Corticosteroids in Preterm Labor and Premature Infants

Nurse and premature baby

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The womb is the best place to grow your baby. However, about 10% of pregnant women in the United States will experience premature labor, which is defined as going into labor before 37 weeks gestation. Many of these women will give birth to premature infants. Corticosteroid is a medication often given to pregnant people who go into labor early in order to speed up the maturation of the baby's lungs before delivery.

Maturing the lungs is an important part of improving the baby's health outcomes. The more premature your baby is, the more likely they are to experience complications and potential long-term effects. In fact, preterm babies are at significantly increased risk of complications with nearly every organ system when compared with full-term infants.

How Long Is the Average Pregnancy?

The average pregnancy lasts about 40 weeks. The definition of a term pregnancy is a pregnancy between 37 and 42 weeks gestation. However, due to advances in medical science, infants born as early as 22 weeks can survive with appropriate medical care and hospitalization, although often with significant disabilities.

It's important to note that the longer a baby stays in the uterus, the better its chances are of surviving and having fewer complications after birth. Very preterm babies, which are defined as birth before 32 weeks gestation, carry much higher rates of mortality and morbidity.

Slightly Premature Infants Are Also at Risk

While in the past there was a general acceptance that infants born just slightly premature are not in as much danger as those born a few weeks earlier, new information says this is simply not true. 

Even late preterm infants, which are defined as those born between 34 and 37 weeks and compromise around 75% of all preemies, have an increased risk of many complications after birth. These late preterm infants also suffer higher infant mortality rates than babies born at full term.

Steroid Injection for Fetal Lung Development

Using injections of corticosteroids to improve the outlook for premature infants is one of the best advances in fetal medicine. This treatment has been routinely used since its introduction in 1972. Since then, the  American College of Obstetricians and Gynecologists, National Institutes of Health, and other professional organizations have encouraged their use in pregnant moms who are at risk for preterm labor or birth.

Betamethasone and dexamethasone are the two most commonly used steroids for fetal lung development. The use of these steroids provides immense benefits because they reduce the risk of respiratory distress syndrome (RDS), intracranial hemorrhaging, and other serious complications of the lungs.​

Timing and Number of Doses

Some doctors advocate for giving multiple doses of steroids to pregnant people at risk of preterm labor to protect their baby's lungs, often giving shots 24 hours apart. However, often one dose is given due to the potential adverse effects of administering multiple or higher doses of the medication for both the mother and baby. Research is ongoing on this topic, but what is clear is that a single dose often dramatically improves the outlook for premature babies.

Ideally, shots are administered at least 24 hours before the baby is born to give the medication enough time to work. Optimal corticosteroid dosage and timing of the injection depends on your specific circumstances and the medical history of the mother, as well as the practices of the doctor and hospital.

Much evidence supports having a single lower dose administered for preterm deliveries before 37 weeks gestation to both accelerate fetal lung development and limit maternal side effects.

If you are in preterm labor or at risk of preterm labor, your doctor will likely discuss your options with you, including the possible benefits and risks of getting a corticosteroid injection to provide extra support for your baby's lungs.

A Word From Verywell

Going into labor early brings with it significant risks to your baby—and stress as a parent. Know that your medical providers will do everything they can to protect your health and the health of your baby. An effective tool they have at their disposal is giving you a corticosteroid injection. This medication can help mitigate some of the risks of preterm birth and greatly improve the chance that your baby will have fewer complications.

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