Antepartum fetal assessment--newer techniques.

URING the past two decades, tremendous improvements in perinatal outcome have been achieved. This has occurred to a large extent from the ability to better evaluate the fetal environment. Initially, antepartum and intrapartum fetal heart rate monitoring were used to assess fetal condition. With the subsequent development of ultrasonography, the clinician is now afforded the opportunity to visualize the intrauterine environment and to conduct a fetal physical exam. While the use of fetal monitoring and ultrasonography have contributed greatly to the improvements in perinatal outcome, other factors such as enhanced neonatal care, regionalized referrals, increased safety of cesarean delivery, and the avoidance of birth trauma have also contributed to the improvements in health care for the pregnant woman and her fetus. Antepartum fetal heart rate monitoring has played an important role in the improvements in perinatal care. Initially, Hon and Quilligan demonstrated the relationship between certain fetal heart rate (FHR) patterns and subsequent fetal outcome. I.* The presence of a normal FHR pattern was associated with the virtual absence of an abnormal outcome. In his atlas on fetal heart rate monitoring, Hon2 demonstrated the association between late decelerations of the fetal heart rate (FHR) and fetal hypoxia. Subsequently, these concepts led to the application of continuous electronic fetal monitoring during labor in order to assess more accurately the fetal condition. These principles were then applied to a group of highrisk patients who underwent simulated labor with oxytocin prior to the onset of labor.3The goal of this initial antepartum fetal surveillance report was to identify those pregnancies at a greater risk of uteroplacental insufficiency. Once this relationship was established, the contraction stress test (CST) rapidly became a clinically useful and acceptable antepartum fetal surveillance technique.