Moms across the globe went into instant disarming mode when a video did the rounds in April showing a hunky father calming his newborn by using a simple “aa uu mmmm” chant.
Seen the one where a Cockatiel soothes a two-week baby to sleep with his birdsong? The baby is enraptured from the word go and soon settles down.
From the whoosh of a fan to the faint rumbling of a tumble dryer in the background, parents are always looking for fool-proof, yet unconventional, ways to get their fussy babies to sleep.
Experts call this background sound white noise and babies find it calming because it mimics the sound of the womb.
Paediatrician Dr Harvey Karp, author of The Happiest Baby, is the master of perfecting calming techniques. His theory on white noise is that parents should treat themselves as a “walking uterus” in the first three months after birth.
He has even gone as far as creating an audio disc with soothing white noise sleep sounds, which he claims flips the switch on baby's calming reflex and sets the mood for sleep.
What is white noise?
White noise is a combination of sounds on different frequencies. Examples of these background noises are a washing machine, vacuum cleaner or running water. Real white noise sounds similar to TV or radio static.
How it calms baby
Newborn babies can become stressed and overstimulated with unfamiliar sights and sounds, often leading to crying and colic.
“Babies are used to the loud whoosh of blood rushing through the placenta - and it's even noisier than a vacuum cleaner,” Dr Karp explained during an interview with the Huffington Post.
“This sound switches on the calming reflex and helps infants drift into slumber.”
Karp suggests this is why the calming “shhh” sound that parents make mimics the continual whooshing sound made by the blood flowing through arteries near the womb.
Smartphone apps have also become popular in recent years, as have infant sleep machines which are favoured by new moms with baby shower registries.
But does it work?
To some parents it may sound like new age mumbo jumbo, but a 1990 groundbreaking study, published in the Archives of Disease in Childhood, found conclusive evidence that white noise can be beneficial to infants. Out of a group of 40 newborns, about 80% were able to fall asleep after 5 minutes of being exposed to white noise.
But the technique does not come without its detractors.
A 2015 study conducted by The Hospital for Sick Children in Toronto found that some sleep machines produce sounds that could increase the risk of noise-induced hearing loss.
Dr Blake Papsin, paediatric otolaryngologist-in-chief at SickKids and one of the authors of the study, said that if 85 decibels is too loud for adults, then it's probably too loud for babies.
“Maybe if babies are comfortable falling asleep to a heartbeat, go to the crib and grab them, put them against your chest. Use the factory installed one,” Papsin said.
If anything, the study recommends that parents put the device as far as possible from the infant, never in or attached to the cot.
What the expert says
“Shushing is simply white noise that you make yourself. Playing white noise at a volume similar to the baby's cry will limit colic episodes”, states Megan Faure in her best-seller Baby Sense.
She recommends buying or making a recording of white noise “mixed” with a steady heartbeat.
“The first three months are a period of enormous transition and adjustment for you and your baby. By mimicking the womb world, you can calm your baby effectively. Swaddling, white noise, and carrying the baby are just three examples of strategies that imitate the womb world and calm babies in the fourth trimester.”