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

Abstract

BackgroundThe association between maternal serum concentration of betamethasone given for fetal lung maturity and perinatal outcome has not been investigated. This may be due to an absence of a reliable method for measuring serum betamethasone concentrations. We aimed in the current study to assess the feasibility of a specific ELISA kit to measure the concentrations of betamethasone in maternal serum and to examine the trend of sequential measurements after a course of betamethasone for fetal lung maturity.MethodsPregnant women at risk for preterm birth who received betamethasone between 24 and 34 weeks of gestation were prospectively included. Serum concentrations were determined before administering betamethasone (baseline), and 36 hours, 48 hours, 72 hours, and 5 to 7 days after the 1st dose. Betamethasone concentration in samples was determined using Corticosteroid ELISA kit. The Friedman test was used to test whether there were significant differences between the measurements.ResultsFive singleton pregnancies were included. Using the ELISA kit, betamethasone concentration in maternal serum samples was obtained for all women. Among the five measurements performed, the concentration was highest at 36 hours after the 1st dose and close to baseline at the 5th measurement performed after 5 to 7 days (p < 0.05). Serum concentration varied at each time point between the five women but similar trend was observed.ConclusionBetamethasone concentration is measurable in the serum of pregnant women with this ELISA kit.

Effects of betamethasone on fetoplacental and maternal hemodynamics in preterm pregnancies

“…In the present study, all patients received only a loading dose of nifedipine within 1 hour without a maintenance dose owing to the cessation of uterine contractions. Moreover, the peak plasma concentration of nifedipine is reached after 1 hour and its half‐life is approximately 3 hours, whereas the highest serum concentration of betamethasone is seen 36 hours after the first dose and betamethasone continues to be effective for to 5–7 days in pregnant women . In addition, all women in the present study received the second betamethasone dose 24 hours after the first dose.…”

“…Moreover, the peak plasma concentration of nifedipine is reached after 1 hour and its half-life is approximately 3 hours, 20 whereas the highest serum concentration of betamethasone is seen 36 hours after the first dose and betamethasone continues to be effective for to 5-7 days in pregnant women. 25 In addition, all women in the present study received the second betamethasone dose 24 hours after the first dose. Therefore, it is suggested that the Doppler parameters in the present study were affected by betamethasone only because patients received only a loading dose of nifedipine and because of the short half-life of nifedipine versus the long duration of betamethasone action.…”

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

“…Nevertheless, according to a previous publication, the concentration diminished gradually to a level close to the baseline at 5–7 days after the first course of betamethasone. 5 Besides, most women who had a rescue dose did not receive it back‐to‐back. Finally, we made a subanalysis restricted to women who received one course only.…”

“…In the present study, both maternal and neonatal (cord) levels were analyzed using the same Corticosteroid enzyme‐linked immunosorbent assay (ELISA) kit (Randox Laboratories Ltd.). Preliminary results showed that the kit is valid for determining betamethasone concertation 5 . The assay exhibits very low cross‐reactivity for cortisol (<0.5%), which is vital in minimizing interference from endogenous cortisol.…”

“…Preliminary results showed that the kit is valid for determining betamethasone concertation. 5 The assay exhibits very low cross‐reactivity for cortisol (<0.5%), which is vital in minimizing interference from endogenous cortisol. In the current study, 3 ml of maternal blood was drawn at delivery of the neonates, and was sent together with blood drawn from the umbilical cord immediately after birth.…”