East Christine E, Leader Leo R, Sheehan Penelope, Henshall Naomi E, Colditz Paul B, Lau Rosalind
School of Nursing and Midwifery/Maternity Services, Monash University/Monash Health, 246 Clayton Road, Clayton, Victoria, Australia, 3168.
Cochrane Database Syst Rev. 2015 May 1;2015(5):CD006174. doi: 10.1002/14651858.CD006174.pub3.
Fetal scalp blood sampling for lactate estimation may be considered following identification of an abnormal or non-reassuring fetal heart rate pattern. The smaller volume of blood required for this test, compared with the more traditional pH estimation, may improve sampling rates. The appropriate use of this practice mandates systematic review of its safety and clinical effectiveness prior to widespread introduction.
To evaluate the effectiveness and risks of fetal scalp lactate sampling in the assessment of fetal well-being during labour, compared with no testing or alternative testing.
We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2015).
All published and unpublished randomised and quasi-randomised trials that compared fetal scalp lactate testing with no testing or alternative testing to evaluate fetal status in the presence of a non-reassuring cardiotocograph during labour.
We used the standard methodological procedures of the Cochrane Pregnancy and Childbirth Group. Two review authors independently assessed the studies.
The search identified two completed randomised controlled trials (RCTs) and two ongoing trials. The two published RCTs considered outcomes for 3348 mother-baby pairs allocated to either lactate or pH estimation of fetal blood samples when clinically indicated in labour. Overall, the published RCTs were of low or unclear risk of bias. There was a high risk of performance bias, because it would not have been feasible to blind clinicians or participants.No statistically significant between-group differences were found for neonatal encephalopathy (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.32 to 3.09, one study, 2992 infants) or death. No studies reported neonatal seizures. We had planned to report death with other morbidities, for example, neonatal encephalopathy; however, the data were not available in a format suitable for this, therefore death due to congenital abnormality was considered alone. The three reported neonatal deaths occurred in babies with diaphragmatic hernias (n = 2) or congenital cardiac fibrosis (n = 1). All three babies had been randomised to the pH group and were not acidaemic at birth.There were no statistically significant differences for any of the pre-specified secondary fetal/neonatal/infant outcomes for which data were available. This included low Apgar score at five minutes (RR 1.13, 95% CI 0.76 to 1.68, two studies, 3319 infants) and admission to neonatal intensive care units (RR 1.02, 95% CI 0.83 to 1.25, one study, 2992 infants), or metabolic acidaemia (RR 0.91, 95% CI 0.60 to 1.36, one study, 2675 infants) considered within the studies, either overall or where data were available for those where fetal blood sampling had occurred within 60 minutes of delivery.Similar proportions of fetuses underwent additional tests to further evaluate well-being during labour, including scalp pH if in the lactate group or scalp lactate if in the pH group (RR 0.22, 95% CI 0.04 to 1.30, two studies, 3333 infants;Tau² 1.00, I² = 58%). Fetal blood sampling attempts for lactate and pH estimation were successful in 98.7% and 79.4% of procedures respectively in the one study that reported this outcome.There were no significant between-group differences in mode of birth or operative birth for non-reassuring fetal status, either for all women, or within the group where the fetal blood sample had been taken within 60 minutes of delivery (for example, caesarean section for all enrolled, RR 1.09, 95% CI 0.97 to 1.22, two studies, 3319 women; operative delivery for non-reassuring fetal status for all enrolled RR 1.02, 95% CI 0.93 to 1.11, one study, 2992 women).Neither study reported on adverse effects of fetal scalp lacerations or maternal anxiety.
AUTHORS' CONCLUSIONS: When further testing to assess fetal well-being in labour is indicated, fetal scalp blood lactate estimation is more likely to be successfully undertaken than pH estimation. Further studies may consider subgroup analysis by gestational age, the stage of labour and sampling within a prolonged second stage of labour. Additionally, we await the findings from the ongoing studies that compare allocation to no fetal blood sample with sampling for lactate and address longer-term neonatal outcomes, maternal satisfaction with intrapartum fetal monitoring and an economic analysis.
