Energy required during pregnancy is surprisingly higher than the previous estimates

Babies bring immense joy to parents, especially to the birthing parent, as growing a new human is no easy feat. Many who have experienced pregnancy agree it takes a toll on the body. A recent study quantifies the energy required to grow a baby, revealing it to be much higher than previously thought, as reported by The New York Times.

It takes about 50,000 calories to grow a baby in nine months, per the study conducted by Australian researchers, published in Science Journal. The amount of calories is equivalent to 50 pints of Ben and Jerry's Cherry Garcia ice cream, per the researchers. The previous estimates were much lower as scientists believed that most of the energy required for reproduction was stored in a fetus. 

However, Dustin Marshall and his students at Monash University, Australia, discovered that the energy stored by a fetus only accounts for 4 percent of the total energy required by the baby as per the outlet. The remaining 96 percent has to be provided by the woman's body in the form of energy. The discovery made by Marshall and his students came out of his study of metabolism. He found out that different species have different energy requirements. 

For instance, warm-blooded animals can maintain steady temperature levels and energy even when the temperature drops. But there is a downside to being warm-blooded as well. Cold-blooded animals can go on for weeks without a meal. The same is not true for mammals who need to "feed the furnace." Also, it leads to mammals having a higher indirect cost of pregnancy than cold-blooded animals, per Think Tank. 

Marshall and his team accounted for the pregnancy costs for 81 species, as per Motherly. According to the research, the pregnancy cost is usually proportional to an animal's size. A microscopic organism might need a millionth of a calorie, but an animal like a white-tailed deer doe might need 112,000 calories to produce offspring. Humans might also end up giving a higher pregnancy cost because women are pregnant for a longer time than most mammals.

The most surprising outcome of the research was that indirect costs of pregnancy can be much higher than direct costs. The researchers found out that only 10 percent of the energy used by females went into their offspring on a daily basis. "It shocked me. We went back to the sources many times because it seemed astonishingly high based on the expectation from theory," Dr. Marshall shared. 

Another reason behind such a high pregnancy cost could be that mammals have to build a placenta to fulfill the nutritional requirement of a baby, which takes a lot more energy than a female that lays eggs. He also added that this phenomenon of such a high pregnancy cost also explained the reason why mothers are so invested in the well-being of their children because they have already paid a high cost to grow them inside their bodies.

The researcher was also quite surprised to be the first person to put together these numbers. "It is disarming. You think someone has done this before," he remarked. The previous estimate of the energy used by women to fuel their bodies was thought to be 20 percent of the energy in the baby's tissues, which is much lower than what the team found. The team didn't accept speculations and set out to make their own findings. "Folks were just poodling along, collecting their data on their species, but no one was putting it together," the professor explained.