- Email: [email protected]
Ultrasonic measurement of rate and depth of human fetal breathing: Effect of glucose
De Muylder
mother occur
et al.
but also by the in the postoperative
In conclusion, of postoperative chronic enough
October 1, 1983 Am. J. Obstet. Gynecol.
this
metabolic imbalances period.“, 7
study
showed
recuperation
are
maternal-fetal for interpretation
that
known
at least
necessary
animal preparation of data on fetal
before
to
3 days the
is stable myocardial
function. We are grateful for the technical assistance provided by Mrs. Janie Prosmane, Marie-ThCrPse Rabeau, and Marguerite P.-M&g&las and for the cooperation of Ms. M. Raymond in typing the manuscript. REFERENCES 1. Evers, J. L. H.: Cardiac pre-ejection period during prenatal life, Gynecol. Obstet. Invest. 11:193, 1980. 2. Organ, L. G., Milligan, J. E., Goodwin, J. W., and Bain, M. 1. C.: The pre-eiection period of the fetal heart: Response to stress in ;he term fetal lamb, AM. J. OBSTET. GYNECOL. 115:377, 1973. 3. Murata, Y., Miyake, K., and Quiligan, E. J.: Pre-ejection period of cardiac cycles in fetal lamb, AM. J. OBSTET. GYNECOL. 133:509. 1979.
4. Murata, Y., Martin, C. B., Jr., Ikenoue, T., and Petrie, R. H.: Cardiac systolic time intervals in fetal monkeys: Ventricular ejection time, AM. J. OBSTET. GYNECOL. 136: 603, 1980. 5. Murata, Y., Martin, C. B., Jr., Ikenoue, T., and Petrie, R. H.: Cardiac systolic time intervals in fetal monkeys: Pre-ejection period, AM. J. OBSTET. GYNECOL. 132:285, 1978. 6. Clapp, J. F., III, Abrams, R. M., and Patel, N.: Fetal metabolism during recovery from surgical stress, Gynecol. Invest. 8:299, 1977. 7. Gresham, E. L., Rankin, J. H. G., Makowski, E. L., Meschia, G., and Battaglia, F. C.: An evaluation of fetal renal function in a chronic sheep preparation, J. Clin. Invest. 51:149, 1972. J. C., Korcaz, Y., and Leduc, B.: Cardiovascular 8. Fouron, changes associated with fetal breathing, AM. J. OBSTET. GYNECOL. 123:868, 1975. 9. Murata, Y., and Martin, C. B., Jr.: Systolic time intervals of the fetal cardiac cycle, Obstet. Gynecol. 44:224, 1974. 10. Spitaels, S., Arbogast, R., Fouron, J. C., and Davignon, A.: The influence of heart rate and age on the systolic and diastolic time intervals in children, Circulation 49~1107, 1974.
Ultrasonic measurement of rate and depth of human fetal breathing: Effect of glucose S. Lee Adamson, Isaac Rapoport, London,
Ontario,
M.Sc.,* M.A.Sc.,
Alan Bock@ M.D., Alan J. Cousin, and John E. Patrick, M.D.
Ph.D.,
Canuda
A recently developed ultrasonic tracking device was used to determine the effect of maternal intravenous glucose infusion on amplitude andfrequency of breathing movements in six healthy human fetuses at 38 to 40 weeks’ gestation. Following a 2-hour observation period, an intravenous injection of either 25 gm of a 50% glucose solution or an equal volume of saline was given to the mother. Observations were continued for a further 4 hours. Fetal rib cage and abdominal diameters were measured continuously with the ultrasonic tracking device and the information was recorded on a strip chart recorder for later analysis. Breath interval and incidence measurements were highly correlated with data obtained by an independent technique (r 2 0.90). During the first 80 minutes after glucose injection, total fetal trunk movement recorded during breathing movements increased from 1.5 & 0.2 to 2.9 ? 0.4 mm (P -C 0.05). There was no significant change in the frequency or variability of fetal breathing movements after glucose infusion. (AM. J. OBSTET. GYNECOL. 147:288, 1983.)
From the Departments of Obstetrics and Gynecology and Biophysics, Medical Research Council Group in Refwoductive Biology, The University of Weston Ontario. ThU work was supported by a grant from the Canadian Medical ReAearrh Council and by a grant from the Hospital for Sick Childrm Foundation. Received for publication April i2, 1983. Accepted May 213, 1983. Reprint requests: Ms. S. Lee Adamson, Department of Biophysics, The University of Western Ontario, London, Ontario, Canada N6A 5CI. “Supported by a Canadian Medical Research Council Studentship.
The
amount
breathing plasma
glucose
maternal
injection. ever, Until
levels
plasma
consumption glucose
of time
movements
of drink,’ 3-6 The
human is
are
glucose
elevated. levels
a high-calorie or
spend when
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making maternal
is true
raised
meal,’
as a result
mechanism
fetuses
increased
as a result
intravenous
of action
whether
as a result glucose
of glucose,
is unknown. recently,
accurate
noninvasive
of of
measurements
how-
a
Volume Number
Ultrasonic
147 3
of the amplitude and frequency of human fetal breathing movements have not been possible. In 1980, Goodman” used a Doppler technique to record human fetal breathing movements automatically. He found that fetal breathing frequency was not changed by intravenous glucose administration to women who had fasted, but his technique did not allow the determination of fetal breath amplitude. In order to look for amplitude changes, an ultrasonic tracking device developed by Cousin and associates’ was used in this study to monitor continuously fetal rib cage and abdominal diameters in human fetuses near term. The two objectives of the study were to determine the effect of an intravenous injection of glucose on amplitude and frequency of fetal rib cage and abdominal movements and to compare frequency data obtained with the use of the tracking device with those collected by an observer recording breathing activity with an event marker. Method Informed consent was obtained from seven healthy pregnant women at 38 to 40 weeks’ gestation. All pregnancies had progressed normally, and the fetuses were of normal size and in good health at birth (mean 5minute Apgar score was 9.9 (range, 9 to 10). and mean birth weight was 3,530 gm (range, 2,920 to 3,950 gm). The women were studied while resting in bed in a quiet room. A longitudinal cross section of the fetus was visualized with the use of a real-time ultrasonic tracking scanner.’ Two of the scanner’s three electronic tracking channels were used to track continuously the motion of the proximal and distal fetal rib cage and abdominal wall echoes. The device produced voltages proportional to rib cage and abdominal diameters, and these were recorded on a strip chart recorder (Grass Instruments, Quincy, Massachusetts). The tracking markers could be moved to any diameter in the twodimensional fetal image and were adjusted so that one channel monitored the motion of a pair of markers situated on either side of the fetal rib cage and the other channel monitored markers located on either side of the fetal abdomen. Because image quality and viewing direction varied from fetus to fetus and from time to time, it was not always possible to track the motion of the rib cage and abdomen simultaneously. In such cases the operator aligned the tracking channels on the strongest abdominal or rib cage echoes. A visual interpretation of fetal activity was recorded on the polygraph by an observer who could not see the output of the tracking device. This person identified individual fetal breathing movements and gross fetal body movements by watching the fetal image on the video screen and coded them using an event marker on
measurement
of fetal breathing
289
Abdom.n
Fig. 1. Record of fetal activity produced by the tracking device (upper twolines) and by the observer (lower two lines). The middle line, “peaks,” was produced during analysis of the tracked record after the end of the experiment. Location of peaks in abdominal movement lfirst line) or rib cage movement (smnd line) which were identified as fetal breaths were marked by a vertical bar for subsequent determination of breath interval (see text). Observer’s event marker record of breathing (fourth line) tends to lag behind record produced by the tracking device, although the pattern of events is similar. When the “body movement” event marker is depressed by the observer (f;fth line), analysis of tracked data ceases as this indicates movement of the fetus is sufficient to obscure the ultrasonic image.
