6 remarkable facts about the science of motherhood

 

Mother's Day is approaching.

Yeah, the holiday has developed from an idealized celebration of the mother-child relationship to a corporate-driven occasion for mass consumption, but that shouldn't diminish the essential value of mothers.

On a biological level, science has revealed a plethora of interesting facts about the biologically unique bond between mother and infant.

1) In the womb, babies begin to listen to their mothers' voice.

In 2013, researchers in Tacoma, Washington, and Stockholm, Sweden, conducted a fascinating study with 80 newborns in which they played sounds in English, Swedish, and other languages.

Since it's well known that babies enjoy new interactions, the researchers decided to see if the babies were more interested in noises made in languages other than their mothers'. They did, it turns out: by sucking on a pacifier, the newborns could monitor how long the sounds played, and they consistently sucked more for sounds in languages other than their own.

The researchers conclude that the newborns registered and habituated to their own mothers' speech while still in the womb, which is a rational assumption considering that the neurological processes necessary for hearing development begin about 30 weeks after conception.

2) Saliva from a mother can be beneficial to a baby's health.

For years, some mothers who had dropped their babies' pacifiers on the ground would pick it up, suck it clean, and replace it in the baby's mouth. This was strongly discouraged by experts (including the New York City Department of Health).

However, Swedish researchers discovered something surprising about this apparently disgusting habit this year: parents who do it have children with slightly lower rates of allergies, eczema, asthma, and other auto-immune diseases.

This is just a link, not a cause, but it fits with the hygiene theory, which claims that recent rises in many auto-immune diseases are due to an over-sanitized childhood climate that prevents a child's immune system from learning to distinguish between minor and major threats. Sharing spit may be one way to get these important microbes into a baby's system. 

3) Breast milk has a variety of immune-boosting properties and can also protect against HIV.

Breast milk is well known for offering a range of nutritional benefits that formula cannot equal. One of these is the immune system support it provides: breastfed babies are more resistant to infections of the respiratory system and digestive tract during early childhood due to antibodies transmitted by a mother's milk.

Breast milk, however, has recently been discovered to protect against a very different form of infection: HIV.

Just about 10 to 20% of infants breastfed by HIV-positive mothers contract the virus globally, according to new findings. Tenascin-C is a protein found in all breast milk that binds to the virus and prevents it from destroying human cells.

It does not prevent HIV transmission in all cases, but it does in the vast majority of them. This, along with the many health benefits of breast milk, is why the UN recently recommended that HIV-positive mothers breastfeed as long as they are taking antiretroviral medications.

4) Skin-to-skin contact with a mother improves the health of premature babies.

Kangaroo care, which involves a mother holding a premature baby against her chest for at least a few hours per day, is becoming more common in hospital neonatal care units, thanks to studies showing that it has a variety of health benefits for newborns.

Studies have shown that regular kangaroo care can help premature babies gain weight faster, be more resistant to infections and hypothermia, and feel less discomfort during unpleasant procedures like heel lancing, as compared to holding them in incubators.

The truly fascinating aspect is that scientists are still baffled as to how kangaroo treatment delivers these benefits. It seems to operate only when the baby is naked (or in a diaper) and is kept against the mother's (or father's) bare skin. Skin-to-skin contact can induce the release of the hormone oxytocin in both the baby and the mother in a specific way, but scientists aren't sure.

5) It's possible that a mother's brain contains cells from her children.

The placenta binds the mother and the fetus during pregnancy, allowing nutrients to flow from the mother to the fetus and waste to flow in the opposite direction. The organ is made up of cells from each of them, and the cells will migrate through it, eventually ending up in the other's body and multiplying for years.

As a result, an estimated 50% of mothers bear their children's cells inside them, most usually in the skin and organs such as the lungs, liver, and kidneys. It is also possible for a mother's cells to end up in her fetus, but this is less common.

Scientists have recently discovered that a child's cells can travel all the way to a mother's brain in many cases. Their findings also indicate that women with more of these cells have a lower risk of Alzheimer's disease, for unknown reasons.

6) The phrase "mother" is believed to have arisen at the end of the Ice Age.

This isn't necessarily genetics, but it's a fascinating piece of science about motherhood all the same.

Linguists recently looked at cognates shared by a number of language groups, including Uralic (which includes Finnish and Hungarian), Dravidian (which includes South Indian languages), and Inuit-Yupik (which includes Arctic languages).

They discovered that there are at least 23 "ultraconserved words" that are shared across all of these languages since they haven't changed much since around 15,000 years ago by mapping the words' relationships and using what we already know about the rates at which languages mutate over time. In other words, humans used to use these words in a similar way to how we do now, back when ice still covered much of Europe and North America and woolly mammoths roamed the World.

Fire, worm, old, spit, and, of course, mother are among them.

The fact that our forefathers used the term "mother" so long ago does not come as a surprise. However, its presence on a list of seemingly insignificant physical artifacts is intriguing — and suggests just how important mothers are to the human experience as a whole.

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