Steroid therapy in pregnancy - how does it work and why is it used?
As we mentioned at the beginning, steroid therapy is used in pregnant women with indications for this purpose, to accelerate fetal lung development. The beginning of their development is around the fourth month of pregnancy - that's when the alveoli begin to appear and begins surfactant production (a substance that prevents them from collapsing and sticking). Lung development process lasts about 12 weeks and ends only around 35-36 weeks of pregnancy, therefore, newborns born before 36 tc. they are not fully prepared to breathe. Fortunately, thanks to the use of antenatal steroids, the lungs are stimulated to grow faster, and premature babies are more likely to survive.
What is important, corticosteroids significantly reduce the risk of neonatal death within the first 24 hours of administration, and the greatest effectiveness in the prevention of respiratory distress syndrome (RDS) is between 24 hours and 7 days after the second dose. The use of antenatal steroids has been proven to significantly reduce not only perinatal mortality and morbidity of newborns on RDS, but also reduce the risk of intraventricular bleeding and the development of necrotic enteritis (NEC).
When there is a need for steroid therapy during pregnancy
The main indication for the use of steroid therapy in pregnant women is risk of spontaneous or induced preterm delivery (i.e. taking place before the end of 37 weeks of pregnancy), which can lead to, among others excessive uterine contractions, cervical insufficiency, gestational hypertension, intrauterine infection (leading to rupture of the membranes) or polyhydramnios. It is carried out in women between 24 and 34 weeks of pregnancy, both in single and multiple pregnancies.
In order to reduce the risk of perinatal complications, in particular respiratory distress syndrome, corticosteroids should also be used in all pregnancies that will be resolved before the end of week 38.
In addition to numerous indications for steroid therapy, there are also to it contraindications, among which is a generalized infection in a pregnant woman (including tuberculosis or sepsis). If there is inflammation of the membranes and placenta, there is no contraindication to its use, however, it cannot be a reason for delaying delivery if it is necessary to carry it out earlier due to the state of the mother or the fetus.
What does a steroid therapy cycle look like in pregnancy?
Steroid therapy is used in the case of the above-mentioned indications and is carried out in the form of a single cycle. Steroid preparations are given to future mothers between 24 and 34 weeks of pregnancy in strictly defined schedules.
In Poland, there are two schemes of antenatal steroids lasting 48 hours (the patient uses only one of the following variants):
- with the use of dexamethasone - the preparation is administered intramuscularly, four times at a dose of 6 mg every 12 hours
- using betamethasone - the preparation is administered intramuscularly, twice in a dose of 12 mg every 24 hours.
Occasionally, pregnant women who received a cycle of steroid therapy before 26 weeks of pregnancy may be considered to repeat it.
According to various studies carried out, a single cycle of antenatal steroids used in connection with the risk of premature delivery is not associated with direct adverse effects on mother and fetus (in this case, there will also be no complications of long-term steroid therapy such as carbohydrate metabolism disorders, osteoporosis, stretch marks or weakening of immunity) .
In summary, the use of pregnant antenatal steroids is designed to accelerate the development of the lungs of the fetus, to give it a better chance of survival in the event of a threat of preterm delivery, when the baby is not yet fully ready for mother's life. Due to the proven lack of its adverse effects for both mother and child, steroid therapy should not be feared, as its use reduces the risk of not only perinatal death, but also the development of respiratory distress syndrome, necrotizing enterocolitis and intracranial bleeding.