What Are the Dangers of Low Weight in Babies?

How much your newborn weighs is one of the first questions your family and friends ask after your delivery 1. A normal birth weight falls between 5 pounds, 8 ounces and 8 pounds, 13 ounces, according to KidsHealth. If your baby weighs less, he has a low birth weight. While being born tiny doesn't necessarily mean your baby will have health problems, many babies with a low birth weight are at a higher risk for certain medical conditions.

Definition and Causes

A baby that weighs less than 5 pounds, 8 ounces at birth has a low birth weight, and about one in 12 babies falls into that category, according to the March of Dimes 2. About two-thirds of all babies born with a low birth weight are premature, but additional causes can lead to the condition. Problems with the uterus growing normally can restrict growth. A mother's health can also affect growth in the womb. High blood pressure, diabetes, heart problems and lung conditions can restrict growth. If a mother smokes, drinks or uses illicit drugs, it can also lead to low birth weight. Certain infections or being pregnant with twins, triplets or multiples can also lead to low birth weight, too.

Immediate Dangers

A baby born with low birth weight can experience symptoms immediately after delivery. Low birth-weight babies might not take in adequate amounts of oxygen and their bodies might not be able to maintain a normal body temperature, according to the Lucile Packard Children's Hospital at Stanford. Low birth-weight babies can have a hard time feeding, too. Babies born with low birth weight are also at a higher risk for infection, respiratory problems, bleeding in the brain, intestinal problems and sudden infant death syndrome.

Dangers in Adulthood

A baby born with a low birth weight can experience health problems into adulthood. Adults who were classified as low birth weight are at a higher risk for high blood pressure, type 2 diabetes and heart disease, In fact, according to the March of Dimes, men who weighed less than 6 1/2 pounds at birth were up to 10 times more likely to have those conditions, collectively known as metabolic syndrome 2. Though more research is necessary to determine why that is so, researchers suspect that growth restriction in utero can negatively affect the development of certain organs such as the heart and liver.


Not all cases of low birth weight can be prevented, but pregnant women can take steps to reduce the risk. Getting adequate prenatal care is essential because it allows an obstetrician to identify potential problems early enough that treatment can be effective. An obstetrician can also provide care for chronic health conditions in the mother that contribute to low birth weight. Taking at least 400 micrograms of folic acid each day during pregnancy can also reduce the risk of low birth weight. Not smoking is another way to lower the risk, according to the March of Dimes 2.