Why Newborn Babies are Bigger Than They Used to Be

Most of the time, it's hard for anyone who works outside the field of medicine to notice patterns and changes in healthcare. But one factor that almost any layperson can observe is the ever-increasing size of newborn babies. While there are exceptions (as always), the newborn babies of your family probably weighed a little less than seven pounds 30 years ago, while today's newborns weigh in at an impressive seven and a half pounds on average. When you consider that we're working with pretty small numbers, that's a huge difference. But why is it happening?

According to the Journal of Pediatrics, there are several reasons that today's babies are a lot heftier than they were a few decades ago. One is, thankfully, that fewer moms are smoking. Smoking during pregnancy causes preterm labor, and even when it doesn't, it causes babies to be born smaller than they would normally be. Many of us born in the 1970s or 1980s, when smoking in pregnancy wasn't nearly as taboo, turned out to be on the small side because of this. Now, far fewer moms smoke, so the birth weight is going up.

That's the good news about why babies are chubbier today, but there's also bad news behind our increasingly fluffy munchkins. Obesity rates have continued to climb for the last several generations, and today's mamas are bigger than ever. If you're obese when you become pregnant, you're much more likely to have a chubby newborn. Higher obesity rates also mean that more moms are getting gestational diabetes, which, because of the way it affects the baby's insulin levels, causes babies to be much bigger.

Changing trends in healthcare are also a big factor. Moms today are just a little bit taller than moms of the past, thanks to better childhood nutrition. Mom's height is one of the factors that can determine how big a baby ends up being, since nature tries not to give big babies to moms who are too small to give birth to them. Also, today's mamas are advised to gain between 20 and 35 pounds during pregnancy if they start out at a healthy weight, compared to the 15-20 pounds that were recommended 40 years ago. That adds up to create a much bigger baby.

There are both positive and negative sides to the chubbier newborns of today. Babies who are very small at birth do tend to be sicker and more fragile, so doctors usually want to see babies weighing at least six and a half pounds. But when babies are too big -- nine pounds or more -- they're more prone to obesity and related problems, like heart disease and diabetes, later in life. That's why it's important to make healthy decisions, like eating right and not smoking, during pregnancy, and to shy away from decisions that could adversely affect your baby's health in one way or another. If you play your cards right, the odds are good that your baby will be born a healthy weight, whether that's a little bigger or a little smaller than today's average