the chart record.R Gross fetal body movements were defined as fetal movements sufficient to obscure the ultrasonic image and as such were used to exclude times when motion of the tracking locations could not be ascribed to movement of a particular fetal echo. The event
marker
record
of breathing
allowed
a compari-
son of the automatic and the more standard manual techniques (Fig. 1). The subjects entered the lab at 0700 hours after fasting and abstaining from smoking for at least 8 hours. A venous catheter was inserted in the anticubital fossa, and it was maintained with a minidrip of 0.9% sodium chloride. During the study, smoking by neither subjects nor observers was permitted. At 0800 hours, data cotlection began, and at 1000 horn-s an injection of either 25 gm of glucose in aqueous solution or an equal volume of 0.9% sodium chloride (50 ml) was given intravenously to the mother ovel- 2 minutes through the venous catheter. Observations were continued for a further 4 hours. For five subjects, this experimental procedure was repeated the following day with the subject receiving the alternate injection. Two subjects were studied on 1 day only. The order of the injections was randomized, and the nature of the injection was not known to either subjects or observers. Maternal plasma glucose concentration was measured from blood samples drawn from the venous catheter and stored in tubes containing 14 mg of potassium oxaloacetate and 17.5 mg of sodium fluoride until the end of each study. Plasma was then analyzed for glucose concentration with a Beckman Glucose
290
Adamson et al.
October Am. J. Obstet.
1, 1983 Gynecol.
r =0.94
I’
A O1
I
/’
OO
I
20
%TIME
40
BREATHING:TRACKlNG
I
60
DEVICE
1.8
1.6
r =0.90
r =0.99
0B
' 1.0
I 1.2
I 1.4
1.6
I
1.8
2.0
MEAN BREATH INTERVAL(sec):TRACKlNG DEVICE I
STANDARD DEVIATION (secl:TRACKING DEVICE
Fig. 2. Plots compare data averaged over each 6 hour study period. Ordinate displays data obtained by an observer recording breathing movements with an event marker. Abscissa displays data obtained from the record produced by the tracking device. The dashed lines show the line of identity, and the correlation coefficient(r) is shown for each case. Comparison of (A) percentage of time spent breathing, (IL?]mean breath-to-breath interval during times of fetal breathing, and(C) standard deviation of breath interval obtained by the two methods. Analyzer 2 (Beckman Instruments, Fullerton, California). Analysis of tracked data. After the experiments were completed, peaks corresponding to fetal breathing movements were identified and marked with an event marker on a separate channel of the record (Fig. 1). To measure breath-to-breath interval, the marked record was replayed through the recorder’s chart drive. A photosensor, mounted above the chart paper, detected the event markers and its output was analyzed by a PDP-I 1 computer with the use of a previously
validated program.’ Because fetuses breathe episodically, i.e., periods of rhythmic breathing movements are separated by periods of apnea, an average of all breath-tobreath intervals will combine those measured within episodes with those measured between episodes. A change in breathing incidence, that is, the amount of time fetuses spend making breathing movements, will shorten intervals between episodes and will, therefore, affect this overall mean. To avoid this, intervals longer than 4 seconds were excluded from mean breath interval measurements (97% of breath intervals were less
Vohne Number
147 3
than 4 seconds). The computer program determined the time between successive photosensor outputs and calculated mean breath-to-breath interval during episodes of breathing (4-second apneic threshold) for each ZO-minute period during the study. Errors in interval determinations were estimated by measuring the variation in peak-to-peak interval determined from constant-frequency, constant-amplitude sine wave signals. The variation was assumed to be caused by the net effect of errors in the measurement technique. Variation in peak-to-peak interval was found to be minimum for high-frequency, high-amplitude signals (r0.04 second SD), and maximum for low-frequency, low-amplitude signals (50.07 second SD). Because the amplitudes and frequencies of the sine wave signals used covered the range found for human fetal breathing movements in this study, it was assumed that an error of at least 0.04 to 0.07 second was introduced by the mkasurement technique into breath interval determinations. An estimate of mean breath amplitude was obtained by measuring abdominal and rib cage diameter changes from a random sample of breaths for each 20 minute period. Although breathing movements which were recorded on only one channel were included in determinations of fetal breath interval and percentage of time spent breathing, only paradoxical movements, that is, movements recorded simultaneously but 180 degrees out of phase by both channels, were measured to estimate fetal breath amplitude. Since increased depth of fetal breathing movements may result in increased abdominal expansion, increased rib cage contraction, or both, an index of the “total movement” of the fetal trunk was obtained by summing the amplitudes of the two movements. On average, 68% of breaths recorded on one channel were recorded simultaneously but 180 degrees out of phase by the other channel (range for all chart records, 26% to 96%). This procedure effectively excluded regions of the record where tracking conditions were not optimal. Statistical analysis. Data collected in 20-minute periods were averaged to provide a mean value per breath for the 2-hour period prior to injection and for the 80-minute period following injection. Paired Student’s t tests (two tailed) were used to test for differences before and after injection for subjects receiving the same injection and unpaired Student’s t tests (two tailed) were used to test for differences between groups receiving different injections. Results are reported as the mean ? standard error of the mean for six subjects. Results Comparison of results obtained by two methods. Fig. 2 compares results obtained from the analogue output of the tracking device with results obtained
Ultrasonic
8
measurement
IO
of fetal breathing
291
12
14
TIME OF DAY (hours) Fig. 3. Effect of glucose or saline injection given at 1000 hours on maternal plasma glucose concentration. Standard error of the mean for six subjects is included in point size except at peak. from data collected by an observer using an event marker to record breathing movements. The percentage of time spent breathing dtu-ing each 6-hour study is compared in Fig. 2, A. The correlation coefficient is high, 0.94, and data points lit close to the line of identity. The percentage of time spent breathing recorded by the observer was higher in nine of 11 studies (one record produced by the observer was incomplete so has been excluded), and this difference is significant (P < 0.02, paired t test). The mean breath interval obtained by the two techniques is shown in Fig. 2, B; the correlation coefficient is 0.99, and there is no significant difference between mean breath interval obtained by the two techniques. The standard deviation of the breath interval is shown in Fig. 2, C. There is a highly significant correlation between values obtained by the two techniques (r = 0.90, P < O.OOl), but the observer recorded a significantly higher standard deviation of breath interval than was recorded by the tracking device (P < 0.001, paired t test). Results of the study. The maternal plasma glucose concentration was measured three times during the 2-hour period prior to injection. The mean value before glucose injection was 73 t 2 mg/dl. After glucose injection, maternal plasma glucose concentrations increased significantly to 183 * 5 mgidl measured 10 min. after injection (P < 0.001) and declined gradually over the next hour (Fig. 3). Sixty minutes after glucose injection, the maternal plasma glucose concentration was significantly greater than at the same time following saline injection (P < 0.005), but by 90 minutes after injection there was no significant difference. An 80-
01
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MOVEMENT (mm)
-
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ABDOMINAL
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TOTAL MOVEMENT(mm) w I
,
Volume Number
Ultrasonic
147 3
-
r
measurement
of fetal breathing
Glu
293
No’602 NS = 380
LB
Nt =I830 Ns = 859
t’db!
