The influence of race on fetal outcome

The purpose of this study was to examine racial differences in fetal death by gestational age among South Carolinians during 1999 to 2000 in an attempt to identify sociodemographic risk factors that may contribute to the refinement of care protocols. This historical cohort design appended the 1999 to 2000 South Carolina Vital Records fetal death file (N = 944) to the birth file (N = 99, 726) to perform secondary data analysis. Inclusion criteria were maternal South Carolina residency, delivery of a singleton in South Carolina, and racial identification as white or black. Independent associations between race (black or white), gestational age categories of deliveries (fetal death or live birth), and maternal sociodemographic characteristics (maternal age and prenatal care) were examined using chi2 analysis. Black and white fetal mortality rates (FMRs) were examined. Logistic regression was used to control for confounding variables. The study sample consisted of 63.4% white and 36.6% black for all deliveries; 40.89% white and 59.11% black for fetal deaths. There was a significant racial difference in gestational age categories, initiation of prenatal care, maternal age, and fetal death rates (p = 0.0001). The black FMR was nearly 2.5 times greater than the white rate (p < 0.0001; 95% confidence interval, 2.2 to 2.9). There was an independent association between race and gestational age at fetal death (p = 0.0001) as well as race and maternal age. Results did not remain statistically significant after controlling for confounding variables. In this study, we identified several factors associated with an increased risk of fetal death. However, after controlling for gestational age, the odds of fetal death among blacks were no longer significantly elevated in comparison to those of whites. Future studies that examine racial disparities should consider gestational age in analytic models. Identifying racial demographics and behavioral risks may contribute to refinements in care protocols for high-risk mothers in an effort to reduce fetal mortality.     

Prolonged fetal ritodrine exposure and immediate neonatal outcome

Ritodrine hydrochloride was administered over a period of two years to a total of 200 women in premature labor. One hundred sixty-two (81 per cent) of the women carried pregnancy to 35 weeks or longer. To determine the effect of ritodrine on the neonates, the duration and amount of exposure, onset of exposure, and interval between cessation of exposure and delivery were correlated with gestational age, birth weight, Apgar scores, mortality, and the presence of hypoglycemia, hyperbilirubinemia, respiratory distress, and intrauterine growth retardation. Infants exposed for six weeks or more (long-term exposure) were significantly heavier than those exposed for shorter periods (short-term exposure), a difference that was possibly attributable to differences in gestational age at birth. Infants who were exposed as fetuses to ritodrine beginning at 30 weeks' or less gestation needed phototherapy more often than did infants whose fetal exposure began at after 30 weeks' gestation. Neither duration of exposure nor gestational age at birth was a significant factor in hyperbilirubinemia. Of infants delivered at or after 35 weeks' gestation, 32 (20 per cent) experienced early hypoglycemia; and 26 of these (81 per cent) were exposed up to the day of delivery. This outcome differed significantly from that of infants whose exposure stopped at least one week before delivery. In addition, respiratory distress syndrome was more common in those infants exposed up until delivery (34 of 36).(ABSTRACT TRUNCATED AT 250 WORDS)     

Infection and fetal neurologic injury

PURPOSE OF REVIEW: Antepartum fetal exposure to infection/inflammation is a more important risk factor for brain injury than intrapartum hypoxia in both the term and preterm neonate. Such preexisting infection/inflammation might also provide the platform for subsequent intrapartum hypoxic-ischaemic damage. This review will discuss the complex interaction between fetal inflammatory response and neurotoxicity, and focus on the clinical implications of the synergistic interaction between infection/inflammation and hypoxia-ischaemia. RECENT FINDINGS: Current evidence indicates that inflammatory mediators are directly neurotoxic, and also sensitize the fetal brain tissue to a greater magnitude of damage by subsequent hypoxia-ischaemia by lowering the threshold at which hypoxia initiates neuronal cell apoptosis/cell death. SUMMARY: Further studies are urgently needed to characterize the fetuses at risk of damage, the duration of exposure required to cause injury, the influence of gestational age and whether Caesarean section may be protective. Until then clinicians should maintain a high level of surveillance in labours complicated by infection and avoid additional exposure to hypoxic-ischaemic insults.     

