Roger H. Hertz

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.

Classification of human fetal movement

A study of fetal activity was undertaken as the first step in a series of physiologic fetal movement studies. A simple, safe, noninvasive, clinically applicable method for studying fetal movement with a tocodynamometer is described. Four basic types of fetal movement have been seen and defined in terms of their durations, recorded patterns, and descriptive terminologies for identifying each movement.

Diagnosis of Gestational Diabetes in Early Pregnancy

Objective To determine whether glucose intolerance can be identified early in gestation in a high-risk population so that early intervention can be planned to prevent associated morbidity. Research Design and Methods After appropriate dietary preparation, patients with a high risk for gestational diabetes underwent a 50-g oral glucose screening test during fasting. Patients were tested on enrollment and every 10 wk until delivery. Those with a 1-h plasma glucose value of ≥7.5 mM underwent a 100-g oral glucose tolerance test. Gestational diabetes was based on either a markedly abnormal 50-g screening test or abnormal 100-g oral glucose tolerance test. Results Ten of 15 (66%) patients who developed gestational diabetes were diagnosed during the first half of the pregnancy. Six were diagnosed in the first trimester. If the definition of an abnormal 1-h plasma glucose value was lowered from 7.5 to 7.2 mM, an additional 2 patients could have been identified in the first trimester with an improvement in sensitivity from 70 to 91% with only a slight drop in specificity (from 91 to 88%). Diagnosis of gestational diabetes was not enhanced by measuring plasma insulin concentrations or insulin-glucose molar ratios. Conclusions The diagnosis of gestational diabetes in a high-risk population can be made in the first half of pregnancy. Early diagnosis should permit evaluation of intervention strategies, which may result in improved perinatal outcome.

Should all pregnant women be screened for hepatitis B

To assess the sensitivity of historical risk factors for identification for hepatitis B surface antigen (HBsAg)-positive parturients, 4399 pregnant women were consecutively screened for HBsAg. Information regarding risk for hepatitis B infection was obtained from each HBsAg-positive parturient. Twenty-three HBsAg-positive subjects were identified (5.2/1000 deliveries). The HBsAg carrier rate (18/2231, or 8.1/1000 deliveries) was significantly higher in women of black, Asian, or Hispanic origin than in the remaining ethnic groups (non-Hispanic whites plus all others, 5/2168, or 2.3/1000 deliveries) (chi square, 5.95; p = 0.016). Risk factors for identification of HBsAg-positive women were present in 10 of 22 asymptomatic subjects (sensitivity, 45%; 95% confidence interval, 24% to 68%). Much of the information required to assess one of these risk factors, previous infection, involved detailed questioning and is unlikely to be obtained in the context of conventional obstetrical care. Routine maternal HBsAg screening programs may be needed if transmission of hepatitis B from mother to infant is to be prevented.

Clinical estimation of gestational age: rules for avoiding preterm delivery.

Reliable knowledge of the duration of pregnancy prior to birth is often of crucial importance in making obstetric care decisions. Laboratory methods for estimating fetal maturity have received considerable attention, but the usefulness of historical information has only rarely been addressed. In order to examine the value of clinical estimators of fetal gestational age (GA) in 690 pregnancies, the correlations of menstrual history (LMP), first unamplified audible fetal heart tones (FFH), and quickening (Q), with GA, based on the modified Dubowitz examination at birth, were examined. Evaluation of each of the data sets used alone reveals that in order to be 90% certain that an infant will be mature at delivery (greater than or equal to 38 weeks), a reliable LMP must have been noted for 42 weeks prior to birth, the FFH heard for 21 weeks, and Q felt for 25 weeks. These findings suggest that carefully obtained historical and physical examination information remains a cornerstone of appropriate obstetric care.

Regular and irregular human fetal respiratory movement

Fetal respiratory movements (FRM) were studied using abdominal strain gauges (tocodynamometers). The patterns of the FRM were evaluated during both active and quiet fetal time periods, which were determined by the fetal heart rate (FHR) and fetal body movement (FM). The FRM were classified into Regular and Irregular patterns based on neonatal respiratory criteria for sleep-state studies in the term infant. Evaluation of the breath-to-breath intervals (BBI) showed statistically significant respiratory differences during active and quiet fetal time periods. Irregular fetal respiratory movement patterns were noted during fetal active periods. It would appear that the correlation of regular fetal respiratory movement with fetal quiet periods in the term fetus adds additional evidence that a quiet sleep state may exist in the term 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.

Antenatal investigation of human fetal systolic time intervals

A noninvasive method for measuring the antenatal human fetal systolic time intervals with the use of the transabdominal fetal electrocardiogram and Doppler cardiogram is described. Unique interactive computer routines were developed for rapid and accurate determination of the pre-ejection period (PEP), ventricular ejection time (VET), PEP/VET ratio, and fetal heart rate (FHR). Thirty normal patients were monitored between 20 and 40 weeks of gestation. A regression analysis of the fetal systolic time intervals and FHR against gestational age was done. PEP and PEP/VET ratio were significantly correlated to the gestational age, while VET and FHR were not.

Management of third-trimester diabetic pregnancies with the use of continuous subcutaneous insulin infusion therapy: A pilot study

Six women with juvenile-onset diabetes were managed as outpatients during the third trimester of pregnancy with continuous subcutaneous insulin infusion therapy. Twenty-four-hour metabolic profiles for plasma glucose, beta-hydroxybutyrate, and triglycerides were monitored prior to, 1 week, 5 weeks, and 10 weeks after initiation of continuous subcutaneous insulin infusion therapy and compared with the metabolic profiles of 10 normal (nondiabetic) pregnant women. Near-normal metabolic profiles were achieved in these patients after 5 weeks of therapy in this pilot study. Patient motivation, compliance, and understanding of their illness were crucial in achieving the therapeutic goals of normoglycemia.

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.