NG =2205 N,=2971
JM
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I 14
TIME OF DAYChours) Fig. 5. This graph shows normalized breath interval averaged over 20-minute periods, and the error bars show the standard error of the mean for six subjects. Mean breath interval during episodes of breathing is expressed as a ratio of mean breath interval obtained prior to injection for each subject. Glucose (solid line) or saline (dashed line) was injected at 1000 hours. minute period after injection, therefore, includes the time period when maternal glucose values were significantly raised (see Fig. 3). Mean amplitude of movements of the rib cage and abdomen and the “total movement” of the fetal trunk are shown in Fig. 4 for each 20-minute period. Prior to glucose injection, total movement recorded during fetal breathing was 1.5 * 0.2 mm, and this parameter increased significantly to 2.9 -+ 0.4 mm during the SO-minute period following glucose injection (P < 0.01) (Fig. 4, A). Before saline injection, total movement was 1.9 f 0.3 mm and did not change following injection. The difference between changes in total movement caused by the two treatments was significant (P < 0.05). The largest component of trunk movement during fetal breathing movements was recorded from the fetal abdomen. Mean amplitude of abdominal movements recorded before glucose injection was 0.96 t 0.08 mm, and this value increased significantly to 1.7 * 0.3 mm during the SO-minute period after injection (P < 0.02) (Fig. 4, B). Saline injection had no effect on amplitude of abdominal movements (1.2 5 0.2 to 1.2 + 0.1 mm), and the difference between amplitude changes resulting from the two treatments was significant (P < 0.05). Movements of the rib cage during fetal breathing were generally smaller and averaged 0.5 2 0.1 mm prior to glucose injection. They increased significantly to 1.1 ? 0.2 mm during the 80-minute period after glucose injection (P< 0.05) (Fig. 4, C). However, the
I
0
1
I
I
I
2
3
Breath lntervalkec)
Fig. 6. Histograms for each of the five paired studies showing the percentage of fetal breath-to-breath intervals (ordinate) recorded for each breath interval length (abscissa) during the 80-minute period after glucose injection (solid circles) and after saline injection (open tingles). Hand-drawn curves join the points. Total number of breath intervals (N) is given on the figure for each curve where NC is the number recorded in the 80-minute period after glucose and Ns is the number recorded in the same period after saline.
difference between the increase in amplitude caused by the two treatments was not significant. The mean breath-to-breath interval was normalized with the use of the mean breath interval obtained prior to injection to reduce variation caused by differences between fetuses in baseline breathing frequency. Fig. 5 shows normalized breath interval versus time. During the SO-minute period after glucose injection, breath interval decreased to 86% -C 5% of the value obtained prior to injection. Although this decrease was significant (P < 0.05), there was a small decrease in breath interval following saline injection (fell to 96% 2 4% of the value obtained before injection), and the changes in breath interval caused by the two treatments were not significantly different. Frequency distributions of breath interval length obtained during the SO-minute
294
Adamson
October Am. J. Obstet.
et al.
periods after injection paired studies. There of variation of breath line injection.
are shown in Fig. 6 for the five was no change in the coefficient interval following glucose or sa-
Comment The high correlation between data collected by the tracking device and data collected by the more standard technique of an observer using an event marker lends credence to both techniques. The observer recorded a slightly larger percentage of time spent breathing than was recorded by the tracking device. Possibly the ability of a human observer to recognize fetal breathing movements from ultrasonic echoes too weak for reliable tracking caused this discrepancy. However, the small difference between values and the high correlation means that similar data on the percentage of time spent breathing could be obtained with either method. Although no significant difference was found between mean breath interval determinations made by the two techniques, the standard deviation of breath interval recorded by the observer was higher than that recorded by the tracking device. The record of breathing activity produced by the tracking device allowed breath intervals to be measured between points of maximum rib cage or abdominal excursion. This method would be expected to yield a lower standard deviation of breath interval than data produced by the observer, who marked a breath as soon as it was recognized regardless of location in the breathing cycle. The observer may also show variations in response time. However, true standard deviation in fetal breath interval is probably still overestimated by at least 0.04 to 0.07 second as a result of error introduced during analysis of data collected by the tracking device (see Methods). Fetal breathing movements recorded by the tracking device showed increased amplitude following maternal glucose infusion. The study was double blind, so operator bias in locating the tracking markers can be ruled out. Thus, the increase in “total movement” recorded by the tracking device was caused by an increase in fetal breath amplitude. It is not known whether the amplitude change was caused by changes in neural drive to the respiratory muscles, increased muscle contractility (i.e., due to increased availability of glucose), or changes in the mechanical properties of the fetal chest and abdomen (possibly caused by the osmotic effect of glucose). Indeed, the reason why human fetal breathing movements increase in incidence following an elevation in maternal blood glucose levels also is not known. It is known that glucose is rapidly transported across the placenta$ and that glucose probably acts directly on the fetus (rather than indirectly through its action on the
1, 1983 Gynecol.