Counting fetal hiccups using a fetal movement acceleration measurement recorder

Objective: To clarify the degree of fetal hiccup occurrence by using a fetal movement acceleration measurement recorder.

Methods: A total of 23 pregnant women recorded fetal movements weekly or biweekly between 28 and 39 gestational weeks at home with the recorder. Fetal hiccups were defined as regular sharp oscillations – which occurred at 2–4?second intervals, more than 15 times per minute – on the maternal abdomen. The duration and frequency of the hiccup bouts were counted. The data were classified into an early (28–33 weeks) gestational group and a late (34–39 weeks) group, and compared between the two.

Results: A total of 164 records were obtained, and the total time analyzed amounted to 1035?hours. The mean incidence of a fetal hiccup bout at an early group was 0.19 times per hour, and it decreased to 0.15 at a late group (p?=?0.02). The durations of fetal hiccup bouts were 8.17 and 7.88?minutes at an early and a late group, respectively, with no significant difference (p?=?0.64).

Conclusions: The duration of a fetal hiccup bout did not change after 28 gestational weeks; however, incidence slightly decreased from an early to a late group.     

The effect of antenatal steroid administration on the fetal response to vibroacoustic stimulation

BACKGROUND: Betamethasone transiently suppresses multiple fetal biophysical activities, including breathing movements, limb and trunk movements, heart rate variability, and heart rate accelerations. Unnecessary iatrogenic delivery of preterm fetuses due to the false diagnosis of fetal compromise has been described in this setting. The sonographically observed startle response of the fetus to vibroacoustic stimulation has been described as another modality to provide reassurance about fetal well-being. It is unknown, however, whether the startle response is also suppressed by betamethasone. The purpose of this study was to examine the effect of betamethasone on this biophysical parameter. METHODS: A prospective cohort study. Vibroacoustic stimulation was applied to the maternal abdomen and fetal movement responses were sonographically observed prior to (0 hours), 48 hours after, and 96 hours after betamethasone administration. We recorded the presence or absence of the fetal startle response, and, if a response was present, graded semi-quantitatively the intensity of the movements (vigorous versus sluggish). RESULTS: Twenty-two of 26 fetuses (84.6%) displayed a vigorous vibroacoustic startle response prior to betamethasone administration, in comparison to three of 26 fetuses (11.5%) at 48 hours after exposure (p<0.0001). Eleven fetuses and eight fetuses displayed no startle response at all (p<0.0005), or a sluggish response only (p<0.0005) at 48 hours, respectively. At 96 hours after betamethasone exposure, no differences in the number of fetuses with a vigorous, sluggish, or absent response were observed in comparison to 0 hours. Stratification of cases by gestational age groups of 28-30 weeks versus 31-34 weeks showed similar response patterns. CONCLUSION: Antenatal betamethasone exposure transiently suppresses the sonographically observed fetal startle response to vibroacoustic stimulation. Accordingly, this modality cannot be used for the ascertainment of fetal well-being of steroid exposed fetuses. Betamethasone seems to suppress central nervous system dependent biophysical activities. including the brain-stem dependent vibroacoustic startle reflex.     

Influence of gestational age and fetal heart rate on the fetal mechanical PR interval.

