What Are the Four Stages of Prematurity in the NICU?
While any baby born before 37 weeks of pregnancy is considered a preemie, there are technically four different stages of prematurity.
Late preterm
Moderately preterm
Very preterm
Extremely preterm
All preemies have different needs, but their gestational timing often determines the severity of their medical issues. For example, a 28-weeker will have different problems than a 34-weeker. A baby born at 34 weeks will also have a greater chance of reaching developmental milestones without requiring intervention.
Fortunately, we live in a time in which even extremely preterm babies are more likely to survive than they would have 10 or 20 years ago. Thanks to medical advances like the use of surfactant to aid lung development, steroids in pregnant mothers, CPAP devices, and enhancements to make the NICU atmosphere more “womb-like,” survival rates are steadily climbing.
Still, not all preterm births are created equal, so it’s important to understand each stage of prematurity and its associated risks.
What Causes Premature Labor?
Before we discuss the stages of prematurity, let’s examine what causes premature labor in the first place.
Contrary to popular belief, preventing a preterm birth is not always straightforward. While we can be aware of risk factors and symptoms, the true causes of premature labor are often complex.
According to Mayo Clinic, there are a number of conditions that make a mother more susceptible:
Previous preterm labor or premature birth, particularly in the most recent pregnancy or in more than one previous pregnancy
Pregnancy with twins, triplets, or other multiples
Shortened cervix
Problems with the uterus or placenta
Smoking cigarettes or using illicit drugs
Certain infections, particularly of the amniotic fluid and lower genital tract
Some chronic conditions, such as high blood pressure, diabetes, autoimmune disease, and depression
Stressful life events, such as the death of a loved one
Too much amniotic fluid (polyhydramnios)
Vaginal bleeding during pregnancy
Presence of a fetal birth defect
An interval of less than 12 months — or more than 59 months — between pregnancies
Age of mother, both young and older
Black, non-Hispanic race and ethnicity
As you might notice, many of these factors are out of our control. Part of reducing the stigma around premature labor is understanding that unless a mother explicitly chooses to put her baby in harm's way while she is pregnant, her preterm birth is not her fault.
One out of every ten births is premature. It is not uncommon for the women in our lives to experience this. When and if it happens, it’s important to extend grace, understanding, and love. The more background knowledge we have about preterm birth, the more helpful and empathetic we can be to our loved ones.
Late Preterm
The first stage of prematurity is late preterm. This subsection of babies is represented by those born between 34 and 36 weeks of completed pregnancy.
They also make up the majority of preterm births. If your baby is born late preterm, they have a high likelihood of survival–nearly 100%.
According to a study published in the American Journal of Perinatology, moderate to late preterm babies with no significant medical problems on admission are likely to be discharged at 36 weeks of postmenstrual age (gestational age plus age since birth). In other words, they will not have to spend as much time in the NICU.
Moderately Preterm:
The second stage of prematurity is moderately preterm. These are babies born between 32 and 34 weeks. They also have a high likelihood of survival, hovering at about 99%.
Technically, babies born before 34 weeks are most likely to have long-term health problems.
Very Preterm:
Very preterm babies are born at less than 32 weeks. In this stage of prematurity, the survival rate is between 80-90%. Babies born at 28 weeks have a 10% chance of developing long-term health problems.
My daughter Jenna was born at 28 weeks and was in the NICU for 77 days. Thanks to our care team of doctors, nurses, and therapists, she has made huge strides and is now a thriving five-year-old girl.
The good news is that very preterm babies still have a strong chance of success–physically, emotionally, and developmentally. As stressful as it can be to have a child in the NICU, it’s encouraging to know that with the right support, they can grow into happy and resilient individuals!
Extremely Preterm:
An extremely preterm baby is born at or before 25 weeks of completed pregnancy. These children have the lowest likelihood of survival and the highest risk of disability.
According to an article by the University of Utah Health, “Infants that are born very early are not considered to be viable until after 24 weeks gestation. This means that if you give birth to an infant before they are 24 weeks old, their chance of surviving is usually less than 50 percent.”
Before 24 weeks, their lungs and vital organs aren’t developed enough yet. The survival rate for a 24-week-old is between 60 and 70%. It’s amazing how just a couple extra weeks in the womb can decrease the odds of mortality and long-term health issues.
Still, the advances in neonatal care have allowed more and more extremely preterm babies to be able to survive.
Why Do the Four Stages of Prematurity Matter?
You might be wondering, “Aren’t these categories kind of arbitrary?” Aside from the differences we’ve discussed above, grouping preemies into the different stages of prematurity helps facilitate research and clinical prevention strategies.
Right now, the majority of research has been dedicated to very preterm babies–not as much to other groups. If doctors and researchers can further clarify the spectrum of mortality and long-term health issues, we can better understand what preemies need to thrive at their respective stages.
It also helps us, as parents, find and relate to other moms and dads who are in a similar situation. Just like preemie families shouldn’t be lumped together with full-term families, having an extremely preterm baby shouldn’t be lumped together with the experience of having a late preterm baby. The feelings and journeys are different.
All NICU experiences are valid, but it’s crucial that our needs as parents and our children’s needs are met individually rather than through a one–size–fits–all approach.
If you’re a mom with a child in the NICU, I offer one-on-one coaching, resources, and guides to find more peace and clarity on your journey. You can book a free exploration call here.
If your baby was born late, moderately, very, or extremely preterm, and you believe they need additional services and intervention, you can read my article, “How to Navigate Early Intervention for Your Baby.”