mother) because direct infusion of glucose into the circulation of fetal sheep also increases the incidence of fetal breathing activity. lo Glucose infusion to fetal sheep causes a fall in fetal arterial pH, which raises the possibility that pH may mediate the action of glucose by stimulating central chemoreceptors.” Richardson and associates’” also observed that alterations in fetal blood glucose levels were associated with changes in the proportion of time low-voltage electrocortical activity was recorded from fetuses. This suggested a change in time spent in rapid eye movement sleep. Since fetal breathing activity normally occurs exclusively during rapid eye movement sleep, Richardson and associates suggested that changes in time spent breathing could be accounted for by changes in electrocortical activity of the fetus. Fetal breath amplitude following glucose infusion has not been studied in the sheep fetus; however, the mechanisms Richardson and associates proposed to explain changes in incidence of breathing activity with glucose infusion in sheep could also account for changes in fetal breath amplitude observed in this study in the human fetus. Either stimulation of central chemoreceptors or increased general activity of the central nervous system could cause neural drive to the respiratory muscles to increase, thereby increasing breath amplitude. It is also possible that low glucose levels during fasting suppress fetal breathing activity and that glucose infusion merely removes this suppression rather than causes direct stimulation. No significant change in fetal breath interval or coefficient of variation of breath interval was observed as a result of glucose infusion. These observations are in agreement with a study by Goodman” in which a Doppler ultrasound technique was used to record human fetal breathing for analysis by computer. The absence of a change in frequency of breathing movements during episodes of breathing does not rule out a role for increased chemoreceptor activity after glucose infusion since hypercapnia in fetal sheep also causes an increase in breath amplitude without a simultaneous change in breath interval.” In conclusion, analysis of fetal rib cage and abdominal diameter changes recorded by the tracking device produced information on the percentage of time spent breathing and on breath interval which was similar to that produced by the more standard technique of an observer recording fetal breaths with an event marker. With the use of this device, a significant increase in fetal breath amplitude was found following maternal glucose infusion in human fetuses at term. The primary advantage of the use of a tracking device to record breathing activity is that, at least in double-blind studies such as this, it enables an objective assessment of changes in mean amplitude of fetal rib cage and abdominal movements to be made in the human fetus.
Volume Number
Ultrasonic
147 3
We thank Leslie Carmichael their assistance in performing
and Karen Campbell the experiments,
for and
5.
Dr. C. Botz and Livio Rigutto for their technical help. We also thank Dr. G. Tevaarwerk and Ms. Carolyn Hurst
for
performing
the
glucose
determinations.
6.
REFERENCES 1. Patrick, J., Campbell, K., Carmichael, L., Natale, R., and Richardson, B.: Patterns of human fetal breathing during the last 10 weeks of pregnancy, Obstet. Gynecol. 56:24, 1980. 2. Natale, R., Patrick, J., and Richardson, B.: Effects of human maternal venous plasma glucose concentrations on fetal breathing movements, AM. J. OBSTET. GYNECOL. 132:36. 1978. 3. Backing, A., Adamson, L., Cousin, A., Campbell, K., Carmichael, L., Natale, R., and Patrick, J.: Effects of intravenous glucose injections on human fetal breathing movements and gross fetal body movements at 38 to 40 weeks’ gestational age, AM. J. OBSTET. GYNECOL. 142:606, 1982. 4. Boddy, K., Dawes, G. S., and Robinson, J.: Intrauterine fetal breathing movements, in Gluck, L., editor: Modern
7.
8.
9.
10.
11.
measurement
of fetal breathing
Perinatal Medicine, Chicago, 1975, Year Book Medical Publishers, Inc., p. 381. Goodman, J. D. S.: The effect of intravenous glucose on human fetal breathing measured by Doppler ultrasound, Br. J. Obstet. Gynaecol. 87:1080, 1980. Natale, R., Richardson, B., and Patrick, J.: Effect of intravenous glucose infusion on human fetal breathing activity, Obstet. Gynecol. 59:320, 1981. Cousin, A. J., Rapoport, I., Campbell, K., and Patrick, J. E.: A tracking system for pulsed ultrasound images: Application to quantification of fetal breathing movements, IEEE Trans. Biomed. Eng. In press. Patrick, J., Natale, R., and Richardson, B.: Patterns of human fetal breathing activity at 34 to 35 weeks’ gestational age, AM. J. OBSTET. GYNECOL. 132:507, 1978. Zakut, H., Mashiach, S., Blankstein, J., and Serr, D. M.: Maternal and fetal response to rapid glucose loading in pregnancy and labour, Isr. J. Med. Sci. 11:632, 1975. Richardson, B., Hohimer, A. R., Mueggler, P., and Bissonnette, J.: Effects of glucose concentration on fetal breathing movements and electrocortical activity in fetal lambs, AM. J. OBSTET. GYNECOL. 142:678, 1982. Chapman, R. L. K., Dawes, G. S., Rurak, D. W., and Wilds, P. L.: Breathing movements in fetal lambs and the effect of hypercapnia, J. Physiol. (Lond.) 302:19, 1980.
The impact of publicly funded perinatal care programs on neonatal outcome, Georgia, 1976- 1978 Alison M. Spitz, M.P.H., George L. Rubin, M.B., F.R.A.C.P., James Marks, M.D., Anthony H. Burton, B.S., and Elizabeth Atlanta,
Brian J. McCarthy, Berrier, M.P.A.
M.D.,
Georgia
The State of Georgia administers three publicly funded perinatal care programs for medically high risk and/or low-income women: the High Risk Pregnancy Program, the Medicaid Program, and the Maternal and Infant Care Projects. To assess the impact of these programs on infant health, we compared the birth weight distribution and neonatal mortality rates of infants born to women in each program with those of infants of a nonfunded group of women with ~12 years’ education. Infants of women in publicly funded groups were more likely to weigh 52,500gm at birth than those of women in the nonfunded group. Neonatal mortality rates for publicly funded groups were similar to those of the nonfunded group. The neonatal mortality rates for infants of birth weight 52,500 gm of publicly-funded women were significantly lower than those of the nonfunded women. There were no significant differences between groups for neonatal mortality rates for infants of birth weight >2,500 gm. These findings suggest that publicly funded perinatal care programs may improve neonatal survival of infants of birth weight ~2,500 gm of low-income mothers. (AM. J. OBSTET. GYNECOL. 147:295, 1983.)
