Researchers in Norway have discovered that breast milk is not as important to the health of children and mothers as was previously thought. The study's results provide relief to mothers who do not breastfeed. The researchers from the Norwegian University of Science and Technology (NTNU) found that it is not the milk that makes breastfed babies slightly healthier than bottle-fed babies; rather a baby's health is determined before he or she makes their entrance into the world. The team, part of the Department of Cancer Research and Molecular Medicine at NTNU, says hormones play an important role in determining whether a mother will breastfeed or not. The researchers found a correlation between androgens - the hormones that control the development and maintenance of masculine characteristics - in pregnant women and how much the women breastfed after birth. 'Pregnant women who have higher levels of androgens breastfeed less,' explained Sven M. Carlsen, a professor for the Unit of Applied Clinical Research at NTNU. 'Probably, this is a direct effect of hormones that simply limit nursing ability, by reducing milk production in the breast.' Past studies found a connection between testosterone and breastfeeding ability. The androgen hormone testosterone was used in the past to stop production of milk when it was needed. 'This was one of the reasons that we wanted to investigate whether the effects attributed to mother's milk really should be attributed to hormonal factors in pregnant women,' Professor Carlsen said. The researchers also found that women who are overweight, who smoke or who suffer from the endocrine disorder polycystic ovary syndrome (PCOS) typically breastfeed less than their peers. The main link is that women in those categories have higher testosterone levels in their bodies when pregnant. 'It's thus not the woman's will to breastfeed,' Professor Carlsen points out. 'Women who had more testosterone in their bodies during pregnancy feel the effects of a hormone that limits breastfeeding. That is clearly why it is not as easy to breastfeed.' A crucial factor in determining a baby's health is the placenta, Professor Carlsen adds. 'What happens is that there are hormones that come from the foetus that are converted to testosterone and oestrogen in the placenta - if the process goes as it should,' he explains. 'This is an energy intensive process. If the placenta does not have enough energy, a portion of the testosterone that would have been converted to oestrogen is in fact not converted. Then what happens is that the testosterone goes to both the mother and child, and probably affects both of them.' The more testosterone a baby is exposed to as a foetus, the greater the chance it will suffer from obesity, PCOS (for girls) or type 2 diabetes. For the mother, her glandular tissue in the breasts will be less developed. The result is that she will not be able to provide enough milk, perhaps no milk at all, because the ability to produce milk will not develop in the best possible way. The research team underlines the importance of not blaming mothers who cannot breastfeed their babies. 'If you are pregnant, you should live as healthy a lifestyle as possible: quit smoking, cut back on your consumption of coffee and tea, and avoid alcohol,' Professor Carlsen says. 'And when you give birth, you will do the best that you can, if you want to breastfeed. Don't let overzealous health professionals give you a guilty conscience.' The only area the research found that breastfeeding is beneficial was in mental abilities. According to Professor Carlsen, 'it appears that children who are breastfed have a small IQ [intelligence quotient] advantage, but this needs to be confirmed in new, carefully planned and conducted studies'.