OBJECTIVE: The fetal mechanical PR interval obtained via pulsed Doppler has previously been demonstrated to correlate with electrocardiographic PR interval measured in the neonate. We sought to further analyze the influence of fetal heart rate and gestational age upon the fetal mechanical PR interval. METHODS: We searched our database for mechanical PR intervals, which were obtained during fetal echocardiography performed in our antenatal diagnostic unit. We included fetuses with a normal cardiac structural survey. The mechanical PR interval is measured from the A wave of the mitral valve to the beginning of ventricular systole corresponding to the opening of the aortic valve. Linear regression curves were generated to examine the correlation of mechanical PR interval with gestational age and fetal heart rate. Analysis of variance was used to compare the mean variation across three gestational age groups: 17-21.9 weeks (n = 24), 22-25.9 weeks (n = 52) and 26-38 weeks (n = 20). RESULTS: Mechanical PR intervals were measured in 96 fetuses with normal fetal echocardiography. The mechanical PR interval was 123.9 +/- 10.3 ms (mean +/- SD), with a range of 90-150 ms. Linear regression curves correlating mechanical PR interval with fetal heart rate and gestational age demonstrated a flat slope with R2 = 0.016, p = 0.22 and R2 = 0.0004, p = 0.85, respectively. The mechanical PR interval measured over the three gestational ages was as follows (mean +/- SD): 122.3 +/- 10.5 ms for 17-21.9 weeks; 125.0 +/- 9.6 ms for 22-25.9 weeks; and 123.1 +/- 11.9 ms for 26-38 weeks. Analysis of variance revealed no difference among the mechanical PR interval means measured over the three gestational age groups (p = 0.53). CONCLUSIONS: Fetal mechanical PR interval ranges from 90 to 150 ms in fetuses with sonographically normal fetal cardiac structure and rate. The mechanical PR interval appears to be independent of gestational age and fetal heart rate.     

Effects of vibratory acoustic stimulation on human fetal breathing and gross fetal body movements near term

Twenty-five pregnant women between 36 and 40 weeks' gestational age were studied to examine effects of a 5-second external vibratory acoustic stimulus on fetal breathing and gross fetal body movement patterns. When the study period was compared with the control period, there was an immediate significant decrease in the incidence of fetal breathing movements that persisted for 1 hour after the stimulus. Moreover the fetal breathing pattern was more irregular for the hour after the stimulus. There was also a significant but delayed increase in the incidence of gross fetal body movements that persisted for 1 hour after the stimulus. We hypothesize that an external vibratory acoustic stimulus causes a change from a state of sleep to a state of wakefulness in near-term healthy fetuses.     

Human fetal breathing response to intravenous glucose is directly related to gestational age

This prospective longitudinal study examined human fetal breathing activity over the second half of pregnancy both in the fasting state and after intravenous glucose administration. There was a linear relationship between gestational age and percent time spent breathing after glucose between 19 and 38 weeks' gestation. However, no such correlation could be demonstrated between gestational age and fetal breathing activity in the fasting state.     

Chorionic villus sampling significantly affects fetal cardiovascular function.

OBJECTIVE: To assess the effects of chorionic villus sampling (CVS) on fetal heart rate (FHR). METHODS: A prospective longitudinal study was conducted among 300 patients undergoing transabdominal CVS between 8 and 13 weeks of gestation. Duration of the procedure, number of needle passes, sample weight, maternal age, fetal gender, and FHR response to CVS were recorded. RESULTS: The FHR before but not after CVS was inversely correlated with gestational age (r = -0.406, p < 0.001). Conversely, following CVS, no correlation was observed between FHR and gestational age (r = -0.06, p = 0.27). The difference between FHR after CVS and that obtained before CVS (delta FHR) increased with increasing gestational age at sampling (r = 0.372, p < 0.0001), decreased with increasing specimen weight (r = -0.16, p = 0.01) and increased with increasing maternal age (r = 0.22, p < 0.0001). Duration of the procedure, fetal gender and number of needle passes did not affect delta FHR. Multiple logistic regression indicated that gestational age at CVS and maternal age but not the other variables significantly affected delta FHR and together they accounted for over 22% of the variance (R(2) = 0.224, p < 0.0001). CONCLUSIONS: In summary, our results suggest that acute fetal hemodynamic changes accompany CVS and that these changes vary with gestational age.     

