10 Facts About Preterm Birth

Today is World Prematurity Day, so I thought I’d compile some interesting facts about preterm birth (at least I found them interesting and I hope you do too!)


  • Preterm birth is defined as birth before 37 weeks gestation. There are different sub-categories of preterm birth depending on how far long into the pregnancy the birth happens:

Extremely preterm: birth before 28 weeks
Very preterm: birth between 28 weeks - 32 weeks
Moderate to late preterm: 32 weeks to 37 weeks (Preterm Birth Research Initiative)

  • Around 70% of the time there is no known cause for a preterm birth. Some common reasons include being pregnant with multiples, infections, diabetes, high blood pressure, and cervical incompetence.
  • Preterm babies are often evaluated based on their “adjusted age,” which is calculated by subtracting the difference between the birth date and the due date from the chronological age. For example, Anna is 12 weeks old. She was born at 32 weeks. Her adjusted age would be calculated as follows:

12 weeks - (40 weeks - 32 weeks) = Anna’s adjusted age is 4 weeks old

  • Worldwide, the rate of preterm birth ranges from 5% to 18%, with Canada falling on the lower end at 8% overall.
  • Within Canada itself the rate of preterm birth varies (remember, this is a huge country!). In PEI, the rate is the lowest at 6%, while Nunavut has the highest rate at 10%.
  • Preterm birth accounts for up to 85% of all perinatal deaths in Canada (which includes stillbirths and deaths of infants less than 7 days old). 
  • According to the World Health Organization, preterm birth complications are the leading cause of paediatric death under 5 years of age, accounting for nearly 1 million deaths in 2015 worldwide. 
  • Of those, it is estimated that 3/4 of babies lost to prematurity could be saved with the right medical technology readily available in high-income countries like Canada, including things as relatively common as steroid injections for premature lungs, incubators, respiratory aids, antibiotics, and access to breastmilk. 
  • Survival rates vary by gestational age: at 25 weeks babies have an 80% chance of survival, and by 32 weeks onwards the majority of babies will survive. Every week counts in utero!
  • The good news: in Canada, the outlook for premature babies is very good due to the medical resources we have here. Most very preterm, and moderate to late preterm babies, have no developmental or cognitive delays compared to their full-term counterparts.

The best way to prevent preterm birth is good prenatal care. Check in with your health-care provider as scheduled to catch any problems early, maintain a healthy diet, and try to stay as stress-free as possible.

And remember, the above are statistics based on group data and do not take into consideration individual babies. Every child is different.

If you have a preterm birth story, I’d love to hear it - just pop it into the comments below <3


Canadian Premature Babies Foundation


Preterm Birth Research Initiative
Canadian Institute for Health Information
March of Dimes
World Health Organization
Manual of Neonatal Care