Changes in human placental oxygenation during maternal hyperoxia estimated by blood oxygen level-dependent magnetic resonance imaging (BOLD MRI).

OBJECTIVES: To investigate changes in human placental oxygenation during maternal hyperoxia using non-invasive blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI). METHODS: Eight healthy pregnant women with uncomplicated singleton pregnancies at gestational weeks 28-36 were examined with BOLD MRI, over two consecutive 5-min periods of different oxygenation: first normoxia (21% O2 ) and then hyperoxia (12 L O2 /min), achieved by controlling the maternal oxygen supply with a non-rebreather facial mask. Selecting three slices showing cross-sections of the central part of the placenta, we investigated total placental oxygenation by drawing regions of interest (ROIs) covering the entire placenta, and regional placental oxygenation by drawing smaller ROIs in the darker and brighter areas of the placenta. For each ROI, the difference in BOLD signal between the two episodes was determined and the percentage increase in BOLD signal during hyperoxia (ΔBOLD) was calculated. RESULTS: In the BOLD image, the normoxic placenta appeared heterogeneous, with darker areas located to the fetal side and brighter areas to the maternal side. During hyperoxia, the placenta became brighter and the structure more homogeneous, and the BOLD signal of the total placenta increased (ΔBOLDtot , 15.2 ± 3.2% (mean ± SD), P < 0.0001). The increase was seen predominantly in the dark areas in the fetal part of the placenta (ΔBOLDfet , 32.1 ± 9.3%) compared with in the bright areas in the maternal part of the placenta (ΔBOLDmat , 5.4 ± 3.5%). CONCLUSION: During hyperoxia, placental oxygenation was increased predominantly in the darker placental areas, which, given their anatomical location, represent the fetal circulation of the placenta. To our knowledge, this is the first study to successfully visualize changes in placental oxygenation using BOLD MRI.

Late termination of pregnancy: a comparison of obstetricians' experience in eight European countries.

OBJECTIVE: To compare the experience and attitude of obstetricians in Europe towards late termination of pregnancy and the factors affecting their responses. DESIGN: Cluster sampling cross-sectional survey. All neonatal intensive care unit (NICU)-associated maternity units were recruited (census sampling) in Luxembourg, the Netherlands and Sweden. In France, Germany, Italy, Spain and the UK, units were selected at random. In every recruited unit, all obstetricians with at least 6 months' experience were invited to participate. SETTING: NICU-associated maternity units in eight European countries. POPULATION: Obstetricians with at least 6 months' clinical experience. METHODS: An anonymous, self-administered questionnaire was used. Multinomial logistic analysis was used to identify factors predicting the obstetricians' views about modifying the law governing late termination in their country. MAIN OUTCOME MEASURE: Obstetricians' experience of late termination of pregnancy and views about national policies. RESULTS: One hundred and five units and 1530 obstetricians participated (response rates 70 and 77% respectively). The most common indications for late termination were congenital anomalies and women's physical health. Feticide was not common except in France, Luxembourg and the UK. Active euthanasia of a liveborn was practiced in France and the Netherlands. Obstetricians in Germany were more likely to feel that late termination should be more severely restricted, the opposite was true in Spain and the Netherlands. In Italy, there was dissatisfaction with current status, but opinion was divided, reflecting views on both sides of the debate. CONCLUSIONS: This research outlines current practice in a difficult and sensitive area and suggests the need for more discussion and support for all those who were involved.

Mucopolysaccharidosis VII as cause of fetal hydrops in early pregnancy.

We report on fetal hydrops presenting at 18 weeks of gestation and diagnosed as beta-glucuronidase deficiency. The parents were first cousins and there were 2 previous similar fetal deaths. beta-Glucuronidase was absent in cultured fetal fibroblasts and lymphoblasts but was normal in the tested relatives. The activities of other lysosomal enzymes were normal.

Fetal blood flow in pregnancies complicated by intrauterine growth retardation.

