Supplementary Material for: Short-Term Effects of Dexamethasone versus Betamethasone on Ultrasonic Measures of Fetal Well-Being: Cohort from a Blinded, Randomized Trial

Introduction: Maternal corticosteroid administration for anticipated preterm birth is common; however, the corticosteroid effect on fetal ultrasound and cardiotocograph (CTG) remains contested. This study aimed to evaluate short-term ultrasound and CTG impact of (a) dexamethasone versus betamethasone (b) pooled corticosteroid effect. Methods: Substudy of blinded randomized trial of dexamethasone versus betamethasone (given <34 weeks). Umbilical artery (UA), middle cerebral artery (MCA), ductus venosus (DV), and uterine artery Doppler, myocardial performance index (MPI), biophysical profile (BPP), and CTG measured pre-corticosteroid then 1, 2, 4, and 7 days post-corticosteroid. Results: Of 47 fetuses (39 singleton; 4 dichorionic, diamniotic twins; and 4 monochorionic, diamniotic twins) in the February 2012–2013 period, 24 received dexamethasone and 23 betamethasone at average gestation 29.8 ± 2.9 weeks. Thirteen pregnancies (30%) had pre-corticosteroid fetal concerns (estimated weight <10th centile and/or abnormal UA/MCA Doppler). Few significant differences were seen post-corticosteroid: DV pulsatility index and right MPI initially decreased 15–20%, and average BPP decreased slightly on days 1–2. There were no major differential effects of dexamethasone versus betamethasone. Discussion/Conclusion: No substantive post-corticosteroid effects were seen for most ultrasound/CTG measures in fetuses with heightened preterm birth risk but predominantly normal pre-corticosteroid measures. Clinically, this suggests avoiding overreliance on individual measures for delivery decisions post-corticosteroid; equally, multiple/marked ultrasound changes suggest true pathology and not corticosteroid effect.

引言：针对预计早产的产妇给予糖皮质激素（corticosteroid）治疗是临床常见操作，但糖皮质激素对胎儿超声检查及胎心宫缩图（cardiotocograph, CTG）的影响仍存在争议。本研究旨在评估两类干预的短期超声及CTG影响：(a) 地塞米松与倍他米松的对比效果；(b) 糖皮质激素的整体效应。
研究方法：本研究为一项针对地塞米松与倍他米松（给药孕周<34周）的盲法随机对照试验的亚组分析。分别在糖皮质激素给药前，以及给药后1、2、4、7天，对胎儿进行脐动脉（umbilical artery, UA）、大脑中动脉（middle cerebral artery, MCA）、静脉导管（ductus venosus, DV）、子宫动脉多普勒血流检测，同时评估心肌性能指数（myocardial performance index, MPI）、生物物理评分（biophysical profile, BPP）及CTG。
研究结果：本研究纳入2012年2月至2013年间的47例胎儿（39例单胎、4例双绒毛膜双羊膜囊双胎、4例单绒毛膜双羊膜囊双胎），平均妊娠孕周为29.8±2.9周，其中24例接受地塞米松治疗，23例接受倍他米松治疗。13例妊娠（占比30%）在糖皮质激素给药前存在胎儿异常征象：估计胎儿体重低于第10百分位数，和/或UA/MCA多普勒血流检测结果异常。给药后仅观察到少量显著差异：静脉导管搏动指数及右侧心肌性能指数初始下降15%~20%，平均生物物理评分在给药后第1~2天略有降低。地塞米松与倍他米松之间未观察到显著的疗效差异。
讨论与结论：对于早产风险升高但给药前超声及CTG指标大多正常的胎儿，绝大多数检测指标在糖皮质激素给药后未出现实质性变化。临床实践中，这提示我们应避免在糖皮质激素给药后仅依靠单一指标做出分娩决策；同理，若出现多项或显著的超声指标异常，则提示存在真正的病理改变，而非糖皮质激素的药物影响。