Ominous Fetal Heart Rate Patterns Research Articles

Lactate in scalp and cord blood from fetuses with ominous fetal heart rate patterns

Objective: We investigated lactate concentrations in fetal scalp and cord blood to determine the sources of fetal lactacidosis in fetuses with ominous heart rate patterns. Methods: Cord blood was collected from newly delivered infants who had been monitored by fetal scalp blood sampling during labor. In 250 cases umbilical arterial and venous cord blood lactate levels were measured. We assessed the umbilical arterial lactate concentrations in relation to the venous lactate levels, the arterial pH level, base excess, and arteriovenous lactate differences in cord blood. In 103 cases the levels of lactate in fetal scalp blood, sampled within 60 minutes of delivery, were compared with those in the umbilical artery and vein and the pH level and base excess immediately after birth. Results: Lactate level in the umbilical artery showed a significant correlation to that in umbilical venous blood ( r = .84, P < .001), to arteriovenous lactate differences ( r = .52, P < .001), as well as to pH ( r = −.55, P < .001) and base excess ( r = −.63, P < .001) in arterial cord blood. Lactate concentrations in fetal scalp blood shortly before delivery showed a significant correlation to lactate levels in the umbilical arterial ( r = .65, P < .001) and venous blood ( r = .62, P < .001). Conclusion: The study indicates a close correlation between lactate levels in arterial and venous cord blood, as well as between the lactate levels and pH and base excess in cord arterial blood in patients with ominous fetal heart rate patterns. We also found an increased fetal contribution with increasing lactacidemia. Lactate concentrations in fetal scalp blood correlated well with those in cord arterial and venous blood.

Lactate in Scalp and Cord Blood From Fetuses With Ominous Fetal Heart Rate Patterns

In Brief Objective We investigated lactate concentrations in fetal scalp and cord blood to determine the sources of fetal lactacidosis in fetuses with ominous heart rate patterns. Methods Cord blood was collected from newly delivered infants who had been monitored by fetal scalp blood sampling during labor. In 250 cases umbilical arterial and venous cord blood lactate levels were measured. We assessed the umbilical arterial lactate concentrations in relation to the venous lactate levels, the arterial pH level, base excess, and arteriovenous lactate differences in cord blood. In 103 cases the levels of lactate in fetal scalp blood, sampled within 60 minutes of delivery, were compared with those in the umbilical artery and vein and the pH level and base excess immediately after birth. Results Lactate level in the umbilical artery showed a significant correlation to that in umbilical venous blood (r = .84, P < .001), to arteriovenous lactate differences (r = .52, P < .001), as well as to pH (r = −.55, P < .001) and base excess (r = −.63, P < .001) in arterial cord blood. Lactate concentrations in fetal scalp blood shortly before delivery showed a significant correlation to lactate levels in the umbilical arterial (r = .65, P < .001) and venous blood (r = .62, P < .001). Conclusion The study indicates a close correlation between lactate levels in arterial and venous cord blood, as well as between the lactate levels and pH and base excess in cord arterial blood in patients with ominous fetal heart rate patterns. We also found an increased fetal contribution with increasing lactacidemia. Lactate concentrations in fetal scalp blood correlated well with those in cord arterial and venous blood. During labor with fetal distress, lactate levels in scalp blood obtained shortly before delivery are correlated with those in cord blood.

Intrapartum fetal heart rate patterns in pregnancies complicated by hypertension: A cohort study

Intrapartum fetal heart rate patterns were investigated in pregnancies complicated by hypertension in a cohort study. The total number of live births was 2400 and the frequency of hypertension was 8.8%. The study group comprised 2023 normotensive and 200 hypertensive deliveries. Dates of all pregnancies were established at an ultrasound examination in week 17. Ominous intrapartum fetal heart rate patterns were significantly more common in hypertensive deliveries than in normotensive deliveries (20.5% versus 7.6%). The women with hypertension were compared with a group of control women matched for age, parity, induction of labor, and gestational week (20.5% versus 6.5%). In hypertensive women ominous fetal heart rate tracings were frequently associated with primiparity, induced labor, epidural block, delivery of a growth-retarded fetus, and beta 1-adrenergic receptor blockers. Ominous fetal heart rate patterns were less common in hypertensive women without these risk factors; still the significant differences in comparison with normotensive women remained. The hypertensive pregnancies accounted for no less than 21.0% of all ominous intrapartum fetal heart rate patterns, whereas 13% of all cases of ominous intrapartum fetal heart rate patterns could be attributed to the excess frequency in hypertensive pregnancies.

