LeRoy J. Dierker

Studies of antepartum behavioral state in the human fetus at term

Abstract This prospective study describes intrauterine behavioral states in the human fetus. The variables used are fetal movement and two expressions of fetal heart rate (FHR): long-term variability and baseline rate. Fetal movement was recorded with the use of two strain gauges. FHR was measured with a transabdominal fetal electrocardiographic processor. Sixteen fetuses of normal pregnant patients were studied near term. One-minute periods called “epochs” were classified as quiet, active, and intermediate, based on the presence or absence of fetal movement (longer in duration than one second), increased or decreased long-term FHR variability, and the baseline of the FHR. Complete agreement in epoch classification was noted in 79.3 per cent of the 2,054 epochs analyzed. Quiet and active one-minute epochs were clustered into longer time periods representing quiet and active fetal behavior states similar to those seen in the neonate. The overall visual evaluation of the tracings based on the above noted criteria demonstrated the presence of quiet, active, and transitional states in the fetus. Mean duration of a complete cycle, including the quiet, active, and transitional states, was 62.3 minutes. The mean duration in the quiet state was 22.8 minutes and the mean duration in the nonquiet states (active and transitional) was 39.5 minutes. The significance of these intrauterine behavioral states is stressed.

Outcomes of women presenting in active versus latent phase of spontaneous labor.

OBJECTIVE: To evaluate outcome differences between women presenting in latent and active labor. METHODS: We evaluated all low-risk women with term, singleton, vertex gestations who presented in active phase or latent phase labor at MetroHealth Medical Center from January 1993 to June 2001. Baseline characteristics were compared. Labor outcomes were assessed by logistic regression, controlling for parity. RESULTS: A total of 6,121 active phase and 2,697 latent phase women met the study criteria. More latent phase women were nulliparous (51 compared with 28%). Latent phase women had more cesarean deliveries (nulliparas 14.2% compared with 6.7%, multiparas 3.1% compared with 1.4%). Controlling for parity, latent phase women had more active phase arrest (odds ratio [OR] 2.2), oxytocin use (OR 2.3), scalp pH performed (OR 2.2), intrauterine pressure catheter placed (OR = 2.2), fetal scalp electrocardiogram monitoring (OR = 1.7), and amnionitis (OR 2.7) (P < .001 for each). CONCLUSION: It is uncertain whether inherent labor abnormalities resulted in latent phase presentation and subsequent physician intervention or early presentation and subsequent physician intervention are the cause of labor abnormalities. LEVEL OF EVIDENCE: III

Births to teenagers: Trends and obstetric outcomes

Objective To compare the trends and obstetric outcomes of pregnancy in teenage women with those of adult women. Methods We analyzed a 19-year (1975–1993) computerized perinatal data base with on 69,096 births collected prospectively from a single inner-city tertiary medical center. Results Of all the births, 1875 (2.7%) were to teenagers 12–15 years old and 17,359 (25.3%) were to teenagers 16–19 years old. Over the study period, the number and proportion of births to teenagers of both age groups declined (P < .001 in both cases). The proportions of teenagers 12–15 and 16–19 years old were highest among blacks (4.1% and 28.1%, respectively), followed by Hispanics (2.4%, 24.7%) and whites (1.6%, 23.1%). More than 95% of teenagers had no private health insurance coverage (staff), significantly higher than the 81.6% of mothers aged 20 years of older (P < .001). More than 8.1% of teenagers 12–15 years old had two or fewer prenatal care visits, significantly higher than 6.8% for teenagers 16–19 years old and 7.1% for adults (P < .001. The average gestational age and birth weight were significantly lower for teenagers 12–15 years old compared with those 16–19 years old and adults. Patients 16–19 years of age had longer gestational age and higher birth weight than the adults. The proportion of primary cesarean deliveries among teenagers 12–15 years old was 11.6%, significantly higher than 9.4% for those 16–19 years old and 10.2% for adults (P < .001). Conclusion On average, females 16–19 years old had better obstetric outcomes than adults, whereas obstetric outcomes for those 12–158 years old were worse than for adults. Therefore, all teenagers should not be grouped together when their obstetric outcomes are compared with those of adults.