胎儿医学框架下的氯化钾减胎术应用于早中孕期多胎妊娠的经验——来自单一中心的临床研究

目的:总结我院在胎儿医学框架下建立的氯化钾减胎术在早中孕期应用于多胎妊娠的临床经验。方法:回顾研究2011年1月至2013年12月在上海市第一妇婴保健院于孕11~16周行氯化钾减胎的32例患者的临床资料,记录围手术期母胎并发症及分娩28天后围产儿结局,总结单一中心采用该技术积累的相关经验。结果:患者的平均减胎手术孕周(13.81±0.84)周,平均分娩孕周(34.52±5.78)周,平均新生儿出生体重(2541±665.9)g。围产儿存活率为92.8%,母体并发症包括妊娠期高血压1例,重度子痫前期1例,未发生严重的分娩并发症。结论:在胎儿医学框架下进行的氯化钾减胎技术用于早中孕期减胎安全有效,改善了多胎妊娠的围产儿结局。     

Development of fetal organs and adaptation to extrauterine life

Under unsatisfactory environmental conditions, such as the mother's illness, placental insufficiency, PROM, etc., the fetus must make the transition to extrauterine life from an unfortunate intrauterine existence. The adaptation process of the fetus to extrauterine environment in these cases is extreme importance. In our present investigation, we studied the developmental pattern of the functions of each fetal organ and the specific aspects of fetal metabolism. Using the brush border technique, we clarified that the fetal absorptional function of intestine developed from the 24th week of gestation and reached adult level in 32nd gestational weeks. The fetal renal reabsorption function developed from the 30th week of gestation and reached adult level in 36 gestational weeks. The liver function (enzymatic activity, etc.) remained low during the entire fetal life and developed gradually after birth. Taurine plays an important metabolical role and has a specific transport system during fetal life. The coagulation of vitamin K-dependent factors and activity remained low level at 27-31st gestational week, reaching full term level after 30 days. The switching of HbF to HbA was delayed more significantly in premature infants than in full term infants, but this delay of switching is effectively corrected by the increase of 2.3 DPG in premature infants. Immune response remained immature even in the full term fetus, but the non-specific immune response (NK activity, LAK activity, etc.) developed in the early fetal period and showed characteristic activity. The steroids which originated from the fetal-placental unit related intimately to the continuity of pregnancy and fetal development.     

Minor fetal hemoglobins in relation to gestational age

Cord blood samples were obtained at delivery in 44 normal women, at gestational periods ranging from 27 to 41 weeks. All women had a normal glucose screening test and 15 were delivered preterm. With the use of Biorex 70 chromatography, red cell lysates were analyzed to determine the percentages of the different hemoglobin (Hb) components, i.e., HbF1a+b, HbFlc, HbFo, and HbA. The percentage of HbFla+b in fetal blood was higher than the corresponding percentage in adult blood. The percentages and ratios of the various Hb components were compared in preterm and term fetuses and their correlation to gestational age was tested. HbF and HbF/A ratios were higher in preterm fetuses and were negatively correlated with gestational age. HbA and HbA/F ratios were lower in preterm fetuses than in term fetuses and correlated positively with gestational age. The percentages of minor components HbFla+b, and HbFlc were not significantly different in the preterm and the term fetuses, and they did not have statistically significant correlation with gestational age. However, the ratios of these minor hemoglobins to HbF, i.e., HbFla+b/HbF, and HbFlc/HbF and HbFl/HbF were found to be significantly higher in term fetuses as compared to preterm fetuses and to correlate positively with gestational age. This is probably due to the gradual lengthening of the life span of fetal erythrocytes as term approaches, which results in the erythrocytes' increased exposure to the glycolytic intermediates and possibly to glucose.     

Cytogenetic study of amniotic fluid in the evaluation of fetal death

Cytogenetic study is an important part of the evaluation of intrauterine fetal death. Many tissue cultures fail to grow because of maceration and autolysis of the fetal tissues. We evaluated eight amniotic fluid cytogenetic cultures from patients whose fetus had died. All patients had sonographic evidence of Spalding's sign. In four patients, urea and PGF2 alpha were simultaneously injected into the amniotic cavity. Seven amniotic cultures, gestational age 19 to 33 weeks, grew successfully, even when a tissue culture obtained after delivery failed to grow. One culture, gestational age 36.5 weeks, failed to grow and could not be analyzed. The use of amniotic fluid culture for cytogenetic evaluation of fetal death, obtained at the time of diagnosis, is superior to culture of fetal tissue obtained after delivery. The amniocentesis may also serve for intra-amniotic induction of labor.     