A study on intrauterine fetal resuscitation with terbutaline

A randomized study on the effect of terbutaline on fetal distress was carried out in 20 patients who showed evidence of ominous fetal heart rate patterns and fetal scalp blood pH values of less than 7.25. Of those, 11 received terbutaline (study group) and nine did not (control group). There was a significant improvement in the acid-base status of the fetus in the study group compared with those in the control group (p less than 0.01). No significant maternal or fetal morbidity occurred in the study group. Apgar scores at 1 minute were 7 or greater in 10 of the 11 study subjects whereas only four of the nine control subjects had a score of 7 or greater. These results suggest that terbutaline may become a useful agent in the treatment of intrauterine fetal distress.

Cord blood serum creatine kinase isoenzymes with placental dysfunction.

It has been suggested that perinatal asphyxia is not generally followed by neurological impairment unless there is preexisting chronic fetal distress. In cases of brain damage one can observe elevated levels of CK-BB. The purpose of our study was to evaluate CK isoenzymes in umbilical cord blood sera of newborns affected by chronic fetal distress. Fetal distress reflected by placental dysfunction was characterized by a diminished HPL level and decreased activity of CAP. We estimated CK isoenzymes with the use of DEAE-sepharose CL-6B column chromatography. Total CK activity was measured using kits supplied by Boehringer-Mannheim (Monotest CK-NAC aktiviert). The clinical state of examined newborns was estimated. Investigations were carried out in the group of 57 infants delivered after 37 weeks of gestation. Total CK activity in cord sera ranged from 40 to 400 U/l. Our results showed a significant rise of CK-BB activity in cord sera of newborns delivered from pregnancies with placental dysfunction (figure 2) as well as in cases of asphyxiated infants (figure 3). We were unable to demonstrate differences in total CK, CK-MM and CK-MB activities in all examined groups of newborns. Other authors have confirmed that severe asphyxia results in increase in CK-BB activity in cord blood. Infants with ominous fetal heart rate patterns have higher CK-BB activity. There are several possible sources for CK-BB activity in umbilical cord blood sera, i.e. fetal brain, lung, gastrointestinal tract, placenta and uterus. It appears that the brain is most likely the source of elevated CK-BB activity found in cord blood in cases of placental dysfunction.

Perinatal events and intraventricular/subependymal hemorrhage in the very low-birth weight infant

One hundred nineteen very low-birth weight infants were studied to see whether intrapartum fetal distress with or without acidosis correlated with the development of intraventricular and subependymal hemorrhage. Of 112 infants studied prospectively, 24% (27112) had intraventricular/subependymal hemorrhage documented by real-time ultrasound studies shortly after birth; only 4.4% (5112) had severe hemorrhage (grade 34). Ominous fetal heart rate patterns occurred in 50% of monitored infants with severe intraventricular/subependymal hemorrhage compared to 8% of matched controls (p < 0.01). Reassuring fetal heart rate patterns were more predominant in infants without intraventricular/subependymal hemorrhage (p < 0.05). Neonatal depression and the need for assisted ventilation beyond the immediate delivery period were more frequent in infants who developed intraventricular/subependymal hemorrhage. Antepartum and intrapartum complications, fetal presentation, cesarean section, duration of labor, hyaline membrane disease, and volume expansion appeared to play no role in the incidence of intraventricular/subependymal hemorrhage. Preliminary data presented here suggest that intrapartum fetal distress and acidosis may be significant factors in predicting which very low-birth weight infant will develop intraventricular/subependymal hemorrhage. The condition of the infant at birth may be more significant with respect to the extent of intraventricular/subependymal hemorrhage than a variety of obstetric variables. Aggressive management of appropriately selected patients and judicious resuscitation of the very low-birth weight infant may keep the incidence of severe intraventricular/subependymal hemorrhage at a minimum, thereby optimizing neurological outcome for this high-risk group.

