In obstetrics, acronyms are frequently used to describe complex anatomical relationships. LOP stands for Left Occiput Posterior, defining a specific fetal position just before or during labor. This three-letter code communicates the baby’s orientation relative to the birthing parent’s pelvis. LOP is a type of fetal malposition, meaning the baby is head-down (vertex presentation) but is not in the most optimal alignment for delivery. Understanding this position is important because it can significantly influence the labor process and the need for interventions.
Decoding the Acronym LOP
The acronym LOP maps the baby’s position within the pelvis using three anatomical components. The first letter, “L,” signifies that the baby’s occiput, or the back of the head, is positioned toward the mother’s Left side. The second letter, “O,” stands for Occiput, identifying the presenting part of the fetus—the back of the baby’s skull—which leads the way through the birth canal.
The final letter, “P,” denotes Posterior, indicating the occiput is facing the mother’s back or spine. In the LOP position, the baby is facing the mother’s abdomen, with their back angled toward the mother’s left-rear quadrant. This contrasts with the ideal Left Occiput Anterior (LOA) position, where the baby’s occiput faces the mother’s front-left side, allowing the smallest diameter of the head to engage first.
LOP is a specific variant of the broader Occiput Posterior (OP) category. While many babies start in a posterior position, the goal is for them to naturally rotate into an anterior position as they descend. If the baby remains in the LOP position, the larger diameter of the head presents to the pelvis, complicating the mechanics of birth.
Implications for Labor and Delivery
The LOP position often presents challenges because the baby’s head does not fit the curve of the pelvis as efficiently as an anterior position. This alignment means the head acts as a less effective wedge to dilate the cervix, leading to less efficient and longer labor patterns. Both the first stage (cervical dilation) and the second stage (pushing phase) are frequently prolonged when the fetus is in a persistent LOP position.
The most common symptom is intense, localized back pain, often called “back labor.” This pain results from the baby’s hard occipital bone pressing directly against the mother’s sacrum with every contraction. The poor fit can lead to a higher risk of perineal tearing and significant blood loss after delivery, known as postpartum hemorrhage. If the baby fails to rotate, the likelihood of an operative delivery, such as using a vacuum extractor or forceps, or requiring a Cesarean section, increases substantially.
Strategies for Fetal Position Change
The primary goal of managing an LOP presentation is to encourage the baby to rotate into the more favorable anterior position. Non-invasive techniques use gravity and maternal movement to create space and facilitate this rotation. Simple positioning changes, such as spending time on hands and knees, leaning forward over a birth ball, or lunging, can help tilt the pelvis and draw the baby away from the spine.
Lying on the side corresponding to the baby’s back (the mother’s left side) is a common strategy to promote rotation. Hydrotherapy, like soaking in a warm tub, can also help relax the pelvic floor muscles, giving the baby more room to turn. If these non-medical methods are unsuccessful and labor stalls, medical interventions may be necessary for a safe delivery.
A healthcare provider may attempt a manual rotation, reaching into the birth canal to physically turn the baby’s head to an anterior position. If the baby is low enough in the pelvis, instruments like forceps or a vacuum may be used to assist with the rotation and delivery.