Over 15 million babies are born prematurely, before 37 weeks gestation, across the globe every year. This Prematurity Awareness Month, we need to talk about that — because as all data indicate that more and more babies are preterm, prematurity is a growing public health crisis.
What is a premature birth?
A normal and healthy pregnancy takes just over the famous "nine months" — around 40 weeks. While the first two trimesters of pregnancy are important, a lot of development continues to take place in the third and final trimester. The baby will put on significant amounts of weight during this time, which will allow her to better regulate her body temperature. She will start to open her eyes, and her fingernails will grow. More importantly, her lungs will start to prepare for life outside the uterus.
A baby born before 37 weeks is considered premature or preterm. Those born between 32 and 37 weeks will be late-term preemies, and babies born between 28 and 32 weeks are called very preterm infants. The extremely preterm babies that emerge from the uterus before 28 weeks are most vulnerable and least likely to survive. Even late preterm babies are exposed to a myriad of health risks, and they make up 40 percent of preemies admitted to NICUs.
Survival rates for premature babies differ greatly across the globe
Premature birth is the most common cause of death for children under five, globally, and the World Health Organization notes that more than a million babies and children succumb to complications directly related to premature births each year.
Babies born prematurely in high-income nations are much more likely to survive their early birth — 90 percent of extremely preterm babies in low-income countries die, compared to only 10 percent in the highest-income countries. According to the WHO, more than three quarters could be saved with access to the right care, medications, and life-saving equipment. With proper prenatal care, a significant number of premature births could also be prevented.
Premature births are more common in lower-income settings — while nine percent of babies in high-income countries arrive too early, this figure rises to 12 percent in low-income countries.
What causes premature birth?
Very often, the cause of a spontaneous premature labor (one that starts before the 37th week) remains unknown. However, we know that premature labor can be brought on by medical factors such as infection, a short cervix, smoking during pregnancy, nutritional deficiencies, maternal underweight at the beginning of pregnancy, and carrying twins or multiples. Mothers who have already delivered one baby prematurely are also much more likely to experience another preterm labor in future.
In other cases, premature babies are born after their mothers' labors were induced or after a planned c-section. Doctors may decide to facilitate preterm delivery in the case of conditions such as preeclampsia or placenta previa, in which continued pregnancy would be riskier than delivery for mother and baby. When premature deliveries are planned, the medical team can better prepare for the baby's care, including by offering steroids to mature the baby's lungs more quickly. This advance planning increases the odds of a good outcome.
What health problems are premature babies most likely to suffer from?
In the months right after their births, preemies are vulnerable to a wide variety of complications, each life-threatening. They include pneumonia, sepsis, dangerously low blood glucose levels, seizures, breathing difficulties, and Sudden Infant Death Syndrome. Whether they were born very prematurely or only slightly, some preemies will require months of round-the-clock intensive care before they can go home.
Even if they make it through that difficult initial time, more challenges may await preemies later in life. A quarter of babies born before 25 weeks will have serious physical or intellectual disabilities. Nearly half of people with cerebral palsy were born prematurely, along with almost a fifth of those with intellectual disabilities, and a third of visually impaired people. Premature birth is a major risk factor for cardiovascular disease later in life, including heart attack and hypertension. The risk of stroke and diabetes also rise.
Why are premature births on the rise?
Why? One obvious factor is the fact that more and more people use IVF to conceive — one of the driving factors behind the increase in twin and multiple pregnancies, which are much more likely to result in a premature birth. IVF cannot explain the huge rise in preterm births on its own, though.
Obesity and increasing maternal age are two more factors, as both are associated with preeclampsia, but researchers also acknowledge that the full picture remains unexplored. Hormonal factors and genetic vulnerability to infection may also play roles.