Metabolism of urea and glucose in normal and diabetic pregnancy

Quantitative estimation of rates of urea synthesis, urea and nitrogen excretion and glucose production were done in ten normal, seven insulin-dependent diabetic and three gestationally diabetic subjects, after an overnight fast during the third trimester of pregnancy. Studies were repeated on three normal, three insulin-dependent diabetic, and two gestationally diabetic subjects during postpartum. [15N2]urea and [6,6-2H2]glucose tracers were infused simultaneously at constant rate for five hours from 12–17 hr of fasting. Plasma [15N2]urea and [2H2] glucose enrichments were measured by gas chromatograph-mass spectrometry. Rates of urea synthesis and glucose production were estimated during steady state by tracer dilution. Overnight fast resulted in a decline in plasma glucose. Extension of the fast by another 5 hr resulted in a further decrease in the levels of circulating glucose and rise in the level of betahydroxybutyrate in both normal and diabetic pregnant subjects. There was no significant difference in the plasma concentration of amino acids after 12 hr of overnight fast, between the normal and diabetic subjects during antepartum. However, a significant increase in the plasma concentration of amino acids occurred during the postpartum period. The plasma urea nitrogen concentration was reduced by 60% during antepartum period (8.22 ± 2.24 and 11.49 ± 3.16 mg/dl; mean ± SD). There was a corresponding decrease in the rate of urea nitrogen synthesis (4.17 ± 1.28 and 6.84 ± 2.52 mg/kg hr). In addition, the rates of urinary urea nitrogen and total nitrogen excretion were attenuated during pregnancy. In contrast, the ammonia excretion rate remained unchanged (0.24 ± 0.09 versus 0.23 ± 0.12 mg/kg hr) in the antepartum and postpartum period. Rigorous regulation of diabetes in pregnancy resulted in normalization of urea and glucose metabolism after an overnight fast. The plasma glucose concentration was reduced during pregnancy, while the rate of glucose production expressed per unit body weight was unchanged. The decreased urea synthesis rate during pregnancy resulted in an altered relationship between urea and glucose production rates. These data suggest conservation of amino nitrogen during pregnancy in humans, apparently for tissue protein synthesis. As ureogenesis is a concomitant of gluconeogenesis from amino acids, these data further suggest an attenuated hepatic gluconeogenesis following a brief 17 hr fast. The mechanism of these observations appears to be via decreased delivery of substrate to the liver for ureogenesis possibly as a result of diversion to the fetus.

A comparison between maternal, tocodynamometric, and real-time ultrasonographic assessments of fetal movement

Fetal movements were simultaneously studied with maternal perception, tocodynamometry, and real-time ultrasonography. A comparison between these three modalities demonstrated good agreement. The percentage of agreement improved with increasing duration of fetal movements. For fetal movements lasting longer than 3 seconds, the agreement between ultrasonography and tocodynamometry was 95.6%. These findings suggest that tocodynamometry is a sensitive method for studying fetal movements.

The midforceps: Maternal and neonatal outcomes

A retrospective review of midforceps deliveries occurring between 1976 and 1982 at a county teaching hospital is presented. Midforceps deliveries were performed in 0.8% of deliveries (176 of 21,414) during this period, a rate reflecting the general admonition against potentially traumatic injury to the infant. Under these conditions, midforceps deliveries were associated with active and second-stage labor abnormalities, abnormal fetal heart rate patterns, maternal perineal lacerations, low 1-minute Apgar scores, and neonatal cephalohematomas more frequently than were deliveries of the remainder of the patients. Epidural anesthesia was significantly associated with midforceps deliveries. Midforceps patients were matched to similar groups who were delivered by cesarean section or low forceps or who had spontaneous births. The findings do not document an increase in short-term neonatal morbidity in the midforceps group under the conditions described.

