Measurement of betamethasone concentration in maternal serum treated for fetal lung maturity; Is it feasible?

Association between betamethasone levels and respiratory distress syndrome in preterm births: A prospective cohort study

The recommended fixed dosage of betamethasone for pregnancies at risk of preterm birth was determined in the 1970s, regardless of gestational age (GA), number of fetuses, and maternal weight. We aimed to examine the association between maternal and neonatal betamethasone serum levels and neonatal respiratory distress syndrome (RDS) and to examine whether levels correlate with maternal weight, GA, or number of fetuses. A prospective study was conducted at a single academic medical center between August 2016 and February 2019. Women received betamethasone and delivered between 28⁺⁰ and 34⁺⁶ weeks were included. Maternal serum levels (MSLs), and neonatal serum levels (NSLs) of betamethasone at delivery were analyzed using Corticosteroid enzyme-linked immunosorbent assay kit. RDS was diagnosed according to clinical and radiographic findings. We assumed that the sensitivity of NSLs to detect RDS is 95%; hence, 150 neonates were needed (power 80%, alpha 0.05). Overall, 124 women were included; including 96 (77.4%) singletons, 26 (21.0%) twins, and 2 (1.6%) triplets, corresponding to 154 neonates. RDS was diagnosed in 35 neonates (22.7%). After adjusting for GA, time elapsed from the last dose, and number of doses, NSLs were associated with RDS (relative risk: 0.97, 95% confidence interval: 0.94-0.99, p = 0.011). A level of 6.00 ng/ml predicted RDS with a sensitivity of 80.0% and specificity of 64.7%. Adjusted MSLs were not associated with RDS. Both maternal and neonatal serum levels were not associated with the number of fetuses and maternal weight. In conclusion, NSLs are associated with RDS whereas MSLs are not.

Effects of betamethasone on fetoplacental and maternal hemodynamics in preterm pregnancies

OBJECTIVE

To evaluate the possible effects of prenatal steroid administration on Doppler parameters of the umbilical artery, uterine artery, middle cerebral artery, and ductus venosus, the cerebroplacental ratio, and the amniotic fluid index in preterm fetuses.

METHODS

The present prospective observational study was performed at the Perinatology Department of Trakya University, Edirne, Turkey, between June 1, 2015, and September 1, 2016. It included patients with healthy singleton pregnancies who had received betamethasone at 24-34 weeks of pregnancy. Doppler parameters were measured before (0 hours) and 24, 48, and 72 hours after the administration of betamethasone (two intramuscular doses of 12 mg each, administered 24 hours apart).

RESULTS

There were 68 patients included. Pairwise comparisons demonstrated that, at 72 hours after betamethasone administration, the umbilical artery resistance index (P=0.038), the middle cerebral artery systolic/diastolic velocity ratio (P=0.007), and the amniotic fluid index (P=0.017) were reduced, whereas the end-diastolic velocity of the middle cerebral artery was increased (P=0.012), compared with baseline values.

CONCLUSION

Betamethasone had favorable effects on fetal cerebral circulation, with increased end-diastolic velocity in the middle cerebral artery; this could represent a positive effect on cerebral blood circulation and decreased flow resistance in the umbilical artery.