Gestational age and fetal biophysical assessment

With improved neonatal care, biophysical assessment to detect fetal asphyxia is used increasingly at an earlier gestational age. We have tested five fetal biophysical variables: nonstress test, fetal breathing movements, fetal movements, fetal tone, and amniotic fluid volume 11,012 times in 5582 singleton fetuses in whom there was a normal perinatal outcome. The nonstress test and fetal breathing movements were more likely to be abnormal at 26 to 33 weeks' gestation compared with 34 to 41 weeks. The nonstress test, fetal breathing movements, fetal tone, and amniotic fluid volume were more likely to be abnormal at 42 to 44 weeks' gestation compared with 37 to 41 weeks. Fetal biophysical tests should be interpreted in relation to gestational age.     

Successful patching of iatrogenic rupture of the fetal membranes

Rupture of the fetal membranes is a common, but potentially serious complication of invasive fetal procedures. Quintero described a technique to seal the fetal membrane defect by means of a bloodpatch, usually called 'amniopatch' in this application. The successful use in two consecutive patients with ruptured membranes after a fetoscopic intervention at respectively 17 and 22 weeks' gestational age is described, together with a literature review of published experience.     

The relationship between fetal activity and behavioral states and fetal breathing movements in normal and growth-retarded fetuses

The incidence of fetal breathing was studied during the course of behavioral state observations on 28 low-risk fetuses between 32 and 40 weeks' gestational age and on 12 growth-retarded fetuses between 36 and 40 weeks. Real-time ultrasound scanners were used to detect fetal eye, body, and breathing movements, and the fetal heart rate was recorded continuously. The mean duration of the observation sessions was 110 minutes. The mean incidence of fetal breathing was greater during periods of fetal activity (body and eye movements present, greater heart rate variability) than during quiescence (body and eye movements absent, narrowed heart rate variability) at all gestational ages studied in both low-risk and growth-retarded fetuses. During periods when one of the state variables (body movements, eye movements, heart rate pattern) was in its active condition while the other two were quiet, or the reverse, the incidence of fetal breathing was intermediate between those found when all three state variables were in agreement. After behavioral states had developed, at 38 and 40 weeks, the mean incidence of fetal breathing in the low-risk fetuses was greater during active states than during the quiet state. There was no apparent increase in the degree of linkage between fetal breathing and other expressions of fetal activity after the emergence of behavioral states.     

Fetal loss in threatened abortion after embryonic/fetal heart activity.

OBJECTIVES: To study the incidence of fetal loss in threatened abortion after detection of embryonic/fetal heart activity. METHODS: A prospective study was performed on pregnant women with clinically diagnosed threatened abortion between 6 and 14 weeks of gestation. All had a good menstrual history and the calculated gestational age using crown-rump length in the first trimester ultrasound was in agreement. Embryonic/fetal heart rate measurements were obtained by a 5 MHz vaginal probe using M-mode and real-time B mode imaging. All cases were followed up with respect to pregnancy outcomes. The data were analyzed using the SPSS computer program. RESULTS: Eighty-seven pregnant women were included in the study. There were three pregnancies (3.4%) which resulted in fetal loss before 20 weeks of gestation. In viable pregnancies, the mean embryonic/fetal heart rate increased with advancing gestational age. The individual values of embryonic/fetal heart rate for fetal losses were within the reference range. CONCLUSIONS: The incidence of fetal loss in threatened abortion after detection of embryonic/fetal heart activity was 3.4%. There was no evident pattern of bradycardia or tachycardia that signaled the incipient of viability.     

Influence of gestational age and fetal heart rate on the fetal mechanical PR interval

Objective: The fetal mechanical PR interval obtained via pulsed Doppler has previously been demonstrated to correlate with electrocardiographic PR interval measured in the neonate. We sought to further analyze the influence of fetal heart rate and gestational age upon the fetal mechanical PR interval.

