Biomedical subjects
R H Hertz
Publications and source records attributed to R H Hertz.
Studies of antepartum behavioral state in the human fetus at term.
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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.
Fetal movements associated with fetal heart rate accelerations and decelerations.
In normal pregnant women, the relationship between the FHR and fetal movements (FM) was evaluated during 1,541 consecutive observed FM of at least 1 second's duration. Two observed FHR changes were: (1) accelerations and (2) accelerations followed by decelerations. An acceleration in FHR was observed in association with 91.2 per cent of all FM of 1 to 3 seconds' duration and with 99.8 per cent of FM of longer than 3 seconds' duration. FM were associated with an acceleration followed by a deceleration 66.7 per cent of the time. FM lasting longer than 1 second and associated with neither accelerations nor decelerations were seen 1.8 per cent of the time.
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.
Human fetal respiratory arrhythmia.
The association of human fetal respiration with the fetal heart rate was studied in 13 pregnant patients between Weeks 34 and 41 of pregnancy. Fetal respiration was recorded with the use of a tocodynamometer. Fetal heart rate was recorded with the use of ultrasound and abdominal fetal electrocardiogram monitoring devices. The results documented the presence of human fetal respiratory arrhythmia. An increase in fetal heart rate was seen during fetal "inspiration" followed by a decrease during "expiration." The possible mechanisms of the respiratory arrhythmia are discussed.
Diagnostic studies and fetal assessment in advanced extrauterine pregnancy.
Advanced extrauterine pregnancy occurs rarely and may present diagnostic difficulty. Failure to induce uterine contractions during oxytocin infusion is a well-established diagnostic technic. The present case suggests that additional newer technics for fetal assessment, including sonography, unstressed monitoring of the fetal heart rate, uterine contractions, fetal movements, and serial urinary estriol determinations may also be useful in diagnosing and managing such complex cas-s.
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.
Effects of acute maternal hypoxia and hyperoxia on the blood flow to the pregnant uterus.
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