The clustering of fetal heart rate changes and fetal movements in pregnancies between 20 and 30 weeks of gestation

The temporal organization (nonrandomness) of fetal heart rate (FHR), fetal movement, and their association was evaluated in 20 normal pregnancies at 20 to 22 or 28 to 30 weeks of gestation with the use of external electronic fetal monitoring and statistical analysis with the runs test. At 20 to 22 weeks, significant clustering was found in one of 10 pregnancies for FHR change, two of 10 pregnancies for fetal movement, and one of 10 pregnancies for FHR changes associated with fetal movement. At 28 to 30 weeks, significant clustering was found in eight of 10 pregnancies for FHR change, eight of 10 pregnancies for fetal movement, and all 10 pregnancies of FHR change associated with fetal movement. There was significantly more clustering of FHR change, fetal movement, and FHR change associated with fetal movement at 28 to 30 weeks of gestation than at 20 to 22 weeks of gestation. Clustering of FHR changes was highly correlated with clustering of fetal movement.

Trends in an obstetric patient population: An eighteen-year study

OBJECTIVE Our goal was to evaluate various trends including gestational age, birth weight, and mode of delivery in an inner-city obstetric patient population delivered at a tertiary medical center. STUDY DESIGN We used an 18-year computerized perinatal database collected prospectively since 1975 in an inner-city tertiary medical center. More than 63,500 deliveries from 1975 through 1992 were evaluated. Trends in gestational age, birth weight, and mode of delivery were investigated with Cox-Stuart, regression, and other trend analysis methods. RESULTS The number of deliveries increased from 2682 in 1975 to 4740 in 1991, an increase of 77%. The median maternal age has increased from 20 years in 1975 to 23 years in 1992 (p < 0.001). Overall, the mean gestational age has declined monotonically from 39.2 +/- 2.84 weeks in 1975 to 38.3 +/- 3.17 weeks in 1992 (p = 0.057). While the median and lower percentiles of birth weight for singleton births have declined, the 75th and higher percentiles of birth weight have increased during 18 years. Overall, the proportion of preterm births (< 37 completed weeks gestational age) has increased from 3.3% in 1975 to 7.8% in 1991 (p < 0.001). During this period the proportion of low-birth-weight infants (< 2,500 gm) increased significantly from 12.7% to 17.3% (p < 0.001). The proportion of cesarean section deliveries for private patients has declined from 37% in 1975 to 25% in 1992 (p = 0.025), while this proportion has increased monotonically for staff patients from 10% to 17% during this period (p < 0.001). CONCLUSIONS Considering the large size of the database and diverse background of the study population, we believe that these trends can provide a realistic characterization of an obstetric patient population for a large inner-city urban population.

Human fetal respiratory movements: a technique for noninvasive monitoring with the use of a tocodynamometer.

A tocodynamometer applied to the maternal abdomen is used for monitoring human fetal respiratory movements (FRM). This provides a recording of fetal chest wall movements from which observations and measurements relating to fetal respiratory physiology may be made. The FRM must be differentiated from materanal vascular and respiratory movements, as well as fetal movements and cardiac pulsations. The technique lends itself to extended periods of observation, since it does not transmit energy to the fetus as in other techniques. The simplicity of the technique, combined with the use of monitoring devices already available in most hospitals, warrants further observation of this method of respiratory movement monitoring in the developing fetus.

Correlation between Gestational Age and Fetal Activity Periods

Cyclic patterns of active and quiet fetal activity were evaluated in 36 clinically normal gravidas between 27 and 42 weeks of gestation. All infants were subsequently delivered between 37 and 42 weeks of gestation, were clinically normal and of appropriate weight for gestational age. Active-quiet cycles occurred less frequently and were of longer duration with increasing gestational age. Regression analysis of the number of active-quiet cycles with gestational age yielded a correlation coefficient of 0.52 (p less than 0.01). The similarity of fetal active-quiet cycles and active and quiet sleep cycles observed after birth is noted.