The 1976 neonatal mortality rate for Georgia was 10.9 per 1,000 live births. The State of Georgia, From the Division ofReproductive Health, Center-for Health Promotion and Education, Centers for Disease Control, Public Health Seruice, United States Department of Health and Human Services, and the Family Health Services Section, Division of Public Health, Georgia Department of Human Resources. Received for @blication March 15, 1983. Revised May 13, 1983. Accepted May 20, 1983. Reprint requests: Alison M. Spitz, United States Department $ Health and Human Services, Public Health Seroice, Centers for Disease Control, Center for Health Promotion and Education, Division of Reproductive Health, Atlanta, Georgia 30333.
through the Department of Human Resources, administers three perinatal care programs to reduce neonatal deaths in infants of medically high-risk and/or lowincome women. These programs are the High Risk Pregnancy Program, the Medicaid Program, and the Maternal and Infant Care Projects. To date, the effect of these publicly funded programs on neonatal outcome has not been evaluated. In this study, we addressed the following questions: (1) What is the birth weight distribution of infants of women publicly funded for perinatal care compared to that for infants of women with <12 years’ education 295
mother occur
et al.
but also by the in the postoperative
In conclusion, of postoperative chronic enough
October 1, 1983 Am. J. Obstet. Gynecol.
this
metabolic imbalances period.“, 7
study
showed
recuperation
are
maternal-fetal for interpretation
that
known
at least
necessary
animal preparation of data on fetal
before
to
3 days the
is stable myocardial
function. We are grateful for the technical assistance provided by Mrs. Janie Prosmane, Marie-ThCrPse Rabeau, and Marguerite P.-M&g&las and for the cooperation of Ms. M. Raymond in typing the manuscript. REFERENCES 1. Evers, J. L. H.: Cardiac pre-ejection period during prenatal life, Gynecol. Obstet. Invest. 11:193, 1980. 2. Organ, L. G., Milligan, J. E., Goodwin, J. W., and Bain, M. 1. C.: The pre-eiection period of the fetal heart: Response to stress in ;he term fetal lamb, AM. J. OBSTET. GYNECOL. 115:377, 1973. 3. Murata, Y., Miyake, K., and Quiligan, E. J.: Pre-ejection period of cardiac cycles in fetal lamb, AM. J. OBSTET. GYNECOL. 133:509. 1979.
4. Murata, Y., Martin, C. B., Jr., Ikenoue, T., and Petrie, R. H.: Cardiac systolic time intervals in fetal monkeys: Ventricular ejection time, AM. J. OBSTET. GYNECOL. 136: 603, 1980. 5. Murata, Y., Martin, C. B., Jr., Ikenoue, T., and Petrie, R. H.: Cardiac systolic time intervals in fetal monkeys: Pre-ejection period, AM. J. OBSTET. GYNECOL. 132:285, 1978. 6. Clapp, J. F., III, Abrams, R. M., and Patel, N.: Fetal metabolism during recovery from surgical stress, Gynecol. Invest. 8:299, 1977. 7. Gresham, E. L., Rankin, J. H. G., Makowski, E. L., Meschia, G., and Battaglia, F. C.: An evaluation of fetal renal function in a chronic sheep preparation, J. Clin. Invest. 51:149, 1972. J. C., Korcaz, Y., and Leduc, B.: Cardiovascular 8. Fouron, changes associated with fetal breathing, AM. J. OBSTET. GYNECOL. 123:868, 1975. 9. Murata, Y., and Martin, C. B., Jr.: Systolic time intervals of the fetal cardiac cycle, Obstet. Gynecol. 44:224, 1974. 10. Spitaels, S., Arbogast, R., Fouron, J. C., and Davignon, A.: The influence of heart rate and age on the systolic and diastolic time intervals in children, Circulation 49~1107, 1974.
Ultrasonic measurement of rate and depth of human fetal breathing: Effect of glucose S. Lee Adamson, Isaac Rapoport, London,
Ontario,
M.Sc.,* M.A.Sc.,
Alan Bock@ M.D., Alan J. Cousin, and John E. Patrick, M.D.
Ph.D.,
Canuda
A recently developed ultrasonic tracking device was used to determine the effect of maternal intravenous glucose infusion on amplitude andfrequency of breathing movements in six healthy human fetuses at 38 to 40 weeks’ gestation. Following a 2-hour observation period, an intravenous injection of either 25 gm of a 50% glucose solution or an equal volume of saline was given to the mother. Observations were continued for a further 4 hours. Fetal rib cage and abdominal diameters were measured continuously with the ultrasonic tracking device and the information was recorded on a strip chart recorder for later analysis. Breath interval and incidence measurements were highly correlated with data obtained by an independent technique (r 2 0.90). During the first 80 minutes after glucose injection, total fetal trunk movement recorded during breathing movements increased from 1.5 & 0.2 to 2.9 ? 0.4 mm (P -C 0.05). There was no significant change in the frequency or variability of fetal breathing movements after glucose infusion. (AM. J. OBSTET. GYNECOL. 147:288, 1983.)
From the Departments of Obstetrics and Gynecology and Biophysics, Medical Research Council Group in Refwoductive Biology, The University of Weston Ontario. ThU work was supported by a grant from the Canadian Medical ReAearrh Council and by a grant from the Hospital for Sick Childrm Foundation. Received for publication April i2, 1983. Accepted May 213, 1983. Reprint requests: Ms. S. Lee Adamson, Department of Biophysics, The University of Western Ontario, London, Ontario, Canada N6A 5CI. “Supported by a Canadian Medical Research Council Studentship.
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how-
a
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of the amplitude and frequency of human fetal breathing movements have not been possible. In 1980, Goodman” used a Doppler technique to record human fetal breathing movements automatically. He found that fetal breathing frequency was not changed by intravenous glucose administration to women who had fasted, but his technique did not allow the determination of fetal breath amplitude. In order to look for amplitude changes, an ultrasonic tracking device developed by Cousin and associates’ was used in this study to monitor continuously fetal rib cage and abdominal diameters in human fetuses near term. The two objectives of the study were to determine the effect of an intravenous injection of glucose on amplitude and frequency of fetal rib cage and abdominal movements and to compare frequency data obtained with the use of the tracking device with those collected by an observer recording breathing activity with an event marker. Method Informed consent was obtained from seven healthy pregnant women at 38 to 40 weeks’ gestation. All pregnancies had progressed normally, and the fetuses were of normal size and in good health at birth (mean 5minute Apgar score was 9.9 (range, 9 to 10). and mean birth weight was 3,530 gm (range, 2,920 to 3,950 gm). The women were studied while resting in bed in a quiet room. A longitudinal cross section of the fetus was visualized with the use of a real-time ultrasonic tracking scanner.’ Two of the scanner’s three electronic tracking channels were used to track continuously the motion of the proximal and distal fetal rib cage and abdominal wall echoes. The device produced voltages proportional to rib cage and abdominal diameters, and these were recorded on a strip chart recorder (Grass Instruments, Quincy, Massachusetts). The tracking markers could be moved to any diameter in the twodimensional fetal image and were adjusted so that one channel monitored the motion of a pair of markers situated on either side of the fetal rib cage and the other channel monitored markers located on either side of the fetal abdomen. Because image quality and viewing direction varied from fetus to fetus and from time to time, it was not always possible to track the motion of the rib cage and abdomen simultaneously. In such cases the operator aligned the tracking channels on the strongest abdominal or rib cage echoes. A visual interpretation of fetal activity was recorded on the polygraph by an observer who could not see the output of the tracking device. This person identified individual fetal breathing movements and gross fetal body movements by watching the fetal image on the video screen and coded them using an event marker on
measurement
of fetal breathing
289
Abdom.n
Fig. 1. Record of fetal activity produced by the tracking device (upper twolines) and by the observer (lower two lines). The middle line, “peaks,” was produced during analysis of the tracked record after the end of the experiment. Location of peaks in abdominal movement lfirst line) or rib cage movement (smnd line) which were identified as fetal breaths were marked by a vertical bar for subsequent determination of breath interval (see text). Observer’s event marker record of breathing (fourth line) tends to lag behind record produced by the tracking device, although the pattern of events is similar. When the “body movement” event marker is depressed by the observer (f;fth line), analysis of tracked data ceases as this indicates movement of the fetus is sufficient to obscure the ultrasonic image.
