Sekulic Slobodan, Stilinovic Nebojsa, Baturan Branislava, Krsman Anita, Tesic Igor, Vejnovic Aleksandra, Petrovic Djordje, Nikolasevic Zeljka, Mijavec Anna, Pesic Vesna, Petkovic Branka
Department of Neurology, University Clinical Center of Vojvodina, Novi Sad, Serbia.
Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia.
Front Med (Lausanne). 2023 Jun 21;10:1160229. doi: 10.3389/fmed.2023.1160229. eCollection 2023.
Breech presentation (BP) results from at random filling of the intrauterine cavity, with an equal probability for a BP or cephalic presentation (CP). Each fetus in BP has its "pair" in CP randomly assumed CP. Direct comparison of BP and CP makes bias to less expressed differences between these two groups. It is therefore necessary to subtract the number of fetuses/newborns from the CP set that are identical to the number of fetuses/newborns in the BP set, with identical characteristics, and add this group to the BP set before comparing them to the rest of the CP fetuses/newborns in the matching process.
The procedure encompasses nine variables in pregnancies with a congenitally malformed uterus (CMU) identified at the Department of Obstetrics (1985-2014): gestational age, birth mass, birth length, head circumference, shoulders circumference, umbilical length, placental weight, newborn mass/newborn length ratio, and newborn mass/placental mass ratio. Firstly, the probability of BP was determined and its relation to gestational age, physical characteristics, and previous presentations. Then direct comparison as well as case-control matching of the CP and BP were performed. Case-control matching was based on either a single specific variable (M1) or all combined variables (M2).
462 deliveries were identified with CMU. In 81 cases of multiparity, a fetal presentation was found to be an independent event regardless of the previous presentation, gestational age, and newborn physical characteristics. In four types of CMU with 337 deliveries (Bicornuate, Didelphys, Unicornuate, Arcuate), 9 variables with 36 instances of comparison were observed. M1 in 10 instances and M2 in 6 instances showed a statistically significant lower value of breech/random presentation compared with CP. CP have lower value in 2 instances in M1 and 1 in M2. Statistically significant differences were absent without the matching process.
The study confirms the maximum probability for the BP is 50%. The case-control matching procedure shows that it is able to detect the difference between the breech/random presentation and CP, while the classic method of direct comparison was unable to detect any differences. The outcome of the breech/random presentation in CMU should be evaluated with the described case-control matching procedure.
臀位分娩（BP）是由于子宫腔内随机填充所致，臀位分娩与头位分娩（CP）的概率相等。每个臀位胎儿都有一个在头位分娩中随机假设的“配对”头位胎儿。直接比较臀位分娩和头位分娩会使两组之间不太明显的差异产生偏差。因此，有必要从与臀位分娩组中胎儿/新生儿数量相同且特征相同的头位分娩组中减去这些胎儿/新生儿数量，并在匹配过程中将该组添加到臀位分娩组中，然后再将其与匹配的头位分娩组中的其余胎儿/新生儿进行比较。
该程序涵盖了产科（1985 - 2014年）确定的先天性子宫畸形（CMU）妊娠中的九个变量：孕周、出生体重、出生身长、头围、肩围、脐带长度、胎盘重量、新生儿体重/新生儿身长比以及新生儿体重/胎盘重量比。首先，确定臀位分娩的概率及其与孕周、身体特征和既往分娩情况的关系。然后对头位分娩和臀位分娩进行直接比较以及病例对照匹配。病例对照匹配基于单个特定变量（M1）或所有组合变量（M2）。
共确定462例先天性子宫畸形分娩病例。在81例经产妇中，发现胎儿胎位是一个独立事件，与既往分娩情况、孕周和新生儿身体特征无关。在四种类型的先天性子宫畸形（双角子宫、双子宫、单角子宫、弓形子宫）的337例分娩中，观察到9个变量，共36次比较。在10次M1匹配和6次M2匹配中，与头位分娩相比，臀位/随机胎位的数值在统计学上显著较低。在M1匹配中有2次、M2匹配中有1次头位分娩的数值较低。在不进行匹配过程时，无统计学显著差异。
该研究证实臀位分娩的最大概率为50%。病例对照匹配程序表明，它能够检测出臀位/随机胎位与头位分娩之间的差异，而经典的直接比较方法无法检测到任何差异。先天性子宫畸形中臀位/随机胎位的结果应采用所描述的病例对照匹配程序进行评估。
