Associated Press
Consultant physician Matthias Knuepfer and nurse My take care of Germany's heaviest newborn until now at the neonatal intensive care ward of the University Hospital in Leipzig, Germany, Monday, July 29, 2013. Girl Jasleen was born four days ago weighing an extraordinary 6,110 grams (13.47 pounds) and measuring 57.5 cm (22.5 inches) in length. The mother only arrived at the hospital on the day of the birth and suffers from an undiscovered gestational diabetes.
In some ways very large babies look more mature because of their size. But in terms of their lungs, they may be immature. —Dr. Hyagriv Simhan

Although many people love chubby newborn babies, the rise in "supersized" babies has doctors concerned.

Recently, babies born weighing more than 13 pounds at birth have made headlines. Earlier this month, a British mom in Spain gave birth to a 13-pound, 11-ounce daughter. Baby Maria Lorena is the new record-holder for heaviest baby born naturally in Spain. In July, a baby girl was born in Germany and weighed 13 pounds, 4 ounces, a new record in Germany. In February, a British woman gave birth naturally to a 15-pound 7-ounce son named George, making him the second heaviest baby in U.K. history to be born naturally.

Although heavy babies may run in some families, Harvard researchers at Children’s Hospital Boston found excess maternal weight gain is a strong predictor of high birth weight. The study was published in the British medical journal The Lancet.

The rising rates of obesity and higher rates of gestational diabetes that come with delay in childbearing are causing newborns to be heavier. Children who are born heavier have an increased risk of health issues, including a risk of obesity later in life.

"Since high birth weight, in turn, increases risk for obesity and diseases such as cancer and asthma later in life, these findings have important implications to general public health,” co-author David Ludwig, a Harvard Medical School associate professor of pediatrics and director of the Optimal Weight for Life (OWL) program at Children’s Hospital Boston, told the Harvard Gazette. "It’s appropriate for a baby to be born with some fat, but a baby born too fat indicates that the fetus developed in an abnormal environment during the most critical nine months of life."

Babies weighing more than 4,000 grams or 8 pounds, 13 ounces are considered oversized. According to another report in the medical journal The Lancet, there’s been a 15 percent to 25 percent increase in babies born oversized in the past two or three decades in developed countries.

The study found that nearly 15 percent of babies born in Algeria, where maternal obesity is almost 30 percent, were oversized. Nearly 7 percent of babies born in China are considered oversized due to rising obesity rates among the Chinese.

Although oversized babies are becoming a trend around the world, doctors have been addressing the issue in the United States for years. The efforts have led to the average weight of full-term newborns (not born in multiples) to drop to around 7 pounds.

Caesarian sections for single babies in the United States have increased nearly 20 percent from 1996 to 2009, but the percent has remained around 32 percent since 2009.

Oversized babies can pose a risk for both mother and child during birth, NBC reported. The paper went on to say the the most common risk is shoulder dystocia, where oversized babies have their shoulders grow to be larger than their head, which can cause the child to become stuck during delivery.

Overweight mothers are also at an increased risk to develop diabetes during pregnancy, NBC reported, and high blood sugar can cause the fetus to be born with low blood sugar, which can delay growth in the fetus.

"In some ways very large babies look more mature because of their size," Dr. Hyagriv Simhan, chief of maternal fetal medicine and vice chairman for obstetrics at McGee Women’s Hospital at the University of Pittsburgh Medical Center, told NBC News. "But in terms of their lungs, they may be immature."

Pregnant patients who are obese are encouraged by doctors to gain very little weight during pregnancy. There currently are clinical trials researching the impact of a drug that could help keep blood sugar low in pregnant women who are obese.

The heaviest baby born naturally according to "Guinness Book of World Records" was 23 pounds 12 ounces. Born to Canadian Anna Bates who was 7 foot 5.5 inches, the baby boy was 30 inches long and was born in Seville, Ohio, on Jan. 19, 1879. The baby died 11 hours after birth. The heaviest baby to survive after childbirth weighed 22 pounds 8 ounces. Carmelina Fedele gave birth to the boy at Aversa, Italy, in September 1955.

Editor's Note: The original version of this story posted on Aug. 19, 2013, failed to properly attribute all source materials, which violates our editorial policies. The story was revised on Oct. 10, 2013, to link to original source material.

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