Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sidney Kimmel Medical College, Thomas Jefferson University Hospital, Philadelphia, PA.
Department of Obstetrics, Gynecology, and Reproductive Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX.
Am J Obstet Gynecol MFM. 2020 Nov;2(4):100242. doi: 10.1016/j.ajogmf.2020.100242. Epub 2020 Oct 3.
This study aimed to determine whether routine third-trimester ultrasounds in low-risk pregnancies decrease the rate of perinatal death compared with regular antenatal care with serial fundal height measurements.
This was a systematic review and meta-analysis of randomized control trials to identify relevant studies published from inception to October 2019. The databases used were Ovid, PubMed, Scopus, ClinicalTrials.gov, and the Cochrane Central Register of Controlled Trials using a combination of key words related to "third trimester ultrasound" and "low-risk."
We included all randomized control trials of singleton, nonanomalous low-risk pregnancies that were randomized to either one or more third-trimester ultrasounds (ultrasound group) or serial fundal height (fundal height group). Exclusion criteria were patients with multiple gestations, maternal medical complications, or fetal abnormalities requiring a third-trimester ultrasound.
The primary outcome was the rate of perinatal death. The secondary outcomes were rates of fetal growth restriction, suspected large for gestational age, polyhydramnios, oligohydramnios, fetal anomalies, antenatal interventions, stillbirth, neonatal death, cesarean delivery, induction of labor, and other neonatal outcomes. This meta-analysis was performed with the use of the random effects model of DerSimonian and Laird to produce relative risk or mean difference with a corresponding 95% confidence interval.
A total of 7 randomized control trials with 23,643 participants (12,343 in the ultrasound group vs 11,300 in the fundal height group) were included. The total rate of perinatal death was similar among the groups (41 of 11,322 [0.4%] vs 34 of 10,285 [0.3%]; relative risk, 1.14; 95% confidence interval, 0.68-1.89). The rate of fetal growth restriction was higher in the ultrasound group (763 of 10,388 [7%] vs 337 of 9021 [4%]; relative risk, 2.11; 95% confidence interval, 1.86-2.39) and the rate of suspected large for gestational age (1060 of 3513 [30%] vs 375 of 3558 [11%]; relative risk, 2.84; 95% confidence interval, 2.6-3.2). Polyhydramnios was also significantly higher in the ultrasound group than the fundal height group (18 of 323 [6%] vs 4 of 322 [1%] relative risk, 3.93; 95% confidence interval, 1.4-11). The rates of the remainder of the secondary outcomes were similar among the groups.
Routine third-trimester ultrasounds do not decrease the rate of perinatal death compared with serial fundal height in low-risk pregnancies. Ideally, an adequately powered trial is warranted to determine whether perinatal mortality in the fundal height group can be reduced by one-third with third-trimester ultrasound.
本研究旨在确定与定期产前检查和宫底高度测量相比，低危妊娠中的常规孕晚期超声检查是否会降低围产期死亡率。
这是一项系统评价和荟萃分析，对从开始到 2019 年 10 月发表的随机对照试验进行了检索。使用的数据库包括 Ovid、PubMed、Scopus、ClinicalTrials.gov 和 Cochrane 对照试验中心注册数据库，使用了与“孕晚期超声”和“低危”相关的关键词的组合。
我们纳入了所有单胎、非畸形低危妊娠的随机对照试验，这些试验被随机分为一次或多次孕晚期超声（超声组）或多次宫底高度（宫底高度组）。排除标准为多胎妊娠、母体合并症或需要进行孕晚期超声检查的胎儿异常。
主要结局为围产儿死亡率。次要结局为胎儿生长受限、疑似巨大儿、羊水过多、羊水过少、胎儿异常、产前干预、死产、新生儿死亡、剖宫产、引产和其他新生儿结局。本荟萃分析采用 DerSimonian 和 Laird 的随机效应模型，得出相对风险或均数差值及其相应的 95%置信区间。
共有 7 项随机对照试验纳入了 23643 名参与者（超声组 12343 名，宫底高度组 11300 名）。两组围产儿死亡率相似（超声组 41 例/11322 例[0.4%]，宫底高度组 34 例/10285 例[0.3%]；相对风险，1.14；95%置信区间，0.68-1.89）。超声组胎儿生长受限发生率较高（超声组 763 例/10388 例[7%]，宫底高度组 337 例/9021 例[4%]；相对风险，2.11；95%置信区间，1.86-2.39），疑似巨大儿发生率也较高（超声组 30%，1060 例/3513 例，宫底高度组 11%，375 例/3558 例；相对风险，2.84；95%置信区间，2.6-3.2）。超声组羊水过多的发生率也明显高于宫底高度组（超声组 18 例/323 例[6%]，宫底高度组 4 例/322 例[1%]；相对风险，3.93；95%置信区间，1.4-11）。其余次要结局的发生率在两组间相似。
与定期宫底高度测量相比，低危妊娠中常规孕晚期超声检查并不能降低围产儿死亡率。理想情况下，需要进行一项充分有力的试验，以确定在宫底高度组中，是否可以通过孕晚期超声检查将围产儿死亡率降低三分之一。