A noninvasive pulsed Doppler ultrasound technique was used to characterize blood flow in the descending thoracic aorta and the intra-abdominal part of the umbilical vein in 159 fetuses suspected of intrauterine growth retardation (IUGR) on the basis of ultrasound fetometry. From this group, 74 infants with IUGR (defined as gestational age-related birth weight of 2 standard deviations [SD] or more below the population mean) were born. The blood flow results were not available to the clinicians managing the pregnancies. Blood flow mean velocity in the fetal aorta was lower, pulsatility index and rising slope higher, and umbilical volume flow and umbilical flow per 100 g placental tissue were lower in the pregnancies with IUGR than in 21 normal pregnancies. The waveform of the maximum aortic velocity envelope was related to operative delivery for fetal distress, Apgar score, and umbilical cord blood pH. The pulsatility index and the configurational assessment of the diastolic part of the waveform were combined to form a new concept, the blood flow class. The blood flow class was abnormal in 57% of the fetuses classified as having IUGR at birth and in 93% of those growth-retarded fetuses who subsequently developed signs of fetal distress requiring operative delivery. Waveform analysis, in terms of blood flow class, seems to be a useful tool in the surveillance of fetuses when IUGR is suspected. Abnormal blood flow class is a marker of fetal distress and probably gives an earlier indication than antenatal nonstressed cardiotocography. The results of this study point to a strong association between IUGR and impaired fetal blood flow. The aortic volume blood flow, unlike waveform analysis, does not seem to be a variable sensitive enough to predict fetal outcome in the individual pregnancy.

Fetal cardiac arrhythmias: Doppler assessment.

Pregnancies in which fetal cardiac arrhythmias are present are associated with an elevated perinatal and neonatal mortality. In this group various major and minor fetal malformations, including heart malformations, are more common. FECG and phonocardiogram give some information on the type of arrhythmia in favorable cases. Real-time imaging detects fetal heart malformations and late signs of heart failure. Fetal echocardiogram is of great aid for the classification of the arrhythmia and for the detection of heart malformations. By applying combined real-time linear array and pulsed Doppler technique in cases of fetal cardiac arrhythmia, important information on the fetal circulatory state can be obtained. Estimations of the volume blood flow guide the clinician in the practical handling of these cases. Volume blood-flow estimations can probably detect imminent fetal heart failure. Therapeutic effects can be followed, and the timing of delivery can be optimized taking the circulatory state into account. Within the fetal heart rate range 50 to 250 beats/min adequate blood circulation is usually maintained in the fetus. The peak velocity, the acceleration, and the rising slope are all increased in the postextrasystolic beat, indicating the existence of postextrasystolic potentiation in the fetal heart. These three parameters can be related to the ventricular filling time, supporting the opinion that the fetal heart follows the rules of the Frank Starling relationship. Fetal arrhythmias constitute also an experimental model for the study of fetal cardiac physiology.

Blood flow in the fetal descending aorta.

Doppler estimation of the blood flow in the descending aorta of the fetus and waveform analysis of the maximum aortic velocity provide valuable information on fetal circulation. When estimating fetal aortic flow, it is important to consider possible sources of error; even when recording the maximum aortic velocity for waveform analysis, to obtain reproducible results it is important to use a low high-pass filter, a well-defined angle of insonation, and a standardized site of measurement and to avoid periods of fetal breathing and activity. In normal pregnancy the time-averaged mean velocity in the descending aorta is stable throughout the third trimester. The weight-related flow is stable until 37 weeks, after which it falls slightly. The placental proportion of the flow in the thoracic descending aorta decreases toward term. In the aorta of normal fetuses there is positive flow throughout the whole heart cycle, which is due to the low vascular resistance in the placental circulation. The waveform of the aortic velocity can be characterized by the PI, which is stable during the last trimester of gestation. Caution is required when interpreting changes in the aortic PI, as it is not only affected by the peripheral resistance but also by the heart performance. Furthermore, PI is related to fetal heart rate. Near term different values of PI are found in different fetal behavioral states. In fetuses with retarded growth and in fetuses at distress, characteristic changes of the aortic velocity waveform have been reported by several researchers: the end-diastolic velocity diminishes and disappears, and in extreme cases a brief reversal of flow in diastole was observed. Consequently, the PI increases in such cases. The absence of the end-diastolic aortic velocity can easily be determined and is the best indicator of fetal status: in fetuses with absent end-diastolic velocity the incidence of perinatal mortality and morbidity is significantly higher than in fetuses with positive flow throughout the cycle. In pregnancies with hypertension or diabetes mellitus, normal aortic flow has been reported, as long as the fetuses were not growth retarded. In cases of severe Rh-isoimmunization, the mean aortic velocity correlates with fetal hematocrit. In hypoxic fetuses the mean velocity was reported to correlate with the degree of hypoxia, hypercarbia, and acidosis.(ABSTRACT TRUNCATED AT 400 WORDS)

Blood flow in the fetal descending aorta; intrinsic factors affecting fetal blood flow, i.e. fetal breathing movements and cardiac arrhythmia.

