Operative vaginal delivery (OVD) is a valuable technique that can be used to expedite delivery safely in instances of potential fetal or maternal compromise. It is often faster than cesarean delivery and has lower maternal and fetal morbidity as well. In their 2014 Obstetric Care Consensus for Safe Prevention of the First Cesarean, the American College of Obstetricians and Gynecologists (ACOG) and the Society of Maternal-Fetal Medicine (SMFM) recommend using OVD as a strategy to safely lower the primary cesarean rate. Critical elements of successful OVD include a skilled accoucheur, an acceptable indication, and the ability to anticipate and perform cesarean delivery if necessary. The hospitalist is in an ideal position to utilize this technique individually and to act as a consultant for other providers. This person also can be integral in teaching the technique to others, as he or she is often the most experienced provider in the labor suite.

The incidence of OVD has dropped substantially in recent decades, from 20% of deliveries in 1983 to 0.5% in 2015. Upon completion of their training, graduating residents have participated in an average of five forceps deliveries and eight vacuum-assisted deliveries. With such low numbers of procedures, it is understandable that obtaining sufficient competency in these procedures is a challenge. As more institutions are incorporating experienced hospitalists in their models of patient care, there is an opportunity to reverse the decline in OVD rates, which can result in a decrease in cesarean rates and its associated morbidities.

Knowledge of the anatomy of both the maternal pelvis and the fetal skull is critical to successful OVD. The safety of the procedure is greatly affected by correct identification of fetal position and station. The likelihood of success is affected by the degree to which the force vector of assistance both aligns with the birth canal and presents the smallest possible diameter of the fetal vertex through the pelvic outlet.

Correctly determining the position of the fetal vertex is a prerequisite to attempting OVD, and that is based on knowledge of the anatomy of the bones, sutures, and fontanelles of the fetal cranium. Generally, the anterior and posterior fontanelles, and midsagittal suture can be identified upon vaginal examination (Fig. 67-1), allowing the provider to determine the position of the baby, as well as to assess for asynclitism.

Visualizing the cardinal movements of labor (Fig. 67-2) is helpful in applying the correct traction vector to effectively assist descent through the birth canal. At higher stations, the fetal neck must remain flexed, and traction should be in an outward or even slightly downward direction (Fig. 67-3). As the widest part of the fetal vertex passes under the pubic symphysis, the traction vector begins to arc upward, allowing extension and delivery (Fig. 67-4).

The classification of OVD is based upon the station of the fetal vertex, which is defined in terms of centimeters above or below the ischial spines. For example, +2 station indicates that the leading bony point of the skull has reached 2 cm below the ischial spines. Midpelvic OVD is the designation applied to the situation where the fetal vertex is engaged but not reached +2 station. Low pelvic OVD is determined when the station is +2 or lower, but the conditions for outlet procedure has not been met. The low OVD procedures are subclassified in terms of the amount of rotation performed—either less than 45 degrees, such as left occiput anterior (LOA) to occiput anterior (OA) or greater than 45 degrees, (such as left occiput posterior (LOP) to OA. These subclassifications apply only to forceps deliveries, as the vacuum extractor should not be used as a rotational instrument. An outlet procedure is defined as the situation where the fetal skull has reached the pelvic floor and the fetal scalp is visible at the introitus between contractions.

The presence of an acceptable indication for OVD is one of the critical factors in determining success. In general, OVD is indicated when the medical benefits of shortening the second stage of labor outweigh the risks associated with the procedure. Acceptable indications for OVD include second stage arrest Category 2 or 3 FHR tracing remote from spontaneous vaginal delivery, and maternal conditions unconducive to prolonged Valsalva (e.g. cardiac/pulmonary/neurologic disease).

The standard contraindications to spontaneous vaginal delivery would also preclude OVD, along with unknown position of the vertex and a provider who lacks the proper training. Specifically for vacuum extraction, gestational age <34 weeks is a contraindication, given the risk of intracranial hemorrhage. Fetal thrombocytopenia, bone mineralization disorders (such as osteogenesis imperfecta), and bleeding disorders would be additional conditions recommending against OVD.

Prerequisites for successful OVD include a fully dilated cervix, knowledge of the position of the vertex, ruptured membranes, an engaged vertex, appropriate anesthesia (pudendal or epidural block), knowledge of the fetal heart rate (FHR), and an empty maternal bladder. Willingness to abandon the procedure in the event of failure is important. Notification of the pediatric and anesthesia services when considering OVD is helpful in terms of maintaining safe and effective communication on the labor unit. A patient who is cooperative with maternal expulsive efforts adds to the likelihood of a successful procedure, especially in the case of vacuum-assisted delivery. Table 67-1 lists the indications, contraindications, and prerequisites for OVD.).