Janas Przemysław, Radoń-Pokracka Małgorzata, Nowak Magdalena, Staroń Agata, Wilczyńska Gabriela, Brzozowska Mirella, Huras Hubert
Department of Obstetrics and Perinatology, Jagiellonian University Medical College, Cracow, Poland.
Department of Obstetrics and Perinatology, Jagiellonian University Medical College, Cracow, Poland.
Taiwan J Obstet Gynecol. 2019 Mar;58(2):278-281. doi: 10.1016/j.tjog.2019.01.020.
Ultrasound estimation of foetal weight is a very important aspect of antenatal care. The role of amniotic fluid volume as a potential factor which may impede the relevance of ultrasonographic foetal weight estimation is still questionable. The aim of our study was to evaluate the impact of isolated oligohydramnios on the accuracy of ultrasound foetal weight estimation in at term pregnancies when examination was performed within 48 h before delivery.
The retrospective cohort study included 1831 women with low-risk, singleton, at term pregnancy. Estimated foetal weight (EFW) was calculated using Hadlock-4 formula. Exclusion criteria consisted of multiple pregnancies, active phase of labour, preeclampsia, foetal growth restriction, foetal anomalies, gestational diabetes mellitus and the evidence of intrauterine infection. Isolated oligohydramnios was defined as Amniotic Fluid Index (AFI) ≤50 mm without any other foetal anomalies. EFW and actual birth weight (ABW) were compared by calculation of: absolute error (AE), absolute percentage error (APE) and substantial error (SE) = APE >10%.
Participants were divided into 2 groups: Group 1: patients with normal AFI (50 ≤ AFI ≤250 mm; n = 1602) and Group 2: (isolated oligohydramnios, n = 229). There were not observed statistically significant differences between mean ABW and mean EFW in both groups (Group 1: p = 0.525; Group 2: p = 0.317). Mean AE in Group 1 was 221.8 g and 223.1 g in Group 2 (p = 0.919). Mean APE was 6.54% and 6.64% in Group 1 and 2 respectively (p = 0.816). SE ratio was 21.9% in Group 1 and 19.2% in Group 2. Underestimation to overestimation ratio in Group 1 was 1.01 and 0.84 in Group 2.
Amniotic fluid volume has limited impact on ultrasound foetal weight estimation. In oligohydramnios group there might be a tendency of overestimation of neonatal ABW.
超声估计胎儿体重是产前护理的一个非常重要的方面。羊水过少作为可能影响超声胎儿体重估计相关性的潜在因素，其作用仍存在疑问。我们研究的目的是评估在足月妊娠且在分娩前48小时内进行检查时，单纯羊水过少对超声估计胎儿体重准确性的影响。
这项回顾性队列研究纳入了1831例低风险、单胎、足月妊娠的女性。使用Hadlock-4公式计算估计胎儿体重（EFW）。排除标准包括多胎妊娠、产程活跃期、子痫前期、胎儿生长受限、胎儿畸形、妊娠期糖尿病以及宫内感染的证据。单纯羊水过少定义为羊水指数（AFI）≤50mm且无任何其他胎儿异常。通过计算绝对误差（AE）、绝对百分比误差（APE）和显著误差（SE）=APE>10%来比较EFW和实际出生体重（ABW）。
参与者分为两组：第1组：AFI正常的患者（50≤AFI≤250mm；n = 1602）和第2组：（单纯羊水过少，n = 229）。两组的平均ABW和平均EFW之间未观察到统计学上的显著差异（第1组：p = 0.525；第2组：p = 0.317）。第1组的平均AE为221.8g，第2组为223.1g（p = 0.919）。第1组和第2组的平均APE分别为6.54%和6.64%（p = 0.816）。第1组的SE比率为21.9%，第2组为19.2%。第1组的低估与高估比率为1.01，第2组为0.84。
羊水量对超声估计胎儿体重的影响有限。在羊水过少组中，可能存在高估新生儿ABW的趋势。
