Pardey Angela J, Phipps Hala, Eames Amanda, Hyett Jon, Kuah Sabrina, De Vries Bradley
Department of Obstetrics and Gynaecology, Royal Prince Alfred Hospital, Sydney, AUS.
Department of Obstetrics and Gynaecology, Sydney Institute for Women, Children and Their Families, Sydney Local Health District, Sydney, AUS.
Cureus. 2024 May 30;16(5):e61358. doi: 10.7759/cureus.61358. eCollection 2024 May.
Fetal head position significantly influences birth outcomes, with higher rates of complications observed when the fetal head is in the Occiput Posterior (OP) position compared to Occiput Transverse (OT) or Occiput Anterior (OA) positions. There is no consensus in the current literature on the precise rotational point at which the fetal occiput shifts from posterior to transverse, reducing clarity in both scientific and clinical communication. Different studies employ varying definitions of these positions, which affects management decisions. This study aims to determine if a definable threshold exists between the directly posterior and directly transverse positions that correlates with different birth outcomes, thereby proposing a consistent and clinically useful definition for OP versus OT. We analyzed ultrasound data from 570 patients at full dilatation from five previous studies, correlating the angle of the fetal occiput (noted on a clock-face) with birth outcomes. Adverse outcomes were defined as cesarean delivery, instrumental vaginal delivery, significant postpartum hemorrhage (500 ml or more), obstetric anal sphincter injury, five-minute Apgar scores <7, arterial cord pH <7, base excess less than -12, or neonatal intensive care unit admission. The analysis was conducted using SAS version 9.4. The study found a continuous relationship between the fetal occipital angle and adverse birth outcomes without a distinct threshold separating OP from OT positions. No clear inflection point was demonstrated in pregnancy outcomes between OT and OP. The relationship between the angle of occiput position and pregnancy outcomes was continuous: the closer the fetal head was to directly OP, the higher the likelihood of adverse outcomes. Given the lack of a clear cut-off and to improve consistency in future research, we recommend dividing the occiput position into four quadrants of 90 degrees each. This classification could standardize reporting and potentially improve clinical decision-making regarding fetal position during labor.
胎儿头部位置对分娩结局有显著影响，与枕横位（OT）或枕前位（OA）相比，当胎儿头部处于枕后位（OP）时，并发症发生率更高。目前的文献对于胎儿枕骨从后位转变为横位的确切旋转点尚无共识，这在科学和临床交流中都降低了清晰度。不同的研究对这些位置采用了不同的定义，这影响了管理决策。本研究旨在确定在直接后位和直接横位之间是否存在一个可定义的阈值，该阈值与不同的分娩结局相关，从而为OP与OT提出一个一致且临床有用的定义。我们分析了来自之前五项研究的570例宫颈完全扩张患者的超声数据，将胎儿枕骨角度（按钟面记录）与分娩结局相关联。不良结局定义为剖宫产、器械助产阴道分娩、大量产后出血（500毫升或更多）、产科肛门括约肌损伤、5分钟阿氏评分<7、脐动脉血pH<7、碱剩余小于-12或新生儿重症监护病房入院。分析使用SAS 9.4版本进行。研究发现胎儿枕骨角度与不良分娩结局之间存在连续关系，没有明显的阈值将OP与OT位置区分开来。OT和OP之间的妊娠结局未显示出明确的转折点。枕骨位置角度与妊娠结局之间的关系是连续的：胎儿头部越接近直接OP位，不良结局的可能性越高。鉴于缺乏明确的分界点，为了提高未来研究的一致性，我们建议将枕骨位置分为四个90度的象限。这种分类可以规范报告，并可能改善分娩期间关于胎儿位置的临床决策。
