Antenatal Corticosteroids For Expecting Mothers – Benefits and Risks by Dr Lathiesh Kumar Kambham

Pregnancy comes like two sides of the coin, with both happy and risky phases. The risk of preterm birth is one of them. Babies born before the completion of gestation may encounter several problems during their neonatal period. Preterm births may also lead to other developmental difficulties in babies later in life. Hence, expecting mothers must get continuous checks to avoid the risk and conditions associated with preterm birth. In some cases, doctors may want to administer antenatal corticosteroids for expecting mothers.

Conditions like preeclampsia, gestational diabetes, multiple pregnancies, and other infections may lead to preterm delivery. Other than this, the most common causes of preterm delivery can be multiple pregnancies, previous preterm birth, and problems with the uterus and placenta. Preterm neonates are prone to breathing issues because their lungs are underdeveloped, leading to conditions like Respiratory Distress Syndrome. Antenatal corticosteroids vastly reduce the risk of complications in babies during birth.

In This Article

• What Are Antenatal Corticosteroids?
• Why Are Corticosteroids Given in Pregnancy?
• What Do Antenatal Corticosteroids Do to Fetal Lungs?
• When Should Antenatal Corticosteroids be Given?
• Antenatal Corticosteroid Treatment Options
• Benefits From Antenatal Corticosteroids For The Expecting Mother And The Baby
• How Do Antenatal Corticosteroids Enhance Lung Maturation?
• Role of Steroids During Respiratory Distress Syndrome
• How Do Corticosteroids Help in Reducing Neonatal Mortality?
• How Long Do Antenatal Corticosteroids Take to Work?
• Are There Any Risks of Antenatal Corticosteroids?
• FAQ’s

What Are Antenatal Corticosteroids?

Antenatal corticosteroids are the medication given to pregnant women expecting preterm births. It works as a gateway to exit the respiratory troubles and other complications in premature babies.

The antenatal period refers to the time during pregnancy. Any medication used at this phase is called antenatal medication. This could include pregnancy complications and expected preterm births.

Corticosteroids are a group of hormones that work as anti-inflammatory medication. These are the hormones produced by the adrenal cortex (adrenal glands present on the kidneys).

Synthetically made corticosteroids are used for different conditions like asthma, allergic rhinitis, COPD, asthma in pregnancy, and, an anticipated preterm birth pregnancy.

Why Are Corticosteroids Given in Pregnancy?

Corticosteroids during pregnancy majorly reduce the risk of the baby being born with respiratory problems by enhancing fetal lung functioning. Other studies show that taking antenatal corticosteroids under the right supervision reduces the rate of prenatal and perinatal deaths.

While most pregnancies go through a safe phase and women end up giving birth to a full-term healthy baby, sometimes things can turn upside down, leading to complications.

Preterm delivery is one such complication that can bring many problems for babies since their vitals did not have enough. One major trouble that most preterm and very low birth weight babies face is respiratory distress. It requires a lot of effort from the side of neonatologists in helping babies thrive and get through the phase.

Women with multiple gestations and pre-labor rupture of membranes are sometimes at the risk of preterm delivery. Hence, when doctors anticipate a preterm birth, they administer corticosteroids to expecting mothers.

What Do Antenatal Corticosteroids Do to Fetal Lungs?

Antenatal steroids lower the risks preterm babies carry after being born such as Respiratory Distress Syndrome. They enhance the lung maturation and develop the lungs before birth. Developed lungs can handle the change while majorly avoiding the probability of staying in the Neonatal Intensive Care Unit (NICU).

It also lowers the severity of Respiratory Distress Syndrome and air leakage in premature babies which is a resultant effect of immature lungs.

Corticosteroids clearly work well on preterm neonates without showing little effect on their birth weight. Taking antenatal corticosteroids effectively reduces the risk of

• Being on a ventilator due to preterm birth.
• Intraventricular hemorrhage(IVH) due to preterm birth.
• Necrotizing enterocolitis (an intestinal problem in preterm babies).

Necrotizing enterocolitis is an infection caused due to bacteria that leads to the inflammation of the intestinal tissue. An inflamed tissue eventually dies leading to a perforation in the intestine.

The death of the intestinal tissue may lead to a hole through which the bacteria may enter the bloodstream. Administration of antenatal corticosteroids has evidently reduced the risk of contracting necrotizing enterocolitis (NEC) in preterm babies.

When Should Antenatal Corticosteroids be Given?

Antenatal corticosteroids may be given when the doctor suspects or identifies complications in pregnancy that lead to premature births. Premature births bring a plethora of complications to the baby, and your little one might end up in NICU depending on the intensity of the complication.

Respiratory troubles are the most common complication seen in premature babies. However, if doctors anticipate a premature birth, they may administer antenatal corticosteroids to avoid them.

Types of Premature Births

If a pregnant woman completes her 40 weeks of gestation, then that is called a full-term pregnancy. Babies born any time before 37 weeks of gestation fall under the category of prematurity.