An ultrasonic method combining real-time ultrasonography and pulsed Doppler technique was used for the examination of blood flow in the fetal descending aorta. The mean aortic blood flow velocity in the last trimester of normal pregnancies was 29.0 cm/s; the peak maximum velocity 97.3 cm/s and the mean blood flow 238.4 ml/min/kg. The blood flow velocity did not change significantly with gestational age, the aorta diameter showed a linear growth. During labour, the aortic blood flow in undistressed fetuses was not different from the flow recorded during late pregnancy. Fetal breathing movements modulate the flow velocity signals in the descending aorta, the inferior vena cava and the umbilical vein of the fetus; therefore, when quantifying fetal blood flow, only periods without fetal breathing movements should be considered. A group of fetuses with various types of cardiac arrhythmias was examined. Postextrasystolic potentiation was found to be present already during intrauterine life. The present method enables quantitative evaluation of the hemodynamic effects of cardiac arrhythmias.

Fetal central blood circulation in the third trimester of normal pregnancy--a longitudinal study. I. Aortic and umbilical blood flow.

Fetal central blood circulation was evaluated in 21 uncomplicated pregnancies every other week from the 27th gestational week till term. Blood flow in the fetal descending thoracic and abdominal aorta and in the intra-abdominal umbilical vein was measured with a combined ultrasound real-time and 2 MHz pulsed Doppler technique. The mean fetal blood velocities were fairly constant at the three measuring sites during the last trimester: 34.6 cm X s-1 (S.D. 5.5), 32.7 cm X s-1 (S.D. 5.5) and 12.6 cm X s-1 (S.D. 3.1), respectively. The aortic diameter increased with gestational age, whereas the umbilical vein diameter increased until the 34th gestational week followed by a stagnation. The mean weight-related blood flow in the fetal thoracic descending aorta decreased slightly towards term (from 240.8 ml X min-1 X kg-1 (S.D. 53.6) in the 28th week to 212.6 ml X min-1 X kg-1 (S.D. 37.3). In the umbilical vein, the corresponding blood flow decrease was linear and more pronounced: from 138.7 ml X min-1 X kg-1 (S.D. 76.0) to 65.2 ml X min-1 X kg-1 (S.D. 14.2). The results indicate that the placental proportion of fetal blood flow decreases with gestational age.

Fetal central blood circulation in the third trimester of normal pregnancy--a longitudinal study. II. Aortic blood velocity waveform.

Waveform of the maximum blood velocity recorded from the fetal descending thoracic and abdominal aorta was analyzed in a longitudinal study on 21 normal pregnancies from the 27th gestational week till term. Measurements of blood velocity were performed with combined real-time linear array and 2 MHz pulsed Doppler ultrasound technique every second week. The rising (RS) and the descending (DS) slopes did not change with gestational age in the thoracic descending aorta. The peak maximum velocity, the pulsatility index (PI) and the acceleration time percentage were constant during the last trimester of pregnancy, in both the thoracic and the abdominal aorta. In the former, the mean RS was 29.9 (S.D. 4.9), mean DS 5.3 (S.D. 0.9), mean peak velocity 115.6 cm X s-1 (S.D. 19.0), mean PI 1.96 (S.P. 0.31) and the mean acceleration time percentage 19.2% (S.D. 2.2). In the abdominal aorta, the mean RS was 25.7 (S.D. 5.6), mean DS 4.5 (S.D. 0.9), mean peak velocity 99.7 cm X s-1 (S.D. 18.8), mean PI 1.68 (S.D. 0.28) and the mean acceleration time percentage 19.1% (S.D. 2.2). The PI and the DS, considered to reflect mainly peripheral vascular resistance, were mutually related (r = 0.72). The acceleration time percentage, RS and PI did not show any relation to fetal heart rate or gestational age which justifies the use of gestational age-independent reference values for those parameters during the last 3 months of gestation, at least within the normal fetal heart rate range.

Long-term ailments due to anal sphincter rupture caused by delivery--a hidden problem.

Questionnaires concerning ailments were sent postpartum (mean two years) to 62 women with anal sphincter ruptures (ASR), who were compared with a matched control population. The frequency of anal sphincter rupture at the hospital during delivery in the period, 1978-82, was 0.7% (n = 63). Primiparity, instrumental deliveries, abnormal presentation, large babies and oxytocin stimulation were all risk factors. Of 59 women answering the questionnaire 37 (63%) stated that they had had ailments three months postpartum, mainly with pain and involuntary passage of flatus but also with dyspareunia and occasional incontinence of faeces. Long-term symptoms were noted by 28 (48%) of the women, mainly with involuntary passage of flatus but also perineal pain, dyspareunia and occasional incontinence of faeces. Long-term symptoms occurred in 7 (88%) of women with ASR also involving the anal mucosa, but only in 21 (39%) of those with ASR only. Three of the patients subsequently underwent reconstructive surgery, and three complained of psychological problems.

