 31 who breastfed after the birth of one child. The composition of the macronutrients (proteins, carbohydrates, fats, and energy content that provide calories or energy and are required in large amounts to maintain body functions) in their milk was tested at three time points – in the last month of pregnancy (pregnancy milk), within 72 hours of birth (colostrum) and milk sample after two weeks of age (mature milk). The results were compared both within the group itself of tandem breastfeeding and to milk values taken from mothers who did not do tandem breastfeeding.
The study was published in the Journal of Human Lactation under the title “Tandem Breastfeeding and Human Milk Macronutrients: A Prospective Observational Study.” It was conducted in Sourasky’s breastfeeding research lab of preterm infants by Prof. Dror Mendel and Prof. Ronit Lubetzky and with the participation of Dr. Gilad Rosenberg (who conducted the study as part of his specialization in pediatrics), Dr. Laurence Mangel and Dr. Ronella Marom of Sourasky’s Dana-Duek Children’s Hospital.
They found that the composition of breast milk of a mother who performed tandem breastfeeding was different from the composition of breast milk in normal breastfeeding. Specifically, breast milk produced during pregnancy was found to have a higher protein content and a significantly lower carbohydrate content compared to colostrum and mature milk from the same mother. The fat and energy content of milk in pregnancy was not different from that in colostrum, but it was lower than that in mature milk.
The researchers concluded that the milk composition at the end of pregnancy is different from the postpartum milk composition. The milk produced during tandem breastfeeding has macronutrients suitable for newborns. The biological significance of this finding requires further research, they wrote, and should examine the content in breast milk of micronutrients such as vitamins, which are necessary for energy production, immune function and blood clotting and minerals for growth, bone health, fluid balance and several other processes.