Abstract：
OBJECTIVE: Current guidelines provide little supporting literature for the definition of uterine tachysystole during labour and no distinction is made for optimal contraction frequency depending on the clinical situation. We hypothesize that fetal hypoxia is frequently caused by uterine tachysystole and that high uterine contraction frequencies are especially harmful when fetal heart rate (FHR) abnormalities are present. We studied the association between contraction frequency and fetal scalp pH values in women with an indication for fetal blood sampling (FBS) based on FHR abnormalities.
METHODS: A retrospective study including 762 women was performed in a tertiary teaching hospital in the Netherlands from January 2015 until January 2020. Women with a singleton pregnancy with a gestational age ≥ 34+0 weeks were included when FBS was performed because of suspicious or pathological FHR tracings. Exclusion criteria were maternal age < 18 years, failed fetal scalp pH values, lack of thirty minute registration by tocodynamometry prior to FBS, poor quality of uterine monitoring, intrauterine resuscitation in the thirty minutes prior to FBS, maternal body mass index ≥ 30 kg/m2 and neonatal birth weight < 10th percentile. Uterine contractions in the thirty minutes prior to FBS were manually annotated by a researcher who was blinded to FBS values, FHR and other obstetrical data. Linear and logistic analysis were used to explore the association between uterine contraction frequency and FBS results.
RESULTS: Low fetal scalp pH values were significantly associated with contraction frequency prior to FBS. Fetuses of women with four to five contractions per ten minutes prior to FBS were 2.4 times more likely to have hypoxia as compared to fetuses of women with two to three contractions per ten minutes (aOR 2.4, 95% CI 1.1-5.4). With increasing contraction frequency, the risk of fetal hypoxia further increased.
CONCLUSIONS: Contraction frequency above four per ten minutes prior to FBS is significantly associated with fetal hypoxia in women with FHR abnormalities. We suggest to aim for a maximum contraction frequency of four per ten minutes in these women.
METHODS: A retrospective study including 762 women was performed in a tertiary teaching hospital in the Netherlands from January 2015 until January 2020. Women with a singleton pregnancy with a gestational age ≥ 34+0 weeks were included when FBS was performed because of suspicious or pathological FHR tracings. Exclusion criteria were maternal age < 18 years, failed fetal scalp pH values, lack of thirty minute registration by tocodynamometry prior to FBS, poor quality of uterine monitoring, intrauterine resuscitation in the thirty minutes prior to FBS, maternal body mass index ≥ 30 kg/m2 and neonatal birth weight < 10th percentile. Uterine contractions in the thirty minutes prior to FBS were manually annotated by a researcher who was blinded to FBS values, FHR and other obstetrical data. Linear and logistic analysis were used to explore the association between uterine contraction frequency and FBS results.
RESULTS: Low fetal scalp pH values were significantly associated with contraction frequency prior to FBS. Fetuses of women with four to five contractions per ten minutes prior to FBS were 2.4 times more likely to have hypoxia as compared to fetuses of women with two to three contractions per ten minutes (aOR 2.4, 95% CI 1.1-5.4). With increasing contraction frequency, the risk of fetal hypoxia further increased.
CONCLUSIONS: Contraction frequency above four per ten minutes prior to FBS is significantly associated with fetal hypoxia in women with FHR abnormalities. We suggest to aim for a maximum contraction frequency of four per ten minutes in these women.
摘要：
目的：目前的指南对分娩过程中子宫收缩快的定义提供的支持文献很少，并且根据临床情况对最佳收缩频率没有区分。我们假设胎儿缺氧通常是由子宫收缩过快引起的，并且当存在胎儿心率（FHR）异常时，高子宫收缩频率尤其有害。我们研究了基于FHR异常有胎儿血液采样（FBS）指征的女性的收缩频率与胎儿头皮pH值之间的关系。
方法：2015年1月至2020年1月在荷兰一家三级教学医院进行了一项包括762名女性的回顾性研究。由于可疑或病理性FHR追踪而进行FBS时，包括胎龄≥340周的单胎妊娠妇女。排除标准为产妇年龄<18岁，失败的胎儿头皮pH值，在FBS之前缺乏三十分钟的足力计记录，子宫监测质量差，在FBS前三十分钟进行宫内复苏，孕妇体重指数≥30kg/m2，新生儿出生体重<10百分位数。FBS前三十分钟的子宫收缩由一名对FBS值不知情的研究人员手动注释，FHR和其他产科数据。线性和逻辑分析用于探讨子宫收缩频率与FBS结果之间的相关性。
结果：低胎儿头皮pH值与FBS前的收缩频率显著相关。FBS前每十分钟有4至5次收缩的女性胎儿缺氧的可能性是每十分钟有2至3次收缩的女性胎儿的2.4倍(aOR2.4,95%CI1.1-5.4)。随着收缩频率的增加，胎儿缺氧的风险进一步增加。
结论：FBS前每十分钟超过4次的收缩频率与FHR异常女性的胎儿缺氧显著相关。我们建议这些女性的最大收缩频率为每十分钟四次。
方法：2015年1月至2020年1月在荷兰一家三级教学医院进行了一项包括762名女性的回顾性研究。由于可疑或病理性FHR追踪而进行FBS时，包括胎龄≥340周的单胎妊娠妇女。排除标准为产妇年龄<18岁，失败的胎儿头皮pH值，在FBS之前缺乏三十分钟的足力计记录，子宫监测质量差，在FBS前三十分钟进行宫内复苏，孕妇体重指数≥30kg/m2，新生儿出生体重<10百分位数。FBS前三十分钟的子宫收缩由一名对FBS值不知情的研究人员手动注释，FHR和其他产科数据。线性和逻辑分析用于探讨子宫收缩频率与FBS结果之间的相关性。
结果：低胎儿头皮pH值与FBS前的收缩频率显著相关。FBS前每十分钟有4至5次收缩的女性胎儿缺氧的可能性是每十分钟有2至3次收缩的女性胎儿的2.4倍(aOR2.4,95%CI1.1-5.4)。随着收缩频率的增加，胎儿缺氧的风险进一步增加。
结论：FBS前每十分钟超过4次的收缩频率与FHR异常女性的胎儿缺氧显著相关。我们建议这些女性的最大收缩频率为每十分钟四次。