There are types of premature births and the babies born according to the classification may require different types of treatments. Premature births are classified into different types like

• Late preterm birth in which the babies are born before 34 to 36 weeks of gestation.
• Moderately preterm birth in which the babies are born before 32-34 weeks of gestation.
• Very preterm birth in which the babies are born before 25 to 32 weeks of gestation.
• Extremely preterm birth in which the babies are born even before the completion of 25 weeks of gestation.

Antenatal Corticosteroid Treatment Options

Single courses of antenatal corticosteroids are given to women between 23 0/7 to 34 6/7 weeks of gestation.  A 34 0/7 weeks to 36 6/7 weeks of gestation may also require a single course of antenatal corticosteroids. They will be administered if the women are at risk of preterm delivery within 7 days. However, there is no uniform recommendation for the dosage.

Doctors may not consider repeating the course if the woman has already completed 14 days and did not deliver. Repetition may not improve the condition of the baby but might lead to adverse effects on the neurological development of the baby. A 12-hour gap is followed, after the first dose of antenatal corticosteroid (dexamethasone) administration.

Women with preeclampsia, gestational diabetes and pre-labor membrane rupture fall under the safe category to be on corticosteroids. Taking antenatal corticosteroids predominantly reduces surfactant usage, a deficiency in premature babies, and is generally required to improve fetal lung functioning. It also reduces the incidences of transient tachypnea which is a common condition in premature babies.

Transient tachypnea is a condition where the inefficiency of the lungs leads to rapid breathing in babies. While the condition may be self-limited, it may potentially lead to the risk of contracting RDS and tachypnea in premature babies.

Benefits From Antenatal Corticosteroids For the Expecting Mother And the Baby

Here is what antenatal steroids do for the mother and the baby.

• Administering single-dose antenatal corticosteroids to women at a higher risk of preterm birth will bring down the chances of fetal death in the first month of birth.
• They also reduce the chances of breathing difficulties due to conditions such as Respiratory Distress Syndrome and the secondary conditions associated with it.
• RDS is associated with long-term hospitalizations for the baby which can result in life-long disabilities. Administering these steroids during pregnancy can help avoid all such complications
• In addition, these steroids enhance lung maturation by increasing the production of surfactants in the fetal stages.
• The administration of these drugs reduces the chances of babies contracting a dangerous intestinal condition called Necrotizing Enterocolitis.
• The requirement of NICU long-term stay can also come down in most cases. Ventilator support may not be needed with timely administration of antenatal corticosteroids.
• These drugs also reduce the occurrence of certain systemic infections.
• In women with gestational diabetes who are at a higher risk for pre-eclampsia, infections, and newborn RDS, administering corticosteroids will reduce the chances of post-birth systemic infections in babies.

[Read : Necrotizing Enterocolitis]

How Do Antenatal Corticosteroids Enhance Lung Maturation?

There are two types of glucocorticoids majorly used as antenatal corticosteroids –

• Betamethasone
• Dexamethasone

Dexamethasone is a widely used medication in India that has the same benefits as betamethasone.

Keeping preterm delivery anticipated women on dexamethasone shows good results in reducing the risks of pulmonary disorders in preterm babies by enhancing lung maturation.

Mechanism of Antenatal Steroids in Enhancing Lung Maturation

A fetal lung development takes place during pregnancy. The changes in the vascular structure of the lungs are vital to decreasing the pulmonary vascular resistance (which resists the blood flow to the heart). This increases the pulmonary blood flow and enhances the lungs for proper functioning. Lungs need surfactant proteins to decrease the surface tension and allow easy gas exchange.

Administration of antenatal corticosteroids helps in the maturation of surfactant proteins that eventually increase the rate of alveolarization by thinning the double capillary loops that allow gas exchange. It will also accelerate the production of type 2 pneumocytes that are required for surfactant production and to maintain alveolar and airway stability.

[Read : 5 Different Phases Of Fetal Lung Development]

Role of Steroids During Respiratory Distress Syndrome

Antenatal corticosteroids play a major role in reducing the risks of preterm birth complications in neonates including RDS.

Preterm babies’ lungs are immature because of the lack of surfactant, which leads to the inability of gas exchange. This results in respiratory distress syndrome or RDS after birth. Such babies may require to be on ventilators for a prolonged time. RDS may also lead to secondary health complications like Bronchopulmonary dysplasia that may occur due to prolonged assisted respiratory treatments.

• Administering antenatal corticosteroids in anticipated preterm births can help reduce the risk of having Respiratory distress syndrome during the first few days of life.
• It will increase the rate of synthesis of alveolar surfactant-producing type II pneumocytes that can greatly stabilize the lungs.
• The change in the vascular structure of the lungs with the formation of soft tissues increases the pulmonary blood flow.
• This results in decreased chances of ventilator and CPAP requirement after birth. All this will apparently reduce neonatal morbidity and mortality rates due to premature birth.