Anal sphincter function after delivery: a prospective study in women with sphincter rupture and controls.

Twenty-one consecutive women with anal sphincter muscle rupture during delivery (0.79%) and 15 controls were examined. The anal sphincter was immediately repaired in the study group and the function determined with anal profilometry at 3 days and 3 months after delivery, and in ten of the patients after 12 months. Anal sphincter strength was reduced soon after delivery in the controls but regained normal strength within 3 months. In the anal sphincter rupture group, an improvement was found over the first 3 months after delivery, but afterwards no further change occurred. The anal sphincter strength was significantly reduced compared to the control group, both soon after delivery and after 3 months. Their voluntary anal pressure increased from 1.7 kPa immediately after delivery to 3.2 kPa at 3 months in the study group and the corresponding values in the control group were 4.0 and 6.5 kPa, respectively. For the closing pressure, that is the resting pressure minus the rectal pressure, the values in the study group were 4.2 and 6.7 kPa, and in the control group 7.2 and 9.4 kPa, respectively. In the women with anal sphincter rupture, however, a significantly increased frequency of gas incontinence was found.

Placental morphology in relation to umbilical artery blood velocity waveforms.

The association between umbilical artery flow velocity waveforms, placental morphology and arterial vascular pattern was investigated in 30 pregnant women at risk for intra-uterine growth retardation. The blood velocity waveform was assessed in the umbilical arteries with pulsed Doppler ultrasound. Placentas from fetuses with an end-diastolic zero flow were small and thick with an extrachorial configuration, marginal cord insertion, magistral or mixed allantochorial vessel pattern and few cotyledons. The incidence and the extension of gross lesions were slightly increased in these placentas compared to placentas from fetuses with a normal S/D ratio (peak systolic velocity/minimum diastolic velocity). Placentas from fetuses with an increased S/D ratio (greater than +2SD) were large and thin with a high maximum diameter/maximum thickness ratio. Heavily smoking mothers were overrepresented in the group, with an increased S/D ratio and corresponding SGA infants. End-diastolic zero flow in the umbilical artery was strongly correlated with placental developmental abnormalities.

A comparative study of breast feeding after traditional postnatal hospital care and early discharge.

OBJECTIVE: To provide quality assurance for the care plan and working structure within the early discharge unit at the Women's Clinic, Central Hospital, Helsingborg, Sweden. DESIGN: Survey, using postal questionnaire. SETTING: The Women's Clinic, Central Hospital, Helsingborg, Sweden. PARTICIPANTS: 304 women with babies of six months of age, delivered at the Central Hospital, Helsingborg, between September and December 1993 and who, together with their baby, met the criteria for early discharge. Early discharge is generally defined in Sweden as discharge before 72 hours postpartum. MEASUREMENTS AND FINDINGS: Of the participants 41% chose early discharge (ED) and 59% chose traditional hospital care (THC). Four groups were studied for breast feeding frequency - THC primiparae, ED primiparae, THC multiparae and ED multiparae. Further division was made for breast feeding at 2, 4 and 6 months of age. The four main groups were examined for demographic differences. A difference was found in education level; early discharge mothers had a lower level of education than THC mothers. No significant difference was found for the frequency or duration of breast feeding between the early discharge and the traditional hospital care groups, despite the higher education level in the traditional hospital care group. IMPLICATIONS FOR PRACTICE: A possible explanation for this finding is that a care plan aimed at supporting the individual's responsibility and participation, providing relevant knowledge and a subliminal communication of trust in the competence of parent and child, is of particular significance for women with less education. The presence and participation of the baby's father at an early stage may also be a factor.

Transvaginal ultrasound and lactate dehydrogenase isoenzyme activity profile in uterine aspirate for diagnosis of endometrial carcinoma in women with postmenopausal bleeding.

Postmenopausal patients with vaginal bleeding (n = 72) were evaluated with the combination of transvaginal ultrasonography (TVS) and analysis of the lactate dehydrogenase (LD) isoenzyme activity profile in uterine fluid aspirates. TVS evaluation of the endometrium was classified as <5 mm, > or =5 mm, or poorly defined. The LD isoenzyme activity profile was characterized as abnormal or normal. Pathologic findings were further evaluated with diagnostic curettage. TVS found the endometrium to be > or =5 mm or poorly defined in 44 patients (61%). Endometrial carcinoma was found in 6 of 72 patients (8%). They appeared in the TVS groups endometrium >5 mm (n = 2) and endometrium poorly defined (n = 4) but not in the endometrium <5 mm. The LD isoenzyme activity profile was abnormal in the six malignant cases and in ten benign cases. Thus, the need for further evaluation with hysteroscopy and curettage was reduced to 16 cases. Since TVS had 100% sensitivity but only 42% specificity, it is suitable for first-level examination in patients with postmenopausal bleeding. The second-level method should have similarly high sensitivity but much higher specificity. The LD isoenzyme activity profile in uterine fluid aspirates had 100% sensitivity and 85% specificity. Another important feature is that the method is not sensitive to endometrial thickness, amount of sample, sampling device, or dilution. Thus, it is more reliable than aspiration histology. For every hysteroscopy or curettage that can be replaced by LD analysis, the cost is reduced by approximately EUR 720 or 540, respectively.

