A premature birth means that your baby hasn't had the usual amount of time to develop in the womb before needing to adapt to life outside the womb.

The signs that a baby's gestation has been cut short include:

  • Small size, with a disproportionately large head
  • Sharper-looking, less rounded features than a full-term baby's features
  • Thin, transparent, fragile-looking skin
  • Fine hair (lanugo) covering much of the body
  • Low body temperature, especially immediately after birth in the delivery room
  • Labored breathing or respiratory distress
  • Lack of reflexes for sucking and swallowing, leading to feeding difficulties

The following table shows the median weight, length and head circumference of premature babies at different gestational ages.

Weight, length and head circumference by gestational age
Gestational age Weight, in pounds (kilograms) Length, in inches (centimeters) Head circumference, in inches (centimeters)
40 weeks 7.9 (3.6 kg) 20 (51 cm) 14 (35.5 cm)
35 weeks 5.6 (2.5 kg) 18.1 (46 cm) 12.6 (32 cm)
32 weeks 4.2 (1.9 kg) 16.9 (43 cm) 11.8 (30 cm)
28 weeks 2.5 (1.15 kg) 15 (38 cm) 10.2 (26 cm)
24 weeks 1.4 (0.65 kg) 12.6 (32 cm) 8.7 (22 cm)

Premature babies can quickly develop serious complications, such as infection in the bloodstream (sepsis), respiratory distress syndrome and bleeding in the brain.

When to see a doctor

You'll be seeing members of the neonatal intensive care unit (NICU) often. Most NICUs have work rounds at a similar time each day, which parents may join. Don't hesitate to ask questions even when there's not a regularly scheduled meeting, especially if your baby seems listless, has poor color or refuses the bottle or breast after trouble-free feedings.

Dec. 29, 2011