Egerman R S, Walker R A, Mercer B M, Doss J L, Sibai B M, Andersen R A
Department of Obstetrics and Gynecology, University of Tennessee, Memphis, TN, USA.
Am J Obstet Gynecol. 1998 Nov;179(5):1234-6. doi: 10.1016/s0002-9378(98)70138-3.
Unconjugated estriol production depends on fetal adrenal androgen precursors. Fetal exposure to exogenous glucocorticoids results in adrenal suppression with a subsequent decrease in maternal serum unconjugated estriol levels. We compared the efficacy between oral and intramuscular dexamethasone in maternal serum unconjugated estriol suppression at 48 hours after the initial dose among women at risk for preterm delivery.
Twenty-four gravidas at risk for preterm delivery were randomized to receive either 6 mg intramuscular or 8 mg oral dexamethasone every 12 hours for a total of 4 doses. Blood samples (9 mL) were obtained before the initial dexamethasone administration and again after the fourth dose. Serum was separated and frozen at -70 degreesC and subsequently underwent batch analysis. Unconjugated estriol levels were determined by radioimmunoassay with intra-assay and interassay coefficients of variation of 7.9% and 5.5%, respectively. All values are reported as mean +/- SD. The primary statistical analysis was a t test, with P <.05 considered significant.
At the time of dexamethasone administration, gestational ages in both groups were similar. Predexamethasone and postdexamethasone unconjugated estriol levels were also similar between the intramuscular and oral groups (5.39 +/- 3.99 vs 1.80 +/- 2.49 ng/mL and 6.05 +/- 3.00 vs 1.61 +/- 1.03 ng/mL, respectively, P >.05). No difference in percent decrease in unconjugated estriol levels was found between the intramuscular (0.67 +/- 0.24) and oral (0.65 +/- 0.39) groups.
Oral dexamethasone (8 mg) produces similar maternal serum unconjugated estriol suppression compared with intramuscular dexamethasone (6 mg) when evaluated 48 hours after administration.
未结合雌三醇的产生依赖于胎儿肾上腺雄激素前体。胎儿暴露于外源性糖皮质激素会导致肾上腺抑制，进而使母体血清未结合雌三醇水平降低。我们比较了在初剂量后48小时，口服和肌肉注射地塞米松对有早产风险的孕妇血清未结合雌三醇的抑制效果。
24名有早产风险的孕妇被随机分为两组，一组每12小时肌肉注射6毫克地塞米松，另一组每12小时口服8毫克地塞米松，各给药4次。在首次给予地塞米松之前和第4次给药后采集血样（9毫升）。分离血清并在-70℃冷冻，随后进行批量分析。采用放射免疫分析法测定未结合雌三醇水平，批内变异系数和批间变异系数分别为7.9%和5.5%。所有数值均以平均值±标准差表示。主要统计分析采用t检验，P<0.05为有统计学意义。
在地塞米松给药时，两组的孕周相似。肌肉注射组和口服组给药前和给药后的未结合雌三醇水平也相似（分别为5.39±3.99对1.80±2.49纳克/毫升和6.05±3.00对1.61±1.03纳克/毫升，P>0.05）。肌肉注射组（0.67±0.24）和口服组（0.65±0.39）未结合雌三醇水平的下降百分比无差异。
给药48小时后评估，口服地塞米松（8毫克）与肌肉注射地塞米松（6毫克）对母体血清未结合雌三醇的抑制效果相似。