在识别出异常或令人不安的胎儿心率模式后，可考虑进行胎儿头皮采血以测定乳酸水平。与更为传统的pH值测定相比，该检测所需的血量较少，这可能会提高采样率。在广泛应用这一做法之前，需要对其安全性和临床有效性进行系统评价。
与不进行检测或采用其他检测方法相比，评估分娩期间胎儿头皮采血测定乳酸水平在评估胎儿健康状况方面的有效性和风险。
我们检索了Cochrane妊娠与分娩组试验注册库（2015年1月31日）。
所有已发表和未发表的随机及半随机试验，这些试验将胎儿头皮采血测定乳酸水平与不进行检测或采用其他检测方法进行比较，以评估分娩期间出现令人不安的胎心监护图形时的胎儿状况。
我们采用了Cochrane妊娠与分娩组的标准方法程序。两位综述作者独立评估了这些研究。
检索到两项已完成的随机对照试验（RCT）和两项正在进行的试验。两项已发表的RCT纳入了3348对母婴，当临床上提示分娩时，将其随机分配至乳酸水平或pH值测定胎儿血样组。总体而言，已发表的RCT存在低或不明确的偏倚风险。存在较高的实施偏倚风险，因为对临床医生或参与者进行盲法操作不可行。在新生儿脑病（风险比（RR）1.00，95%置信区间（CI）0.32至3.09，一项研究，2992例婴儿）或死亡方面，未发现组间有统计学显著差异。没有研究报告新生儿惊厥情况。我们原计划报告死亡与其他疾病（如新生儿脑病）的情况；然而，数据格式不适合，因此仅考虑先天性异常导致的死亡。报告的三例新生儿死亡发生在患有膈疝（n = 2）或先天性心脏纤维化（n = 1）的婴儿中。所有三例婴儿均被随机分配至pH值组，出生时无酸中毒。对于任何可获得数据的预先设定的次要胎儿/新生儿/婴儿结局，均未发现统计学显著差异。这包括5分钟时阿氏评分低（RR 1.13，95%CI 0.76至1.68，两项研究，3319例婴儿）、入住新生儿重症监护病房（RR 1.02，95%CI 0.83至1.25，一项研究，2992例婴儿），或研究中总体或分娩后60分钟内进行胎儿采血的患者中的代谢性酸中毒（RR 0.91，95%CI 0.60至1.36，一项研究，2675例婴儿）。在乳酸水平组或pH值组中，为进一步评估分娩期间胎儿健康状况而进行额外检测的胎儿比例相似（RR 0.22，95%CI 0.04至1.30，两项研究，3333例婴儿；Tau² 1.00，I² = 58%）。在报告了这一结果的一项研究中，胎儿采血测定乳酸水平和pH值的成功率分别为98.7%和79.4%。对于令人不安的胎儿状况，在所有女性中或在分娩后60分钟内采集胎儿血样的组中，出生方式或手术分娩方面组间无显著差异（例如，所有纳入者的剖宫产，RR 1.09，95%CI 0.97至1.22，两项研究，3319例女性；所有纳入者因胎儿状况令人不安而进行的手术分娩，RR 1.02，95%CI 0.93至1.11，一项研究，2992例女性）。两项研究均未报告胎儿头皮撕裂或产妇焦虑的不良反应。
当需要进一步检测以评估分娩期间胎儿健康状况时，胎儿头皮采血测定乳酸水平比pH值测定更有可能成功进行。进一步的研究可考虑按胎龄、分娩阶段以及第二产程延长时的采样进行亚组分析。此外，我们期待正在进行的研究结果，这些研究比较不采集胎儿血样与采集血样测定乳酸水平，并探讨长期新生儿结局、产妇对产时胎儿监测的满意度以及经济分析。
