Low Birthweight
Percentage of live births where children weigh 2,499 grams (5.51 lbs.) or less.
Why did we include this measure?
Low birthweight is associated with a wide range of short-term issues for infants and longer-term issues later in life, including developmental delays, chronic health issues, behavioral and emotional problems, and stunted physical growth.
How does the US rank globally?
- Specific Measure: Percentage of live births with babies weighing under 2,500 grams.
(Source: Authors’ analysis of UNICEF data).
- Percentage of countries the US outperforms: 50% (out of 101 countries)
- International Rank Trend: Stable
National Trend Worsening
What do the data show?
While the overall rate may seem low, the rate of low birthweight has been steadily rising, and we are only in the middle among high-income countries. Our international standing has remained relatively steady. Slovakia, Uruguay, and Luxembourg currently rank just above us. The top-ranked country, Iceland, has a rate that is less than half the US rate.
What might explain these patterns?
Some of the rise in low birthweight is driven by the rising age at which women are having children. Also, the rising use of assisted reproduction (e.g., in vitro fertilization, IVF) leads to a greater prevalence of multi-child births where each baby generally has a lower birthweight. Low birthweight is also related to mothers’ obesity, malnutrition, sexually transmitted diseases, stress, and substance abuse, which are related to a mix of behaviors, habits, policies, and socio-economic conditions. One of those conditions is poverty. While our measure of poverty is declining, this might not be the case among pregnant women and poverty measures do not capture access to health care very well. A lack of prenatal health care, especially among lower income groups, may contribute to these and other issues that cause low birthweight.
For more information about data sources and treatments, download the Data Notes.