Perinatal antecedents of cerebral palsy.

The dramatic reduction in perinatal morbidity and mortality over the last decade has not been accompanied by any diminution in the incidence of cerebral palsy. We investigated retrospectively the relationship of certain perinatal events to the subsequent development of cerebral palsy in 75 infants. Cerebral palsy occurred in association with acute intrapartum asphyxia in 8% and traumatic delivery in 11%. Thirty-five percent of cases were associated with chronic fetal distress, defined by a unique fetal heart rate (FHR) pattern consisting of a normal baseline rate with persistently absent variability and mild variable decelerations with overshoot. This pattern was found frequently in association with postmaturity, meconium staining, intrauterine growth retardation, and neonatal seizures. Acid-base studies, when available, did not reveal acidosis. Twenty-seven percent of the cases involved a combination of chronic fetal distress, acute intrapartum fetal asphyxia, and/or traumatic delivery. We postulate that antenatal intermittent umbilical cord compression secondary to oligohydramnios results in repetitive transient central nervous system ischemia, insufficient to cause death, but resulting in a characteristic FHR pattern and impaired neurologic development. If these data are confirmed, this FHR pattern may be an important marker for the development of subsequent neurologic handicap or other adverse outcome.

Fetal heart rate patterns and the timing of fetal injury.

We studied the nonstress test (NST) results and other perinatal features of 44 children with cerebral palsy, who had fetal heart rate (FHR) patterns during labor suggesting preexisting injury. This was a retrospective, descriptive study. All fetuses persistently showed absent variability and small, variable decelerations, with overshoot from the onset of monitoring during labor. During the initial NST, 84.1% of fetuses revealed normal reactive NST patterns (three with decelerations). Six fetuses (15.9%) had nonreactive NST results (three with decelerations). The conversion of the reactive NST to a pattern of persistently absent variability often occurred during advanced pregnancy (average estimated gestational age 40 weeks), in association with decreased amniotic fluid (AF) volume (70.5%) and maternal complaints of decreased fetal movement (52.4%). FHR decelerations consistent with acute fetal distress were uncommon during early labor but occurred in about half of cases in advanced labor. All but one neonate had low Apgar scores at birth, but acidosis occurred in about one third of infants. Seizures developed in about half the infants, usually in the first day. Follow-up studies revealed a high incidence of mental retardation, microcephaly, and seizure activity in addition to cerebral palsy, regardless of the presence of perinatal acidosis. The results of this retrospective study of a limited population base suggest that fetal neurologic injury preceding labor may develop late in pregnancy, and that decreased AF volume appears to be a significant risk factor. FHR patterns may provide clues to the presence and timing of fetal neurologic injury.

Community-based perinatal research.

A program of clinical perinatal research was established in a community-based hospital in collaboration with private-practice obstetricians and their patients. This longitudinal study, undertaken to investigate the value of a circulating placental protein as an indicator of fetal compromise, enrolled 200 unselected pregnant patients. The project required collection of five blood samples at 16, 20, 24, 28, and 32 weeks' gestation in addition to a level II ultrasound examination at 32 weeks. Baseline and interim prenatal visit data were collected, as were maternal and neonatal data upon delivery. Patients who participated were invariably enthusiastic about their involvement. The physicians and their staff were also generally pleased. We infer from these and other studies a need to provide enhanced educational, participatory opportunities to all pregnant women. We conclude that properly conducted, reasonably funded projects that offer no direct benefit to the patient or physician can be successfully carried out with physicians and their private patients in community hospitals. The potential benefits of developing such extended resources can only enhance medical care and foster satisfaction and cooperation among physicians and patients.

Fetal head and abdominal circumferences: ellipse calculations versus planimetry.

One hundred twenty-two images of fetal heads and abdomens were obtained by ultrasound. The head and abdominal circumferences and their ratios were determined by planimetry and by the ellipse method utilizing four different equations. The accuracy of these equations was assessed by regressing the circumferences and ratios obtained by the equations against those measured by planimetry. All equations were found to be equally accurate in calculating head and abdominal circumferences and the head-to-abdomen circumference ratio. Compared to planimetry, the ellipse method is more accurate in calculating circumferences than when calculating their ratio.

Fetal head and abdominal circumferences: effect of profile shape on the accuracy of ellipse equations.

Images of 122 fetal heads and abdomens were obtained with ultrasound for the determination of head and abdominal circumferences. The profile shapes were characterized by the cephalic or abdominal index (D1/D2 x 100), D1 and D2 being the shortest and longest diameters of either the head or abdomen. The mean of the cephalic index was 79.1% +/- 5.2%, and that of the abdominal index was 89.1% +/- 7.0%. All equations were equally accurate in calculating head and abdominal circumferences regardless of the profile shape. Therefore, the simplest equation, (D1 + D2) x 1.57, should be utilized when calculating circumferences except in situations of extreme dolichocephaly.