the chart record.R Gross fetal body movements were defined as fetal movements sufficient to obscure the ultrasonic image and as such were used to exclude times when motion of the tracking locations could not be ascribed to movement of a particular fetal echo. The event
marker
record
of breathing
allowed
a compari-
son of the automatic and the more standard manual techniques (Fig. 1). The subjects entered the lab at 0700 hours after fasting and abstaining from smoking for at least 8 hours. A venous catheter was inserted in the anticubital fossa, and it was maintained with a minidrip of 0.9% sodium chloride. During the study, smoking by neither subjects nor observers was permitted. At 0800 hours, data cotlection began, and at 1000 horn-s an injection of either 25 gm of glucose in aqueous solution or an equal volume of 0.9% sodium chloride (50 ml) was given intravenously to the mother ovel- 2 minutes through the venous catheter. Observations were continued for a further 4 hours. For five subjects, this experimental procedure was repeated the following day with the subject receiving the alternate injection. Two subjects were studied on 1 day only. The order of the injections was randomized, and the nature of the injection was not known to either subjects or observers. Maternal plasma glucose concentration was measured from blood samples drawn from the venous catheter and stored in tubes containing 14 mg of potassium oxaloacetate and 17.5 mg of sodium fluoride until the end of each study. Plasma was then analyzed for glucose concentration with a Beckman Glucose
290
Adamson et al.
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1, 1983 Gynecol.
r =0.94
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STANDARD DEVIATION (secl:TRACKING DEVICE
Fig. 2. Plots compare data averaged over each 6 hour study period. Ordinate displays data obtained by an observer recording breathing movements with an event marker. Abscissa displays data obtained from the record produced by the tracking device. The dashed lines show the line of identity, and the correlation coefficient(r) is shown for each case. Comparison of (A) percentage of time spent breathing, (IL?]mean breath-to-breath interval during times of fetal breathing, and(C) standard deviation of breath interval obtained by the two methods. Analyzer 2 (Beckman Instruments, Fullerton, California). Analysis of tracked data. After the experiments were completed, peaks corresponding to fetal breathing movements were identified and marked with an event marker on a separate channel of the record (Fig. 1). To measure breath-to-breath interval, the marked record was replayed through the recorder’s chart drive. A photosensor, mounted above the chart paper, detected the event markers and its output was analyzed by a PDP-I 1 computer with the use of a previously
validated program.’ Because fetuses breathe episodically, i.e., periods of rhythmic breathing movements are separated by periods of apnea, an average of all breath-tobreath intervals will combine those measured within episodes with those measured between episodes. A change in breathing incidence, that is, the amount of time fetuses spend making breathing movements, will shorten intervals between episodes and will, therefore, affect this overall mean. To avoid this, intervals longer than 4 seconds were excluded from mean breath interval measurements (97% of breath intervals were less
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than 4 seconds). The computer program determined the time between successive photosensor outputs and calculated mean breath-to-breath interval during episodes of breathing (4-second apneic threshold) for each ZO-minute period during the study. Errors in interval determinations were estimated by measuring the variation in peak-to-peak interval determined from constant-frequency, constant-amplitude sine wave signals. The variation was assumed to be caused by the net effect of errors in the measurement technique. Variation in peak-to-peak interval was found to be minimum for high-frequency, high-amplitude signals (r0.04 second SD), and maximum for low-frequency, low-amplitude signals (50.07 second SD). Because the amplitudes and frequencies of the sine wave signals used covered the range found for human fetal breathing movements in this study, it was assumed that an error of at least 0.04 to 0.07 second was introduced by the mkasurement technique into breath interval determinations. An estimate of mean breath amplitude was obtained by measuring abdominal and rib cage diameter changes from a random sample of breaths for each 20 minute period. Although breathing movements which were recorded on only one channel were included in determinations of fetal breath interval and percentage of time spent breathing, only paradoxical movements, that is, movements recorded simultaneously but 180 degrees out of phase by both channels, were measured to estimate fetal breath amplitude. Since increased depth of fetal breathing movements may result in increased abdominal expansion, increased rib cage contraction, or both, an index of the “total movement” of the fetal trunk was obtained by summing the amplitudes of the two movements. On average, 68% of breaths recorded on one channel were recorded simultaneously but 180 degrees out of phase by the other channel (range for all chart records, 26% to 96%). This procedure effectively excluded regions of the record where tracking conditions were not optimal. Statistical analysis. Data collected in 20-minute periods were averaged to provide a mean value per breath for the 2-hour period prior to injection and for the 80-minute period following injection. Paired Student’s t tests (two tailed) were used to test for differences before and after injection for subjects receiving the same injection and unpaired Student’s t tests (two tailed) were used to test for differences between groups receiving different injections. Results are reported as the mean ? standard error of the mean for six subjects. Results Comparison of results obtained by two methods. Fig. 2 compares results obtained from the analogue output of the tracking device with results obtained
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IO
of fetal breathing
291
12
14
TIME OF DAY (hours) Fig. 3. Effect of glucose or saline injection given at 1000 hours on maternal plasma glucose concentration. Standard error of the mean for six subjects is included in point size except at peak. from data collected by an observer using an event marker to record breathing movements. The percentage of time spent breathing dtu-ing each 6-hour study is compared in Fig. 2, A. The correlation coefficient is high, 0.94, and data points lit close to the line of identity. The percentage of time spent breathing recorded by the observer was higher in nine of 11 studies (one record produced by the observer was incomplete so has been excluded), and this difference is significant (P < 0.02, paired t test). The mean breath interval obtained by the two techniques is shown in Fig. 2, B; the correlation coefficient is 0.99, and there is no significant difference between mean breath interval obtained by the two techniques. The standard deviation of the breath interval is shown in Fig. 2, C. There is a highly significant correlation between values obtained by the two techniques (r = 0.90, P < O.OOl), but the observer recorded a significantly higher standard deviation of breath interval than was recorded by the tracking device (P < 0.001, paired t test). Results of the study. The maternal plasma glucose concentration was measured three times during the 2-hour period prior to injection. The mean value before glucose injection was 73 t 2 mg/dl. After glucose injection, maternal plasma glucose concentrations increased significantly to 183 * 5 mgidl measured 10 min. after injection (P < 0.001) and declined gradually over the next hour (Fig. 3). Sixty minutes after glucose injection, the maternal plasma glucose concentration was significantly greater than at the same time following saline injection (P < 0.005), but by 90 minutes after injection there was no significant difference. An 80-