Administration of corticosteroids as a repeated course is still not suggested. But certain outcomes show that a single course administration of antenatal corticosteroids in some women may not be enough to avoid Respiratory Distress Syndrome in their neonates. However, there is little information on this, while evidence shows that repeated course administration may lead to adverse effects.

How Do Corticosteroids Help in Reducing Neonatal Mortality?

Antenatal corticosteroids reduce the probability of respiratory problems in preterm babies. With this, the baby does not have to stay on external breathing support and that reduces the development of secondary complications causing neonatal mortality. How does that happen?

Lungs are the last organs to develop during pregnancy and premature birth hinders proper development and maturation of lungs, resulting in post-birth complications. The administration of antenatal corticosteroids enhances the fetal lungs by accelerating surfactant production and airway stabilization. Through this, the baby will be at reduced risk of developing respiratory complications after birth. It leads to a decreased rate of neonatal mortality.

Preterm births are generally associated with pregnancy complications like pre-eclampsia, gestational diabetes, pre-labor rupture of membranes, and multiple pregnancies. However, women with no such history may also anticipate preterm labor and delivery. In such cases, the birth may result in neonatal death due to many complications that the baby develops. One of them is Respiratory Distress Syndrome, which is a serious breathing complication. It may increase the need for prolonged NICU treatment.

Many babies thrive and get through the phase. But also the timely administration of antenatal corticosteroids can help in bringing down the possibility of babies being born with RDS and other complications.

How Long Do Antenatal Corticosteroids Take to Work?

The first dose of corticosteroids is administered 7 days before expected preterm delivery. The steroid starts functioning after 24 hours of administration. The effect is going to last for 7 days.

The doctors will discuss the dosage and administration of antenatal corticosteroids with the family initially. After getting the consent of the family, with apparent knowledge of possible neonatal morbidity and mortality, doctors will administer the steroids.

There are no potential risks associated with the proper administration of antenatal corticosteroids. It is only beneficial for preterm neonates, as they help in accelerating the lung development.

There are no evident side effects seen due to the administration of antenatal corticosteroids in both the fetus and the mother. However, the repeated dosage is not suggested for patients who already completed the course of it. It may pose unwanted risks to the fetus.

Are There Any Risks of Antenatal Corticosteroids?

The purpose of administering antenatal corticosteroids is mainly about avoiding your baby facing prolonged complications post birth. Antenatal corticosteroids greatly help preterm neonates circumvent the risk of morbidities.

Doctors do not see any potential risks associated with this medication during pregnancy. However, in rare cases, over dosage or repeated courses may lead to certain problems like

1. Hypoglycemia in the Mother

Rarely, antenatal corticosteroids may increase the risks of developing hypoglycemia in women. The baby of a hypoglycemic mother may experience developmental delays later in life.

2. Long-Term Health Issues For The Baby

Evidence shows that antenatal corticosteroids are absolutely safer even for women with preeclampsia and gestational diabetes. But, in some cases, the repeated courses of antenatal corticosteroids may affect the fetal Hypothalamic-Pituitary-Adrenal axis. This may result in the baby experiencing long-term health issues (cardiometabolic) like heart problems, insulin resistance, diabetes, fatty liver, and adverse neurological disorders that affect learning abilities and mental health in children.

Antenatal corticosteroids for expecting mothers significantly reduce the percentage of preterm neonates born with the risk of RDS and other health complications. Administration of steroids for an anticipated preterm birth also reduces the risk of neonatal morbidities and mortality due to complications.

A controlled dosage of antenatal corticosteroids does not lead to any long-term health risks in babies and mothers. You can discuss this with your doctor to gain a knowledge of all the potential benefits and risks of antenatal corticosteroids. This will help the expecting mothers and the family stay in tranquillity.

[Read : Hypoglycemia In Pregnancy]

FAQ’s

1. Which Steroid is Best For Antenatal Lung Maturity?

Antenatal corticosteroids are synthetic hormones that are administered to expecting mothers with anticipated preterm delivery. It will speed up and enhance the lung maturity in the fetus, thus reducing the risks of being on prolonged ventilation and oxygen support.

2. Can Antenatal Corticosteroids Harm Fetuses?

A controlled dosage can rescue the fetus from being born with the risk of neonatal morbidities and mortalities. However, repeated courses of antenatal corticosteroid exposure can pose long-term health issues like neurological and cardiometabolic disorders in children. These are not temporary but can stick along.

3. Does Antenatal Corticosteroid Affect Fetal Heart Rate?

Administering antenatal corticosteroids reduce the risks of preterm neonates having lung diseases. However, studies show that there is a transient (short-term) effect on Fetal Heart Rate (FHR) observed in younger and older fetuses with the consumption of antenatal corticosteroids (betamethasone).

Read Also: What is Premature Delivery by Dr Lathiesh Kumar Kambham