Prematurity affects more than 15 million babies each year worldwide. In Brazil, approximately 30% of births are premature and prematurity is one of the main causes of admission to neonatal intensive care units.
Among experts, there is a perception that this number is increasing due to several factors, including the increase in multiple pregnancies, chronic illnesses of pregnant women, and specific conditions of pregnancy. To better understand this scenario, as well as the possible consequences of prematurity on the future of the child, as well as ways to prevent it, O GLOBO spoke with the gynecologist and obstetrician, Bruno Alencar, director of Perinatal, in Rio de Janeiro. Check out the full interview.
What is the definition of prematurity?
Prematurity refers to any baby born before 37 weeks. Then, between the ages of 37 and 42, that’s what we call a full-term baby. This “trimester” period is subdivided into the beginning of the trimester, between 37 and 39 weeks; the ideal term, which is 39 to 41 weeks, and the late term, which is after 41 weeks, which has a lot of impact on neonatal intensive care admissions, especially compared to Brazil or countries that have very high cesarean section rates.
Could you better explain why?
We end up performing elective cesarean sections on patients considered full term because they are already past 37 weeks. But during this time, babies are not yet as mature and end up needing to be admitted to the neonatal intensive care unit to undergo breathing adaptation because they were removed before the ideal time. This is also a significant proportion and, unfortunately, a negative point in a country where many elective cesarean sections are still performed, without labor, without absolute indication, and end up leading to more admissions to neonatal intensive care.
Is prematurity increasing in Brazil?
Yes, prematurity is increasing in Brazil and around the world due to several factors. One of the main ones today is the change in the mother’s age. In the past, women had children younger, in their late 20s or early 30s. Today, we see that women have children after 35, 37, 38 years old. Last year, I had three births over the age of 50, for example. Unfortunately, with age comes an increased risk of complications. A more mature woman is at greater risk of suffering from high blood pressure during pregnancy and diabetes, diseases that eventually cause premature birth. Another thing is the increase in the number of children resulting from in vitro fertilization. In vitro fertilization, although it is very advanced and has significantly improved outcomes, is also associated with increased clinical risk, increased placental insufficiency, high blood pressure and even diabetes. Therefore, women who have undergone in vitro fertilization must benefit from stricter prenatal care.
Are there other risk factors that increase the risk of prematurity?
Clinical diseases, mainly diabetes and pre-eclampsia – which is hypertension of pregnancy – are closely associated with prematurity. In gestational diabetes, when identified early and well controlled, we can carry the pregnancy to term. Preeclampsia, which is high blood pressure, also tends to be controlled, but not as well as diabetes, because preeclampsia is a disorder of the placenta and, unfortunately, it always tends to get worse. So our job as an obstetrician with a patient with hypertension is to try to get her as far as possible without posing a risk to the baby. There are also other mechanical situations that increase the risk, such as uterine malformations, those who have undergone cervical surgery. Other situations are more common, such as a urinary infection, which is an important factor in triggering premature birth because a bladder infection can generate a uterine infection which triggers a contraction or break of the waters.
But shouldn’t this warning come from the doctor himself, even if the pregnant woman wants to schedule the delivery during this period?
Yes. It is the obstetrician’s duty to protect the baby as well. In prenatal care, I talk a lot with my patients. Sometimes, the patient arrives at the end of pregnancy tired because of the weight of her stomach, numerous heartburns, shortness of breath and the desire to urinate frequently. So they ask “for the love of God, deliver me, I can’t take it anymore”. But I emphasize that I have a duty towards the baby, towards his maturity. Thus, to carry out a delivery on demand, and specifying that this is now considered ethical by the Federal Council of Medicine and the Society of Gynecology and Obstetrics, good practice dictates that this should only be done after 39 weeks. In this way, we have a better guarantee of maturity of the respiratory system, which is the last thing to be ready before birth. Sometimes the baby is ready, has a good weight and everything, but the lungs are not yet fully mature and they have difficulty adapting when they come to breathe the surrounding air. When we do this after 39 weeks, there is a greater chance that the baby will not need respiratory support.
Is it possible to prevent premature birth?
The best prevention is good prenatal care. I think that there is no other action to date in the care of pregnant women that has had as much impact on improving maternal and neonatal mortality as prenatal consultation. In the case of urinary tract infections, for example, which are a common condition in women and even more so in pregnant women, it is very important to carry out periodic urine tests and examine the patient to see if she has vaginitis, discharge or vaginal irritation that could cause a urinary or uterine infection to avoid premature birth.
And what would be a good prenatal period?
Good prenatal care means being able to have at least 7 to 10 visits during pregnancy, having periodic blood and urine laboratory tests, and having your blood pressure and blood sugar measured. If you do this periodically during the 9 months of pregnancy, you will ensure that the doctor will be able to identify any changes in your health early, thus being able to act and treat you to avoid premature delivery.
What are the risks of premature birth for the baby but also for the mother?
A smaller baby has less defense. He does not yet have a fully developed immune or respiratory system. He is therefore more at risk of infection, he needs more support to feed because he still does not have the strength to suckle. Sometimes they don’t have the strength to breathe. We use the intercostal muscles to breathe, we expand the chest. The baby, who is very small and weaker, gets tired of breathing because his muscles are not well developed. So you need respiratory assistance. And anything we need to invade increases the risk of infection and hemorrhage. For the mother, the risks are more related to the cause of the premature birth than to pre-birth, diabetes or uterine infection. And there is also a slight increase in risk from the delivery itself, when it is a cesarean section because as the uterus is not yet fully dilated, there is a greater risk of bleeding than a cesarean section in a full-term uterus because it is more distended, it is thinner and easier to open.
Does prematurity leave consequences for the child?
This is where the issue of perinatal care comes into play. There must be a neonatal intensive care unit that can provide multidisciplinary care to this baby so that it has no consequences and, today, this is completely normal. There is a whole team that will take care of this baby, that will feed him, that will help him breathe, that will prevent infections, that will hydrate him so that when he reaches the ideal point, he can come out without any consequences. The conditions for leaving a baby at home are to weigh more than 2 kg, to be able to breastfeed alone and to breathe ambient air.
Do all premature babies go to neonatal intensive care?
Yes, because premature babies require more rigorous monitoring, and we can only ensure this in neonatal intensive care. When we talk about critical care, we always think of complexity. But the neonatal ICU is organized into clusters. So we have babies with higher severity, medium severity and low severity. For example, a baby born at 35 weeks weighs 1.8 kg and undergoes an adaptation, mainly at the digestive level and breathes the same air that we breathe. And there is a 27-week-old baby who weighs 750 grams and needs help breathing with a tube, parenteral nutrition or has a gastrostomy. They are therefore in different environments within the neonatal ICU, where the care needs of each patient are distributed.
In your opinion, what advances have helped the most on the issue of prematurity?
I would say there are two paths. The first concerns the care itself provided in the neonatal intensive care unit. The success rate of neonatal intensive care units today is much better and higher than it was 10 or 20 years ago. Today, when I receive a 1 kg baby, I know that its survival rate is very high compared to what it was 15 years ago. For example, for a baby born at 25 weeks, the survival rate in the 1990s was 40%. Today, it’s 70%, according to data from the Vermont Neonatology Network. This is important because it has improved care in neonatal intensive care units, improved the equipment we have, and improved knowledge about nutritional and ventilatory support. This makes a big difference in the outcome of a premature baby. And the second thing we have improved is obstetric care. Today we have the ability to perform more tests to identify the risk of premature birth, including blood tests, ultrasounds and even amniotic fluid tests, to understand the maturity of the baby, lung tests of the baby to try to reduce the risk of premature birth.
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