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measurement
of fetal breathing
Glu
293
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NG =2205 N,=2971
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TIME OF DAYChours) Fig. 5. This graph shows normalized breath interval averaged over 20-minute periods, and the error bars show the standard error of the mean for six subjects. Mean breath interval during episodes of breathing is expressed as a ratio of mean breath interval obtained prior to injection for each subject. Glucose (solid line) or saline (dashed line) was injected at 1000 hours. minute period after injection, therefore, includes the time period when maternal glucose values were significantly raised (see Fig. 3). Mean amplitude of movements of the rib cage and abdomen and the “total movement” of the fetal trunk are shown in Fig. 4 for each 20-minute period. Prior to glucose injection, total movement recorded during fetal breathing was 1.5 * 0.2 mm, and this parameter increased significantly to 2.9 -+ 0.4 mm during the SO-minute period following glucose injection (P < 0.01) (Fig. 4, A). Before saline injection, total movement was 1.9 f 0.3 mm and did not change following injection. The difference between changes in total movement caused by the two treatments was significant (P < 0.05). The largest component of trunk movement during fetal breathing movements was recorded from the fetal abdomen. Mean amplitude of abdominal movements recorded before glucose injection was 0.96 t 0.08 mm, and this value increased significantly to 1.7 * 0.3 mm during the SO-minute period after injection (P < 0.02) (Fig. 4, B). Saline injection had no effect on amplitude of abdominal movements (1.2 5 0.2 to 1.2 + 0.1 mm), and the difference between amplitude changes resulting from the two treatments was significant (P < 0.05). Movements of the rib cage during fetal breathing were generally smaller and averaged 0.5 2 0.1 mm prior to glucose injection. They increased significantly to 1.1 ? 0.2 mm during the 80-minute period after glucose injection (P< 0.05) (Fig. 4, C). However, the
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2
3
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Fig. 6. Histograms for each of the five paired studies showing the percentage of fetal breath-to-breath intervals (ordinate) recorded for each breath interval length (abscissa) during the 80-minute period after glucose injection (solid circles) and after saline injection (open tingles). Hand-drawn curves join the points. Total number of breath intervals (N) is given on the figure for each curve where NC is the number recorded in the 80-minute period after glucose and Ns is the number recorded in the same period after saline.
difference between the increase in amplitude caused by the two treatments was not significant. The mean breath-to-breath interval was normalized with the use of the mean breath interval obtained prior to injection to reduce variation caused by differences between fetuses in baseline breathing frequency. Fig. 5 shows normalized breath interval versus time. During the SO-minute period after glucose injection, breath interval decreased to 86% -C 5% of the value obtained prior to injection. Although this decrease was significant (P < 0.05), there was a small decrease in breath interval following saline injection (fell to 96% 2 4% of the value obtained before injection), and the changes in breath interval caused by the two treatments were not significantly different. Frequency distributions of breath interval length obtained during the SO-minute
294
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October Am. J. Obstet.
et al.
periods after injection paired studies. There of variation of breath line injection.
are shown in Fig. 6 for the five was no change in the coefficient interval following glucose or sa-
Comment The high correlation between data collected by the tracking device and data collected by the more standard technique of an observer using an event marker lends credence to both techniques. The observer recorded a slightly larger percentage of time spent breathing than was recorded by the tracking device. Possibly the ability of a human observer to recognize fetal breathing movements from ultrasonic echoes too weak for reliable tracking caused this discrepancy. However, the small difference between values and the high correlation means that similar data on the percentage of time spent breathing could be obtained with either method. Although no significant difference was found between mean breath interval determinations made by the two techniques, the standard deviation of breath interval recorded by the observer was higher than that recorded by the tracking device. The record of breathing activity produced by the tracking device allowed breath intervals to be measured between points of maximum rib cage or abdominal excursion. This method would be expected to yield a lower standard deviation of breath interval than data produced by the observer, who marked a breath as soon as it was recognized regardless of location in the breathing cycle. The observer may also show variations in response time. However, true standard deviation in fetal breath interval is probably still overestimated by at least 0.04 to 0.07 second as a result of error introduced during analysis of data collected by the tracking device (see Methods). Fetal breathing movements recorded by the tracking device showed increased amplitude following maternal glucose infusion. The study was double blind, so operator bias in locating the tracking markers can be ruled out. Thus, the increase in “total movement” recorded by the tracking device was caused by an increase in fetal breath amplitude. It is not known whether the amplitude change was caused by changes in neural drive to the respiratory muscles, increased muscle contractility (i.e., due to increased availability of glucose), or changes in the mechanical properties of the fetal chest and abdomen (possibly caused by the osmotic effect of glucose). Indeed, the reason why human fetal breathing movements increase in incidence following an elevation in maternal blood glucose levels also is not known. It is known that glucose is rapidly transported across the placenta$ and that glucose probably acts directly on the fetus (rather than indirectly through its action on the
1, 1983 Gynecol.