Circulatory effects of fetal cardiac arrhythmias.

The circulatory consequences of cardiac arrhythmia and its compensatory mechanisms were examined in utero in 37 fetuses. A combined real-time and 2-MHz pulsed Doppler technique was used to measure blood velocity for waveform analysis and flow estimation in the descending thoracic aorta of the fetuses. The pattern of blood velocity in the inferior vena cava was studied to classify the arrhythmia. Despite severe cardiac arrhythmias the aortic blood flow was within normal limits in all but one fetus which had associated cardiac malformation and congestive failure. The rising slope and the peak value of the maximum aortic velocity were significantly increased in the postpremature beats and in fetuses with atrioventricular block. The results support the validity of Frank-Starling's law for the fetal myocardium.

Noninvasive assessment of cranial blood circulation in the fetus.

The blood velocity in the common carotid artery, umbilical artery and descending aorta of 15 term fetuses with birth weights appropriate for gestational age and 20 fetuses, ultrasonically suspected of intrauterine growth retardation (IUGR), was recorded by means of a technique combining real-time linear-array ultrasonography and 2-MHz pulsed Doppler ultrasound. The waveform of the maximum blood velocity was characterized by a pulsatility index (PI) indicating peripheral vascular resistance. In the normal fetuses, the mean PI was 1.89 (+/- 0.07 SEM) in the common carotid artery, 0.93 (+/- 0.04) in the umbilical artery and 2.19 (+/- 0.06) in the descending aorta. In the IUGR fetuses, the PI was higher than in the normal fetuses in the umbilical artery (1.19 +/- 0.04; p less than 0.05) and lower in the carotid artery (1.48 +/- 0.03; p less than 0.05). The changes of the PI were even more pronounced in 10 IUGR fetuses in whom cardiotocographic signs (late decelerations) of imminent asphyxia were present. The results indicate an increase in the peripheral vascular resistance in the placental circulation and the lower body, and a decrease in the cranial vascular resistance in the growth-retarded fetuses. Furthermore, these findings suggest that in chronic and acute fetal distress, there is a redistribution of the fetal circulation favoring the brain.

Cerebral blood flow during labor in the human fetus.

A method is described for recording blood flow velocity waveforms from fetal cerebral vessels during labor, using a 2 MHz pulsed Doppler ultrasound technique. Fifteen healthy women with uncomplicated pregnancies and labor without signs of fetal distress participated in the study. With membranes ruptured and cervix orifice open 4-9 cm, the Doppler transducer was placed transvaginally on the fetal skull and the Doppler shift signals from the middle cerebral artery were located. The maximum velocity waveforms were recorded before, during and after uterine contractions and analysed off-line for pulsatility index (PI). No differences in the PI were found with regard to the uterine contractions. The results suggest an unchanged peripheral resistance in the fetal cerebral vascular bed during the first stage of normal labor.

Circulatory changes in fetuses with imminent asphyxia.

Blood flow was measured in 11 term fetuses who were later delivered by means of emergency caesarean section because of cardiotocographic changes indicating imminent asphyxia. Blood flow was recorded in the fetal descending aorta and in the intraabdominal part of the umbilical vein by combined real-time and 2-MHz pulsed Doppler ultrasound method. In all 11 fetuses, the waveform of the maximum aortic blood velocity was changed in a typical way with elimination of the diastolic flow (zero flow). In 4 of the fetuses, a short-lasting reversal of the diastolic flow occurred. In 5 fetuses, the pulsatility index of the aortic flow was increased, and the aortic volume flow was pathologically low in 3 fetuses. In the umbilical vein, the volume flow was within normal limits in all cases. The umbilical flow, which normally is continuous and nonpulsatile, showed heart-synchronous pulsations in 3 of the fetuses. The typical changes in the aortic diastolic flow occurred 1-3 days before the onset of the cardiotocographic changes. This suggests that the changes in the fetal aortic blood velocity might be a clinically useful early sign of imminent asphyxia.