Preterm birth is a growing public health concern globally. It is defined as a delivery before 37 completed weeks of gestation. Premature babies are more susceptible to infections due to their weak immune system.

However, recent studies suggest that preemies have a superior immune system in the long run as compared to full-term babies. This article will explore how and why preemies have stronger immune systems in the long run.

What is a Preemie?

A preemie, also known as a premature baby, is born before 37 weeks of gestation. There are three categories of preterm birth based on gestational age:.

Extremely preterm: born at or before 25 weeks
Very preterm: born between 26 and 31 weeks
Moderate to late preterm: born between 32 and 36 weeks

Preterm birth can occur spontaneously or due to medical intervention to save the life of the mother or the baby. The causes of preterm birth are not entirely clear, but some risk factors include:.

Infections during pregnancy
Multiple pregnancies (twins, triplets, etc.)
Chronic health conditions such as high blood pressure or diabetes
Stress
Age (too young or too old)

Why Are Preemies More Susceptible to Infections?

Preemies have a weak immune system due to several factors:.

Their immune system is not fully developed
Their skin is thin and fragile, making it easier for germs to enter their body
Their lungs are not mature, making them more susceptible to respiratory infections
Their gut is still developing, and they do not have enough good bacteria to fight off bad bacteria
They may undergo medical procedures such as intubation, intravenous lines, or surgeries, which increase the risk of infections

Preemies are often hospitalized for weeks or months in a neonatal intensive care unit (NICU) where they are monitored and treated for various conditions.

However, the NICU is also a breeding ground for infections due to the close proximity of preemies, the use of medical equipment, and the presence of bacteria.

What Are the Long-Term Health Consequences of Prematurity?

Prematurity can have long-term health consequences for babies, including:.

Respiratory problems, such as asthma or chronic lung disease
Neurological problems, such as cerebral palsy or learning disabilities
Growth and development problems, such as delayed motor skills or speech
Vision and hearing problems
Chronic health conditions, such as diabetes or cardiovascular disease

Prematurity can also affect the mental health and wellbeing of families, as they may experience financial, emotional, and social stress.

Why Do Preemies Have Stronger Immune Systems in the Long Run?

Despite the increased susceptibility to infections, preemies have a stronger immune system in the long run as compared to full-term babies. The reasons for this are still being studied, but here are some possible explanations:.

Exposure to Germs in the NICU

Preemies are exposed to a wide range of bacteria, viruses, and fungi in the NICU. While this may increase their risk of infections, it also stimulates their immune system to produce more immune cells and antibodies to fight off these invaders.

This exposure may also help their immune system recognize and remember these germs in the future, making them less susceptible to infections later in life.

Delayed Cord Clamping

Delayed cord clamping is a practice where the umbilical cord is not clamped or cut immediately after birth. Instead, the baby is allowed to receive blood from the placenta for a few minutes or until the cord stops pulsating.

This practice has been shown to increase the baby’s blood volume and iron stores, which can support the development of their immune system and reduce the risk of anemia. Some studies have also suggested that delayed cord clamping may improve the baby’s immune function, including the production of T-cells and natural killer cells.

Breastfeeding

Breast milk is rich in antibodies, immune cells, and other bioactive factors that can boost the baby’s immune system.

Preemies who receive breast milk, especially their mother’s own milk, have a lower risk of infections, necrotizing enterocolitis (NEC), and other health problems. Breast milk helps to colonize the baby’s gut with good bacteria, such as lactobacillus and bifidobacterium, which can protect against bad bacteria and support the immune system.

Breastfeeding also has long-term benefits for the baby’s health, such as reducing the risk of obesity, allergies, and autoimmune diseases.

Epigenetic Changes

Epigenetics refers to the changes in gene expression that are not caused by changes in the DNA sequence itself but by external factors such as environment, diet, and lifestyle.

Preemies may undergo epigenetic changes due to their exposure to intrauterine stress, premature delivery, and neonatal care. Some studies have suggested that these changes may result in alterations in the immune system that can either increase or decrease the risk of infections and other diseases.

For example, a study published in Nature Communications in 2020 found that preemies had a different epigenetic profile in their immune cells as compared to full-term babies, which may affect their immune function in the long run.

Maternal Immunity

Preemies may receive some passive immunity from their mother during pregnancy, especially if the mother has been vaccinated or exposed to certain infections.

This immunity can protect the baby from some diseases in the first few weeks of life until their own immune system is fully developed. Some studies have suggested that this maternal immunity may also stimulate the baby’s immune system to produce more immune cells and antibodies, which can enhance their immune function later in life.

Conclusion

Preemies are at higher risk of infections due to their weak immune system, but they also have a superior immune system in the long run as compared to full-term babies.

The reasons for this are still being explored, but exposure to germs in the NICU, delayed cord clamping, breastfeeding, epigenetic changes, and maternal immunity are some of the possible explanations. Understanding the immune system of preemies and how it develops can help healthcare professionals provide better care and support for both preemies and their families.