A newborn in Iowa made headlines Monday because—at  13 pounds, 13 ounces—Asher Stewardson is an exceptionally large baby boy.  His mother Kendall gave birth to him naturally, meaning no surgery and no epidural.  

I want to stress that these size babies are not the norm.  National health statistics indicate that only one in every 1,000 babies is born weighing more than 11 pounds.

While big babies can run in families, as what appears to be the case here, most large gestational infants are a product of gestational diabetes.  Gestational diabetes is a common condition in pregnancy that occurs when women have difficulty metabolizing sugars. The sugar, or glucose, is then freely transported to the newborn in utero, and this is what causes excessive weight gain.

When you look at these babies with a sonogram, typical characteristics include overall high fetal weight and increased abdominal girth as they develop.

That is why glucose testing of the mother is imperative, as well as serial ultrasounds to monitor fetal weight gain. Babies that are excessively overweight are at risk for many complications, including birth trauma and electrolyte abnormalities.

One major potential problem that can arise during natural births of large infants is shoulder dystocia.  This is when the infant’s head is delivered, but the shoulder is trapped underneath the pelvic bone.

Injuries resulting from shoulder dystocia can be quite severe – ranging from cerebral palsy to dysfunction of the nerve.  Even though this particular delivery was successful, I would caution women to pay attention to recommendation of their OB-GYN in regards to a vaginal delivery of a very large infant.

So, while  I’m happy for the Stewardson family for delivering what by all accounts appears to be a healthy baby boy, I do hope this story serves as a reminder of how important it is for mothers-to-be to follow a healthy diet during pregnancy and heed the advice of their OB-GYN.  

Dr. Manny Alvarez serves as Fox News Channel's senior managing health editor. He also serves as chairman of the department of obstetrics/gynecology and reproductive science at Hackensack University Medical Center in New Jersey. Click here for more information on Dr. Manny's work with Hackensack University Medical Center. Visit AskDrManny.com for more.