A woman in New York was left stunned after delivering a baby boy weighing 5.9 kilograms (nearly 13 pounds), making him one of the heaviest newborns reported in recent years.

Terrica, a mother of four, said she expected her baby to be “a little big” but did not anticipate such a weight. The newborn is already wearing clothes and nappies meant for three- to six-month-old babies. Hospital staff even shared a photo comparing the baby’s size to another infant born the same day.

Doctors say such cases are usually linked to a condition called Fetal macrosomia, where a baby weighs more than 4 kg at birth, regardless of gestational age. In more severe cases, the weight can exceed 4.5 kg, significantly increasing delivery risks.

What causes macrosomia?

Several factors can contribute to fetal macrosomia, including:

  • Gestational or pre-existing diabetes
  • Maternal obesity
  • Excessive weight gain during pregnancy
  • Previous history of large babies
  • Post-term pregnancy
  • Male fetus (boys typically weigh slightly more at birth)

Among these, gestational diabetes is one of the most common causes. Elevated blood sugar levels during pregnancy can lead to increased insulin production in the fetus, resulting in excessive growth.

Is it dangerous?

While many large babies are born healthy, macrosomia can increase the risk of complications.

For mothers, risks include prolonged labour, perineal tears, postpartum haemorrhage, and a higher likelihood of Caesarean delivery. For babies, complications may include shoulder dystocia (where the shoulder gets stuck during delivery), birth injuries, and low blood sugar levels after birth.

Long term, some studies suggest a higher risk of childhood obesity and type 2 diabetes.

Can it be prevented?

Although genetics play a role, doctors recommend maintaining healthy weight gain during pregnancy, regular prenatal check-ups, and strict blood sugar control where required.

In this case, the baby is reportedly healthy and under monitoring, highlighting that while macrosomia carries risks, many outcomes remain positive with proper medical care.