It’s not often that you come across someone who absolutely loves your body odour, and if you do, you’re likely to be a little sceptical. So most of us self-consciously slather ourselves with deodorant every day, lest someone be offended by a whiff of our ‘organic cologne’.
But a month or so after giving birth to my first child, I found that, magically, deodorant no longer had any effect. I applied more every morning, washed my clothes more frequently, and tried different deodorant brands, convinced that the big cosmetics companies were changing their formulas. Alas, I still smelled like a zoo animal.
This wasn’t bothersome to me personally, as I’m not particularly offended by my own odours, nor did it seem to bother my newborn (I didn’t ask my partner, but he didn’t complain!). However, I was worried about my funk invading other people’s nostrils. It was such an unprecedented bodily change that had occurred so soon after giving birth that there just had to be something interesting going on – something more than just coincidence.
Ever-fascinated by biological mysteries, I did my research. A large number of forums revealed that women all over the world were experiencing the same issue, and of course, having a newborn and extra body odour was no coincidence at all. It turns out that lactation increases the ratio of testosterone to oestrogen and progesterone in the body, testosterone being the hormone that makes for smelly armpits (think teenage boys).
Well, mystery solved. But I was a little disappointed by this simple, medical answer; I wanted to know exactly how this hormonal change and its accompanying odour boost related to new motherhood.
I knew that for a newborn baby, the scent of its mother is the single most appealing odour in the universe (how’s that for an ego boost, ladies?). But apparently, an infant can also recognise the scent of its own amniotic fluid as early as the last trimester of pregnancy. That’s right: babies can smell in utero!
During the first few days of life, a baby’s smell preference shifts from amniotic fluid to the smell of its mother. Skin-to-skin contact, particularly while breastfeeding, helps the baby to learn the unique scent of its mother and associate this smell with feelings of comfort and protection. By two weeks of age, a baby can tell the difference between the smell of its mother’s breast milk and that of another woman.
Scientists think this might help explain why a newborn crying in the arms of a relative is often quickly pacified when handed back to its mother. (And here I was thinking I had the special touch, when really, I just had the special smell!)
Clearly, sense of smell is an extremely important part of mother-infant bonding. After all, in evolutionary terms, a newborn needs to learn quickly who to turn to for food and protection, and its other four senses aren’t really up to the task immediately after birth.
It turns out that this smell bond goes both ways. Ever wondered why your baby smells so good? While nobody really knows what that smell is exactly, scientists have recently learnt that in new mothers, the body odour of newborns activates the part of the brain that perceives reward and pleasure – and makes the women crave more. The result? A strong and interdependent bond between mother and infant.
Reading all this about smells, I suddenly remembered the pet mice I had as a child. One morning, I had uncovered several tiny, hairless baby mice (can you imagine my delight?!). ‘Don’t touch them,’ my dad had said, ‘the mother mouse might reject her babies if they smell like humans’ (oh, the temptation for an animal-loving three-year-old!).
But he was right, just as in humans, studies in animals have shown that all mammals, from mice to primates, use their senses of smell to establish and develop a mother-infant bond.
So, if the first few weeks of my baby’s life were all about bonding, and smell is one of the most important elements in the bonding process, and we’re both just loving the smell of one another, surely my extra smelly armpits were also playing a role?
Or was I just finding an excuse to stop persevering with the ineffectual deodorant? Perhaps not: researchers in the psychology unit at the University of California were there to back me up, revealing that overzealous application of perfume during the first few days after birth can obscure the mother’s scent and block mother-baby bonding.
By no means am I a scientist, nor am I in possession of a particularly logical mind, but it makes sense to me that if my body is creating a little extra smell – an added spritz of ‘Me Cologne’ – then it’s surely helping my little daughter to know just which human is her mother: yep, the stinkiest one in the room!
‘Weird post-partum symptoms’, by Dr. Shelley Binkley, M.D., HEALTHe Woman, accessed on 9 February 2014
‘Wired for fast-track learning? The newborn senses of taste and smell’, by Gwen Dewar, Ph.D., Parenting Science, 2009, Content last modified May 2011, accessed on 9 February 2014
‘SCIENCE WATCH: The Key Role of Smell In an Infant’s Bonding’, The New York Times, 30 April 1991, accessed on 9 February 2014