A premature infant is a baby born before 37 weeks gestation.

At birth, a baby is classified as one of the following:

• Premature (less than 37 weeks gestation)
• Full term (37 to 42 weeks gestation)
• Post term (born after 42 weeks gestation)

If a woman goes into labor before 37 weeks, it is called pre-term labor. Often, the cause of pre-term labor is unknown. Multiple pregnancy (twins, triplets, etc.) makes up about 15% of all premature births.

The following health conditions and events in the mother may contribute to pre-term labor:

• Preeclampsia
• Kidney disease
• Diabetes
• Infection
• Heart disease
• Lack of prenatal care
• Poor nutrition
• Young age (a mother age younger than 18)
• Substance abuse

A woman who has had any of the following is at increase risk of pre-term labor:

• Previous pre-term delivery
• Unexplained high alpha-fetoprotein level in the second trimester
• Untreated disease or infection (such as urinary tract infection or infection of the amniotic membranes)
• Problems with the uterus or cervix
• Premature rupture of the membranes or placenta previa

A premature infant has organs that are not fully grown. The infant needs special care in a nursery until the organ systems have developed enough to sustain life without medical support. This may take weeks to months.

A premature infant will have a low birth weight - less than 5.5 pounds (2500 grams). Common symptoms in a premature infant include:

• Respiratory problems such as hyaline membrane disease (also known as respiratory distress syndrome or RDS)
• Episodes of absent breathing (apnea)
• Poor feeding
• Thin, smooth, shiny, almost translucent skin
• Transparent skin (can see veins under skin)
• Wrinkled features
• Soft, flexible ear cartilage
• Body hair
• Weak cry
• Usually inactive -- however, may be unusually active immediately after birth
• Enlarged clitoris (female infant)
• Small scrotum, smooth without ridges (male infant)

This list may not be all inclusive.

The infant may have a low body temperature and show signs of breathing problems.

Common tests performed on a premature infant include:

• Chest x-ray
• Blood gas analysis
• Blood tests to check glucose, calcium, and bilirubin levels