Methods: We searched our database for mechanical PR intervals, which were obtained during fetal echocardiography performed in our antenatal diagnostic unit. We included fetuses with a normal cardiac structural survey. The mechanical PR interval is measured from the A wave of the mitral valve to the beginning of ventricular systole corresponding to the opening of the aortic valve. Linear regression curves were generated to examine the correlation of mechanical PR interval with gestational age and fetal heart rate. Analysis of variance was used to compare the mean variation across three gestational age groups: 17–21.9 weeks (n?=?24), 22–25.9 weeks (n?=?52) and 26–38 weeks (n?=?20).

Results: Mechanical PR intervals were measured in 96 fetuses with normal fetal echocardiography. The mechanical PR interval was 123.9?±?10.3?ms (mean?±?SD), with a range of 90–150?ms. Linear regression curves correlating mechanical PR interval with fetal heart rate and gestational age demonstrated a flat slope with R²?=?0.016, p?=?0.22 and R²?=?0.0004, p?=?0.85, respectively. The mechanical PR interval measured over the three gestational ages was as follows (mean?±?SD): 122.3?±?10.5?ms for 17–21.9 weeks; 125.0?±?9.6?ms for 22–25.9 weeks; and 123.1?±?11.9?ms for 26–38 weeks. Analysis of variance revealed no difference among the mechanical PR interval means measured over the three gestational age groups (p?=?0.53).

Conclusions: Fetal mechanical PR interval ranges from 90 to 150?ms in fetuses with sonographically normal fetal cardiac structure and rate. The mechanical PR interval appears to be independent of gestational age and fetal heart rate.     

12例胎儿室上性心动过速的治疗

目的研究胎儿心动过速的临床治疗方案。 方法回顾性分析2011年1月至2015年12月在广州医科大学附属第三医院胎儿医学科进行系统超声检查的45 566例孕妇的结果,59例(3.62‰)通过胎儿超声心动图和M型超声诊断为胎儿心律不齐,其中12例诊断为胎儿室上性心动过速(superventricular tachycardia, SVT),对3例SVT病例分别给予盐酸普罗帕酮、美托洛尔和地高辛治疗,另外9例患者给予期待治疗并积极治疗母体并发症。 结果3例药物治疗患者中1例伴有胎儿水肿经药物治疗无效选择终止妊娠,另外2例治疗效果良好,其胎儿健康;9例期待治疗患者中,1例13周发生胎死宫内,1例孕18^＋6周发生难免流产,1例孕35^＋6周合并中央性前置胎盘采取剖宫产分娩,其余6例患者预后良好,足月分娩。 结论胎儿发生阵发性室上性心动过速不伴有水肿,可予期待治疗,结局良好;胎儿发生持续性室上性心动过速不伴有水肿,可经药物治疗转律效果良好,若伴有严重水肿,药物治疗效果较差。     

Effect of cocaine on fetal kidney and bladder function

OBJECTIVE: To study the relationship between the bladder cycle and urine output by the fetus and the effect of intrauterine exposure to cocaine on both. METHODS: Fetal hourly urine production rate and bladder cycle length were measured in two groups of pregnant women between 20 and 40 weeks of gestation. A control group of 59 normal pregnancies were examined longitudinally to establish reference ranges. A study group of 36 women with a history of cocaine abuse; urine was positive for cocaine only. They were examined once. The diameters of fetal bladder were measured to calculate bladder volume and hourly urine output. The bladder cycle was the time interval between two successive acts of voiding by the fetus. RESULTS: In the normal group, fetal hourly urine production had a positive linear correlation with the gestational age, with mean urine volume of 3.38 ml/h at 20 weeks and 48.36 ml/h at 40 weeks. The bladder cycle also had positive linear association with the advancing gestational age, with 26+/-4.76 min at 20 weeks and 65.2+/-14.85 min at 40 weeks. When compared with the corresponding gestational ages, the cocaine-exposed group showed a significant decrease (P < 0.0001) in the hourly urine production and the bladder cycle. There was significant correlation (r = 0.95, P < 0.001) between bladder cycle and hourly urine output in the control group, but not in the cocaine group. CONCLUSION: Cocaine decreases fetal urine output and bladder cycle.