The reason why 37 weeks is no longer considered full term is because of extensive medical research that has revealed that babies that are born between 37 weeks to 39 weeks, face significantly higher health risks than babies that are born at 39 weeks or later.
The medical community for decades has grouped all deliveries between 37 weeks and 42 weeks under the broad umbrella of "term", and assumed babies that were born within this 5 week window had identical health outcomes.
But now, studies show that every week counts and in the year 2013, major medical organizations, which also includes the American College of Obstetricians and Gynecologists and the Society for Maternal Fetal Medicine now officially updated the definitions to better protect health of newborns.
The old 5 week window was broken down into 4 distinct categories to provide more accurate clinical care.
Early Term is 37 weeks 0 days through 38 weeks 6 days.
Full term is 39 weeks 0 days through 40 weeks 6 days.
Late Term 41 weeks 0 days through 41 weeks 6 days.
Postterm 42 weeks 0 days and beyond.
The extra 2 weeks matter because a baby's body undergoes crucial final developments during the last couple of weeks of pregnancy.
Important physiological milestones that occur between weeks 37 and 39 include, brain growth, lung maturity, feeding reflexes and fat and temperature regulation.
A baby's brain when they are only at 35 weeks weighs only around 65 percent of what it will weigh at 39 weeks to 40 weeks, which means that critical neurological pathways and connections are still forming during the early term period.
The production of surfactant, which is the compound that allows your lungs to expand and breathe independently outside of the womb, increases significantly during the final weeks.
And brain and nerve connections that are needed to coordinate sucking, swallowing and breathing simultaneously are also fully mastered closer to 39 weeks.
And early term babies are often too sleepy or weak to feed efficiently.
In the final weeks, babies also accumulate essential layers of body fat and without this fat, early term babies struggle to regulate their own body temperature.
Babies that are born at 37 weeks to 38 weeks are more likely to face complications when compared to full term infants.
These risk that babies born at 37 weeks to 38 weeks face are higher rates of admission to the Neonatal Intensive Care Unit, Increased risk of respiratory distress and breathing difficulties, higher chances of feeding difficulties and jaundice and increased susceptibility to blood infections.
The warning signs of preterm labor are contractions that occur every 10 minutes or more than 6 contractions in an hour, pelvic pressure or feeling like the baby is pushing down, low dull backache, abdominal cramping, with or without diarrhea and vaginal discharge changes or bleeding.
If you experience any signs of preterm labor you should go to the hospital immediately or call your doctor.