mother) because direct infusion of glucose into the circulation of fetal sheep also increases the incidence of fetal breathing activity. lo Glucose infusion to fetal sheep causes a fall in fetal arterial pH, which raises the possibility that pH may mediate the action of glucose by stimulating central chemoreceptors.” Richardson and associates’” also observed that alterations in fetal blood glucose levels were associated with changes in the proportion of time low-voltage electrocortical activity was recorded from fetuses. This suggested a change in time spent in rapid eye movement sleep. Since fetal breathing activity normally occurs exclusively during rapid eye movement sleep, Richardson and associates suggested that changes in time spent breathing could be accounted for by changes in electrocortical activity of the fetus. Fetal breath amplitude following glucose infusion has not been studied in the sheep fetus; however, the mechanisms Richardson and associates proposed to explain changes in incidence of breathing activity with glucose infusion in sheep could also account for changes in fetal breath amplitude observed in this study in the human fetus. Either stimulation of central chemoreceptors or increased general activity of the central nervous system could cause neural drive to the respiratory muscles to increase, thereby increasing breath amplitude. It is also possible that low glucose levels during fasting suppress fetal breathing activity and that glucose infusion merely removes this suppression rather than causes direct stimulation. No significant change in fetal breath interval or coefficient of variation of breath interval was observed as a result of glucose infusion. These observations are in agreement with a study by Goodman” in which a Doppler ultrasound technique was used to record human fetal breathing for analysis by computer. The absence of a change in frequency of breathing movements during episodes of breathing does not rule out a role for increased chemoreceptor activity after glucose infusion since hypercapnia in fetal sheep also causes an increase in breath amplitude without a simultaneous change in breath interval.” In conclusion, analysis of fetal rib cage and abdominal diameter changes recorded by the tracking device produced information on the percentage of time spent breathing and on breath interval which was similar to that produced by the more standard technique of an observer recording fetal breaths with an event marker. With the use of this device, a significant increase in fetal breath amplitude was found following maternal glucose infusion in human fetuses at term. The primary advantage of the use of a tracking device to record breathing activity is that, at least in double-blind studies such as this, it enables an objective assessment of changes in mean amplitude of fetal rib cage and abdominal movements to be made in the human fetus.
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We thank Leslie Carmichael their assistance in performing
and Karen Campbell the experiments,
for and
5.
Dr. C. Botz and Livio Rigutto for their technical help. We also thank Dr. G. Tevaarwerk and Ms. Carolyn Hurst
for
performing
the
glucose
determinations.
6.
REFERENCES 1. Patrick, J., Campbell, K., Carmichael, L., Natale, R., and Richardson, B.: Patterns of human fetal breathing during the last 10 weeks of pregnancy, Obstet. Gynecol. 56:24, 1980. 2. Natale, R., Patrick, J., and Richardson, B.: Effects of human maternal venous plasma glucose concentrations on fetal breathing movements, AM. J. OBSTET. GYNECOL. 132:36. 1978. 3. Backing, A., Adamson, L., Cousin, A., Campbell, K., Carmichael, L., Natale, R., and Patrick, J.: Effects of intravenous glucose injections on human fetal breathing movements and gross fetal body movements at 38 to 40 weeks’ gestational age, AM. J. OBSTET. GYNECOL. 142:606, 1982. 4. Boddy, K., Dawes, G. S., and Robinson, J.: Intrauterine fetal breathing movements, in Gluck, L., editor: Modern
7.
8.
9.
10.
11.
measurement
of fetal breathing
Perinatal Medicine, Chicago, 1975, Year Book Medical Publishers, Inc., p. 381. Goodman, J. D. S.: The effect of intravenous glucose on human fetal breathing measured by Doppler ultrasound, Br. J. Obstet. Gynaecol. 87:1080, 1980. Natale, R., Richardson, B., and Patrick, J.: Effect of intravenous glucose infusion on human fetal breathing activity, Obstet. Gynecol. 59:320, 1981. Cousin, A. J., Rapoport, I., Campbell, K., and Patrick, J. E.: A tracking system for pulsed ultrasound images: Application to quantification of fetal breathing movements, IEEE Trans. Biomed. Eng. In press. Patrick, J., Natale, R., and Richardson, B.: Patterns of human fetal breathing activity at 34 to 35 weeks’ gestational age, AM. J. OBSTET. GYNECOL. 132:507, 1978. Zakut, H., Mashiach, S., Blankstein, J., and Serr, D. M.: Maternal and fetal response to rapid glucose loading in pregnancy and labour, Isr. J. Med. Sci. 11:632, 1975. Richardson, B., Hohimer, A. R., Mueggler, P., and Bissonnette, J.: Effects of glucose concentration on fetal breathing movements and electrocortical activity in fetal lambs, AM. J. OBSTET. GYNECOL. 142:678, 1982. Chapman, R. L. K., Dawes, G. S., Rurak, D. W., and Wilds, P. L.: Breathing movements in fetal lambs and the effect of hypercapnia, J. Physiol. (Lond.) 302:19, 1980.
The impact of publicly funded perinatal care programs on neonatal outcome, Georgia, 1976- 1978 Alison M. Spitz, M.P.H., George L. Rubin, M.B., F.R.A.C.P., James Marks, M.D., Anthony H. Burton, B.S., and Elizabeth Atlanta,
Brian J. McCarthy, Berrier, M.P.A.
M.D.,
Georgia
The State of Georgia administers three publicly funded perinatal care programs for medically high risk and/or low-income women: the High Risk Pregnancy Program, the Medicaid Program, and the Maternal and Infant Care Projects. To assess the impact of these programs on infant health, we compared the birth weight distribution and neonatal mortality rates of infants born to women in each program with those of infants of a nonfunded group of women with ~12 years’ education. Infants of women in publicly funded groups were more likely to weigh 52,500gm at birth than those of women in the nonfunded group. Neonatal mortality rates for publicly funded groups were similar to those of the nonfunded group. The neonatal mortality rates for infants of birth weight 52,500 gm of publicly-funded women were significantly lower than those of the nonfunded women. There were no significant differences between groups for neonatal mortality rates for infants of birth weight >2,500 gm. These findings suggest that publicly funded perinatal care programs may improve neonatal survival of infants of birth weight ~2,500 gm of low-income mothers. (AM. J. OBSTET. GYNECOL. 147:295, 1983.)
The 1976 neonatal mortality rate for Georgia was 10.9 per 1,000 live births. The State of Georgia, From the Division ofReproductive Health, Center-for Health Promotion and Education, Centers for Disease Control, Public Health Seruice, United States Department of Health and Human Services, and the Family Health Services Section, Division of Public Health, Georgia Department of Human Resources. Received for @blication March 15, 1983. Revised May 13, 1983. Accepted May 20, 1983. Reprint requests: Alison M. Spitz, United States Department $ Health and Human Services, Public Health Seroice, Centers for Disease Control, Center for Health Promotion and Education, Division of Reproductive Health, Atlanta, Georgia 30333.
through the Department of Human Resources, administers three perinatal care programs to reduce neonatal deaths in infants of medically high-risk and/or lowincome women. These programs are the High Risk Pregnancy Program, the Medicaid Program, and the Maternal and Infant Care Projects. To date, the effect of these publicly funded programs on neonatal outcome has not been evaluated. In this study, we addressed the following questions: (1) What is the birth weight distribution of infants of women publicly funded for perinatal care compared to that for infants of women with <12 years’ education 295