State control in the substance-exposed fetus. I. The fetal neurobehavioral profile: an assessment of fetal state, arousal, and regulation competency.

Behavioral states are stable structures of behaviors that become more definable and coordinated with increasing age. With ultrasound we can see the fetus move, breathe, and react to changes in its environment. Ultrasound used in conjunction with Doppler fetal heart rate recording provides behavioral and neurophysiologic data useful in state determination. The Fetal Neurobehavioral Profile (FNP) was developed by our group as an assessment of fetal behaviors reflecting CNS integrity in the drug-exposed fetus. The FNP was designed to parallel methods of examining the newborn infant, especially in state-related behaviors. The FNP measures: fetal responsiveness and arousal after environmental perturbation with vibroacoustic stimulation (VAS); habituation to VAS; state recovery; and self-regulation post-VAS. From the behavioral and physiologic recordings, the constructs of state differentiation, organization, and regulation as well as fetal arousal and regulation competency can be measured. Previous work using the FNP showed that those fetuses with abnormal or suspect fetal state regulation demonstrated impaired performance on the NBAS (Am. J. Obstet. Gynecol. 161: 685, 1989). To expand these observations, three populations are currently being studied: prenatal nicotine-exposed, prenatal cocaine-exposed, and controls. Data are from 97 women/fetus dyads and a total of 236 FNP at ages 28-30 weeks gestational age, 31-34 weeks gestational age, and > 36 weeks gestational age. Although there are no group differences in the ability to achieve state by 36 weeks, interesting trends emerge: fetuses prenatally cocaine-exposed spend less time in 1F, more time in 4F and have fewer transitions. At FNP, fewer cocaine-exposed fetuses had an initial reaction to VAS, whereas fewer nicotine-exposed fetuses habituated. Although the ability to habituate to VAS did not discriminate the cocaine group from the control or nicotine groups, the number of stimuli required for habituation differed between groups: 7 for the cocaine-exposed, 3 for the nicotine, and 5 for the control groups. Thus latency, a measure of arousal, differs among the groups Preliminary data also suggest a correlation of prenatal data with postnatal outcome.