Antenatal Steroids: Supporting Healthy Outcomes for Preterm Infants

Introduction

Antenatal steroids are a vital intervention in the management of preterm births. These steroids, primarily betamethasone and dexamethasone, are used to accelerate the development of fetal organs, particularly the lungs, when there is a risk of premature birth. Administering antenatal steroids to women at risk of preterm labour has been shown to significantly reduce neonatal complications such as respiratory distress syndrome (RDS), intraventricular haemorrhage (IVH), and necrotising enterocolitis (NEC), improving overall survival rates for premature infants.

This article provides a detailed exploration of antenatal steroids, focusing on the timing, dosage, and effects of the treatment, along with insights into its role in pregnancy care and the importance of antenatal appointments. Understanding these aspects is crucial for expectant parents and healthcare providers to ensure the best outcomes for both mother and baby.

What Are Antenatal Steroids?

Antenatal steroids refer to a class of corticosteroids, most commonly betamethasone and dexamethasone, used during pregnancy to promote the maturation of the fetus’s organs, especially the lungs. The primary mechanism of action of antenatal steroids is to accelerate the production of surfactant, a substance produced in the lungs that helps the alveoli (tiny air sacs) stay inflated and facilitates proper breathing after birth.

In preterm infants, the lungs are often underdeveloped, leading to difficulty breathing and conditions such as respiratory distress syndrome (RDS). Antenatal steroids improve fetal lung development, reducing the risk of RDS and improving the chances of survival for preterm infants. These steroids are usually administered in two doses, 24 hours apart, and are typically administered between 24 and 34 weeks of gestation, when the fetus’s lungs are most responsive to the treatment. (Royal College of Obstetricians and Gynaecologists, 2023)

Timing and Dosage of Antenatal Steroids

1. When Are Antenatal Steroids Administered?

The primary purpose of antenatal steroids is to enhance fetal lung development in women at risk of preterm labour. These steroids are most effective when given between 24 and 34 weeks of gestation. However, they can be administered later in pregnancy if there is a significant risk of preterm birth, though the benefits may diminish after 34 weeks when the lungs are generally more mature.

Antenatal steroids are typically given to women who:

Show signs of preterm labour before 34 weeks of gestation.

Have preterm premature rupture of membranes (PPROM), where the membranes rupture prematurely but labour has not yet started.

Are carrying multiple babies, as they are at higher risk of preterm birth.

For optimal effectiveness, antenatal steroids are administered within 24-48 hours before birth, ideally in a hospital setting under the supervision of medical professionals. (American College of Obstetricians and Gynecologists, 2023)

2. Dosage and Administration

The typical dosage of antenatal steroids consists of two doses, given 24 hours apart. The exact dosage varies based on the steroid used. For betamethasone, the standard regimen involves 12 mg given intramuscularly twice, 24 hours apart. For dexamethasone, the usual dose is 6 mg every 12 hours for four doses.

The steroid injections are administered in the gluteal muscle, and the medication crosses the placenta to take effect in the fetus. Within 24 to 48 hours of receiving antenatal steroids, the fetus’s lungs begin to produce more surfactant, and the baby’s chances of surviving and thriving after birth improve significantly. (Mayo Clinic, 2023)

The Benefits of Antenatal Steroids

1. Improving Lung Function in Preterm Infants

Respiratory distress syndrome (RDS) is one of the most common and severe complications faced by preterm infants. Antenatal steroids significantly reduce the incidence of RDS by promoting the production of surfactant in the fetus’s lungs. Surfactant helps keep the tiny air sacs in the lungs open, facilitating effective gas exchange after birth. By improving lung function, antenatal steroids help preterm infants breathe more easily and reduce the need for mechanical ventilation.

Studies have shown that antenatal steroids can reduce the incidence of RDS by as much as 50%, offering a substantial improvement in the survival and health of preterm infants. (National Institutes of Health, 2023)

2. Reducing Other Preterm Birth Complications

In addition to improving lung function, antenatal steroids reduce the likelihood of other complications associated with preterm birth, such as:

Intraventricular haemorrhage (IVH): Bleeding in the brain, which is particularly common in extremely preterm infants.

Necrotising enterocolitis (NEC): A serious gastrointestinal problem that affects preterm infants.

Patent ductus arteriosus (PDA): A heart condition that occurs when the ductus arteriosus fails to close after birth.

By stimulating the development of various fetal organs, antenatal steroids help reduce the risk of these life-threatening conditions, improving the overall health outcomes for preterm infants. (Royal College of Obstetricians and Gynaecologists, 2023)

3. Long-Term Benefits for Preterm Infants

The benefits of antenatal steroids extend beyond the immediate neonatal period. Research suggests that preterm infants who were exposed to antenatal steroids in utero tend to have improved long-term health outcomes, such as better motor skills, cognitive function, and fewer behavioural problems.

For instance, studies have found that infants who received antenatal steroids are less likely to develop cerebral palsy and experience developmental delays. These long-term benefits highlight the importance of antenatal steroids in not only saving lives but also improving the quality of life for preterm infants as they grow. (Mayo Clinic, 2023)

The Risks and Side Effects of Antenatal Steroids

1. Potential Risks for the Mother

The primary side effect for the mother is elevated blood sugar levels, particularly in women who have gestational diabetes or pre-existing diabetes. Elevated blood sugar can be a concern, but this effect is usually temporary and resolves once the steroids are no longer administered.

Another potential risk is immune suppression, which may slightly increase the risk of infections in the mother. However, the risk of these side effects is low, and healthcare providers carefully monitor women receiving antenatal steroids to manage any complications. (American Pregnancy Association, 2023)

2. Potential Risks for the Baby

The potential long-term effects of antenatal steroids on the baby are still being studied. Some research suggests that infants exposed to antenatal steroids may have a slightly increased risk of asthma and wheezing in childhood. However, these effects are minimal compared to the benefits of preventing severe preterm birth complications like RDS.

Furthermore, while there is some concern regarding developmental or behavioural effects, studies generally indicate that antenatal steroids do not have significant long-term negative impacts on the child. (American College of Obstetricians and Gynecologists, 2023)

The Role of Antenatal Care in Preterm Birth Management

Antenatal care is essential for managing pregnancies at risk of preterm birth. Regular antenatal appointments, antenatal checkups, and antenatal scans help healthcare providers monitor the health of both the mother and the baby. Early detection of preterm labour signs, such as cervical changes or preterm contractions, allows for timely interventions like antenatal steroids.

Expectant mothers at risk of preterm birth can also benefit from emotional and psychological support, as the stress of a high-risk pregnancy can affect both maternal and fetal health. Techniques such as antenatal yoga, pregnancy massage, and other forms of antenatal fitness can help manage stress and improve overall well-being during pregnancy. (My Expert Midwife, 2023)

Conclusion

Antenatal steroids are an essential intervention in the management of preterm labour, significantly improving neonatal health outcomes. By promoting lung development and preventing complications like respiratory distress syndrome (RDS), antenatal steroids help ensure that preterm infants have the best possible chance of survival and a healthy life.

While antenatal steroids come with some risks, such as elevated blood sugar in the mother and potential long-term respiratory issues in the child, the benefits far outweigh these concerns when administered correctly and under careful medical supervision. Expectant parents should work closely with their healthcare providers to understand the role of antenatal steroids, their timing, dosage, and effects, as well as the broader aspects of antenatal care necessary for a healthy pregnancy.