BACKGROUND:
The most common causes of lack of progress in the second stage of labor include cephalopelvic disproportion, abnormal uterine contractions, and abnormal fetal head presentation. The theory suggests that left-occiput anterior (LOA) position may be the the most favorable for the process of birth. However, there is currently no evidence regarding how right versus left the fetal position influences labor.

OBJECTIVES:
The aim of this study was to determine whether the risks of cesarean birth due to the lack of progress during the second stage of labor are higher among women with the right fetal position.

METHODS:
This case-control study included 3997 births (3730 controls, 267 cases). Logistic regression assessed factors associated with lack of labor progression in the second stage. To address group imbalance, an additional 1:1 and 1:5 random sampling was performed.

RESULTS:
After adjusting for other factors, including pre-induction, the use of oxytocin, amniotomy, gestational age, newborn's weight and length, right fetal positioning still increased the risk of lack of progress in the second stage of labor by more than threefold (OR = 3.70, p < 0.001). Administration of epidural analgesia was the protective factor, which reduced the risk of lack of progress almost tenfold (OR = 0.11, p < 0.001).

CONCLUSIONS:
These results indicate that a right fetal position is a significant risk factor for lack of progress in the second stage of labour. The mechanism by which epidural analgesia may act as a protective factor requires further investigation. Furthermore, our findings suggest a need for research to determine the extent to which fetal position can be influenced in late pregnancy. Promoting a left fetal position could potentially improve perinatal outcomes and decrease the caesarean section rate.

KEY MESSAGE:
Right fetal position is a significant risk factor for lack of progress in the second stage of labour. Poster session 2 (Group A)