Consider this – you’ve just put your little one to bed after an exhausting breastfeeding session. Just when you thought that you’re in a deep sleep, you promptly wake up to your baby’s cries. Or, you are in your last trimester and relaxing all by yourself. Just then you hear a baby’s cry in the neighborhood and you realize you are having a milk letdown. Sounds familiar? All these experiences are absolutely normal for any new or soon-to-be mother. And, there is a reason behind it.
Babies, especially newborns, use crying as a way to communicate their needs and feelings to their mother. Be it pain, hunger, discomfort, or simply the need for some cuddling from their mommies, babies cry to catch their mum’s attention. Most mothers feel concerned whether they’ll be able to respond to their babies on time. Or, for that matter, will they be able to respond at all? Worry not. Now you can set aside all your doubts. Because, here comes science to your rescue!
It is common knowledge that a pregnant woman or a new mother has high levels of oxytocin, the hormone responsible for maternal behavior. But little was known earlier about how oxytocin exactly worked. A research was conducted recently on female mice by accelerating their left auditory cortex with oxytocin and then studying their pup-retrieval behavior. The researchers noticed that those female mice who were injected with oxytocin responded quickly to the cries of their little pups. No sooner did they hear the cry that they would run in their direction, pick the lost pup, and return to the nest. Sometimes, the female mice responded to pups which were not even their own. Not only that, a similar reaction was found even in virgin mice who were injected with oxytocin (1).
In a separate new study, it was found that mothers across the world showed a universal response to their babies’ cries, both in their brains as well as their behaviors. According to this study, which was conducted on mothers from 11 countries, all mothers showed a consistency in picking up, holding, or talking to their babies when they heard them cry. The researchers studied and recorded almost an hour of interaction between each of the mothers and their babies involved in the study. Then, through the help of MRI technology, they scanned the mothers’ brains every time they heard their own infant’s cry. These MRI scans found that hearing the infant’s cries generally activated those regions in the mother’s brain that are associated with the intention to grasp, speak, or move (2). All of this as a part of the care-giving response.
Based on this observation, the researchers found that the mothers took a rather short time to respond to their babies’ cries. They calculated that a mother, on an average, took only 5 seconds to respond to her crying baby (3)! It is this very response-to-stimuli formula that wakes up a mother even from her deep sleep every time her baby cries.
Another reaction that a baby’s cry trigger in a mother is a breast milk letdown. Here too its the same old oxytocin at play again. This hormone contracts the myoepithelial cells around the alveoli of the breast, causing the milk to eject. This is also known as the ‘Milk Ejection Reflex’. This reflex eventually becomes completely conditioned to the mother’s feelings. So much so that it starts ejecting milk whenever a mother smells or touches her baby, thinks about her baby, or hears him/her cry. Sometimes it causes a milk letdown even on hearing a baby’s cry which does not belong to the mother (4). Much like the mother mice who’d go looking for a pup which was not their own, in the research mentioned above. Such an experience is something that most new mothers would vouch for!
Now you know what happens to a mother’s brain whenever she hears her baby cry. It is the oxytocin that is the culprit (in a good-natured way!). But wait a minute! This new knowledge also means something. The next time someone mentions ‘maternal instincts’, you know where it’s coming from!