The incredible fetal heart rate

Every expectant mother I’ve ever known has remarked on the incredible speed of their baby’s heartbeat in utero. They say it sounds unbelievably fast, almost as though it is going to just beat right out of their tiny chests. I’ve heard many worry their baby’s heart would never slow to the normal rate, only to be stunned when the baby is born to listen to her/his heart gradually slow and even out. It was my grandmother, however, who really got me thinking about the changes a baby’s heart goes through after birth.

My cousin was drawing close to her pregnancy due date, and we were at a family gathering discussing her plans for the birth. She was going back and forth about whether she wanted the newborn to go to the nursery after the birth so she could get some rest. My usually silent grandmother suddenly piped up, saying, “You better not let them take the baby to the nursery or his heart won’t beat properly.” When we asked her what she meant, she explained that a baby’s heart can’t learn to beat correctly if her/his mother doesn’t hold him after he/she is born. Being close to her teaches his/her heart the right rhythm and helps her/him breathe in the correct pattern. I had never heard this, and it really made me wonder how much of her homespun wisdom was actually true.

Do mothers really “teach” their babies’ hearts to beat?

Extensive research has been done into the regulatory and sensory development of children from birth. Though there have been many techniques utilized, one of the consistent findings is that children with consistent contact, particularly skin-to-skin contact, with their mothers after birth tend to have more regular, well-controlled heart rates and breathing patterns. This is true even of babies and young children who have shown signs of regulatory or sensory issues experiencing a leveling and stabilization of their vital signs when held close to their mothers. Another intriguing study has demonstrated babies’ heart rhythms change in response to sucking. Using a variety of fluids, research gauged the response of infants to sucking. The newborns consistently sucked more slowly when a sweet fluid was introduced. Their heart rate simultaneously increased. Due to the sweetness of breast milk, it can be theorized that nursing provides pleasure beyond just the actual satiation. A benefit of this activity may be a stronger, more even heart rhythm.

Source: Charles K. Crook and Lewis P. Lipsitt.Child Development. Vol. 47, No. 2 (Jun, 1976), pp. 518-522