An average newborn usually weighs approximately 8 pounds. Babies gain much of their weight during the last weeks of pregnancy. Because of this, low birthweight can be caused by premature birth (before 37 weeks of pregnancy).  

Another cause of low birthweight is called intrauterine growth restriction (IUGR). This condition occurs when a baby does not grow well during pregnancy. It may be because of problems with the placenta, the mother’s health, or the baby’s health.

Healthy birth spacing helps prevent low birth weight. Healthy birth spacing generally calls for 18-24 months between pregnancies.  

Several factors impact infant birthweight, including but not limited to environmental stressors, the mother’s access to proper nutrition, stress levels, and ability to receive regular prenatal care. 

The consequences for low birthweight infants can be severe and include respiratory distress syndrome, bleeding in the brain, intestinal issues, and damage to the retina. Later in life, these complications can lead to diabetes, blindness, deafness, heart disease, and breathing problems, among several other conditions.

The data show that Black women are twice as likely to have a low birthweight baby than white women. Research designed to control for environmental factors has found that this disparity exists due to the effect of weathering. The weathering hypothesis states that chronic exposure to social and economic disadvantage leads to an accelerated decline in physical health outcomes and could partially explain racial disparities in a wide array of health conditions. This historical and institutionalized trauma negatively impacts both the mother and baby’s health.