Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
Department of Pediatrics, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada.
Am J Obstet Gynecol. 2021 Jun;224(6):613.e1-613.e10. doi: 10.1016/j.ajog.2020.12.002. Epub 2020 Dec 9.
One of the controversies in the management of twin gestations relates to mode of delivery, especially when the second twin is in a nonvertex presentation (Vertex/nonVertex pairs) and birth is imminent at extremely low gestation.
We hypothesized that, for Vertex/nonVertex twins born before 28 weeks' gestation, cesarean delivery would be associated with a lower risk of adverse neonatal outcomes than trial of vaginal delivery. Our aim was to test this hypothesis by comparing the neonatal outcomes of Vertex/nonVertex twins born before 28 weeks' gestation by mode of delivery using a large national cohort.
This work is a retrospective cohort study of all twin infants born at 24 to 27 weeks' gestation and admitted to level III neonatal intensive care units participating in the Canadian Neonatal Network (2010-2017). Exposure is defined a trial of vaginal delivery for Vertex/nonVertex twins. Nonexposed (control) groups are defined as cases where both twins were delivered by cesarean delivery, either in vertex or nonvertex presentation (control group 1) or owing to the nonvertex presentation of the first twin (control group 2). Outcome measures are defined as a composite of neonatal death, severe neurologic injury, or birth trauma.
A total of 1082 twin infants (541 twin pairs) met the inclusion criteria: 220 Vertex/nonVertex pairs, of which 112 had a trial of vaginal delivery (study group) and 108 had cesarean delivery for both twins (control group 1); 170 pairs with the first twin in nonvertex presentation, all of which were born by cesarean delivery (control group 2); and 151 pairs with both twins in vertex presentation (vertex or nonvertex). In the study group, the rate of urgent cesarean delivery for the second twin was 30%. The rate of the primary outcome in the study group was 42%, which was not significantly different compared with control group 1 (37%; adjusted relative risk, 0.93; 95% confidence interval, 0.71-1.22) or control group 2 (34%; adjusted relative risk, 1.20; 95% confidence interval, 0.92-1.58). The findings remained similar when outcomes were analyzed separately for the first and second twins.
For preterm Vertex/nonVertex twins born at <28 weeks' gestation, we found no difference in the risk of adverse neonatal outcome between a trial of vaginal delivery and primary cesarean delivery. However, a trial of vaginal delivery was associated with a high rate of urgent cesarean delivery for the second twin.
双胎妊娠管理中的一个争议涉及分娩方式，尤其是当第二胎儿呈非头位（头位/非头位对）且在极低孕龄即将分娩时。
我们假设，对于 28 周前出生的头位/非头位双胞胎，与阴道试产相比，剖宫产分娩与新生儿不良结局的风险较低。我们的目的是通过比较加拿大新生儿网络（2010-2017 年）参与的三级新生儿重症监护病房中 24 至 27 周出生的所有双胎婴儿的分娩方式，用一个大型的全国队列来检验这一假设。
这是一项对所有 24 至 27 周出生并入住加拿大新生儿网络（2010-2017 年）参与的三级新生儿重症监护病房的双胎婴儿的回顾性队列研究。暴露被定义为头位/非头位对的阴道试产。未暴露（对照组）组定义为第一双胞胎呈非头位，而第二双胞胎经剖宫产分娩（对照组 1）或因第一双胞胎呈非头位而经剖宫产分娩（对照组 2）。结局指标定义为新生儿死亡、严重神经损伤或分娩创伤的复合结局。
共有 1082 例双胎婴儿（541 对）符合纳入标准：220 对头位/非头位对，其中 112 例接受阴道试产（研究组），108 例第一双胞胎呈非头位而第二双胞胎行剖宫产分娩（对照组 1）；170 对第一胎儿呈非头位，均行剖宫产分娩（对照组 2）；151 对双胎儿均呈头位（头位或非头位）。在研究组中，第二胎儿紧急剖宫产的发生率为 30%。研究组的主要结局发生率为 42%，与对照组 1（37%；调整后相对风险，0.93；95%置信区间，0.71-1.22）或对照组 2（34%；调整后相对风险，1.20；95%置信区间，0.92-1.58）相比，差异无统计学意义。当分别对头位和非头位的第一和第二胎儿的结局进行分析时，结果仍然相似。
对于 28 周前出生的头位/非头位早产儿，我们发现阴道试产与初次剖宫产分娩的新生儿不良结局风险无差异。然而，阴道试产与第二胎儿紧急剖宫产的发生率较高相关。
