Dexamethasone Use at 33 Weeks Gestation for Fetal Lung Maturation

Recommended Dosing Regimen

The American College of Obstetricians and Gynecologists recommends administering betamethasone 12 mg intramuscularly in two doses, 24 hours apart, for singleton pregnancies at 33 weeks who are at high risk of delivery within the next 7 days and before 37 weeks 1, 3
The standard recommendation for antenatal corticosteroids extends from 24 0/7 weeks through 36 6/7 weeks of gestation, with a dosing regimen of betamethasone 12 mg intramuscularly in two doses, 24 hours apart, or dexamethasone 12 mg intramuscularly in two doses, 24 hours apart if betamethasone is unavailable 1, 4

Antenatal corticosteroids at 33 weeks significantly reduce the need for respiratory support, with a relative risk of 0.80, in patients at high risk of preterm delivery 1, 3
Antenatal corticosteroids at 33 weeks also decrease severe respiratory morbidity, with a relative risk of 0.67, in patients at high risk of preterm delivery 1, 3

The American College of Obstetricians and Gynecologists recommends administering corticosteroids if the patient has preterm labor with intact membranes and cervical dilation ≥3 cm or ≥75% cervical effacement, with a high risk of delivery within 7 days 1, 3
Corticosteroids should also be administered if the patient has spontaneous rupture of membranes or expected preterm delivery for medical indications, such as gestational hypertension or preeclampsia, with planned delivery between 24 hours and 7 days 1, 3

The American College of Obstetricians and Gynecologists recommends not administering corticosteroids if the patient has pregestational diabetes mellitus, as this significantly increases the risk of severe neonatal hypoglycemia 1, 5, 3
Corticosteroids should not be administered if there is a low likelihood of delivery before 37 weeks of gestation or if the patient has already received a prior course of antenatal corticosteroids in the late preterm period 1, 3

The optimal benefit window for antenatal corticosteroids is when delivery occurs within 7 days of administration, with a significant reduction in neonatal respiratory morbidity and mortality 1, 2
Patients must be thoroughly counseled that long-term neurodevelopmental risks of antenatal corticosteroids remain uncertain, with established short-term benefits and uncertain long-term effects 1, 6, 3

The American College of Obstetricians and Gynecologists recommends considering administration of antenatal corticosteroids in select populations not included in original trials, such as multiple gestations reduced to singleton on or after 14 0/7 weeks of gestation, pregnancies with fetal anomalies, and patients expected to deliver in <12 hours 1, 3

For pregnant patients with liver diseases, such as HELLP syndrome or acute fatty liver of pregnancy, high-dose dexamethasone or betamethasone should be given as per national guidance to improve fetal lung maturity if delivery is planned before 35 weeks' gestation 8
Corticosteroid treatment should not be given to improve maternal outcomes in HELLP syndrome, but only for fetal lung maturation, with consideration of administration when delivery is imminent (<34 weeks) 8, 9