Neurodevelopmental outcome and electronic fetal heart rate monitoring in a neonatal intensive care population.

In a one-year population, 1977, of newborn infants admitted to the Neonatal Intensive Care Unit (NICU) the incidence of persistent neurodevelopmental handicaps was 3%, i.e. 13 of 427 survivors at 2 years of age. Transient abnormalities during the first 6 months of life were found in 63 infants, but after 6 months of age they were all normal at follow-up examinations. Most mothers with infants showing transient abnormalities or persistent handicaps had a high-risk pregnancy but one-third (35.5%) had a low-risk pregnancy and in this group 4 out of 7 cases with persistent major neurodevelopmental handicaps were found. In the total one-year population, 6% showed ominous fetal heart rate patterns (FHR) in labor compared with 31% of infants with later abnormalities and handicaps. Furthermore, all 13 infants with persistent handicaps had a normal Apgar score at 5 min, indicating that Apgar scoring was less predictive than FHR for neurodevelopmental outcome. Altogether 54 infants born in 1977 were small for gestational age (SGA): 33 NICU-treated and 21 not NICU-treated. Seven (6 NICU-treated, 1 not NICU-treated) had transient abnormalities (12.9%). No SGA infant developed persistent handicaps. The results suggest an improved obstetric and neonatal care of these infants.

Fetal scalp blood lactate as an indicator of intrapartum hypoxia.

Fetal scalp blood lactate was measured during labour by a simple, rapid method and its value as an indicator of fetal intrauterine hypoxia was assessed and compared with that of pH measurement. The normal ranges of lactate concentration and of pH values were calculated. Significantly higher concentrations of lactate and lower pH values were found in samples of scalp blood taken close to delivery from babies with Apgar scores of less than or equal to 6 at 1 min compared with those from healthy babies with Apgar scores of greater than or equal to 7 at 1 min. A similarly significant difference was observed between the cord blood lactate and pH values of these two groups of babies. Ominous fetal heart rate patterns were associated with higher lactate concentrations and lower pH values in fetal scalp blood than were normal fetal heart rate patterns. The measurement of fetal scalp blood lactate or pH, or continuous electronic fetal heart rate monitoring were equally good at predicting the condition of the infant at birth.

Fetal heart rate patterns and development in the first year of life

The development of 50 high-risk infants who were provided intrauterine monitoring during labor was prospectively evaluated. Twelve infants had normal fetal heart rate patterns, 16 moderate-severe variable patterns, and 22 severe variable or late deceleration patterns. The parity, socioeconomic status, race of the mothers, and sex of the infants were similar in each group. The infants were examined neurologically 48 to 72 hours after birth and at 2, 4, 6, 9, and 12 months of age. Denver Developmental Standard testing was performed at 2, 4, 6, 9, and 12 months of age. A statistically significant developmental bias was seen favoring those infants with normal fetal heart patterns. Fetal heart rate patterns predicted abnormal performance more accurately than did Apgar scores. Although this data is incomplete, the duration of ominous fetal heart rate patterns appears to adversely affect development.

A Comparative Study of Uterine Activity in Labour Induced with Prostaglandin F2α Or Oxytocin and in Spontaneous Labour

The uterine contraction patterns and the changes in fetal heart rate (FHR) were studied in cardiotocographic recordings from 26 women in oxytocin-induced labour, 26 women in PGF2alpha-induced labour and 24 women during the later part of spontaneous labour. The contraction patterns and their effect on the FHR did not differ between the three groups. During the course of labour an increasing steepness of the upward slope of the contraction wave with increasing intensity of the contraction was found. High frequency of atypical contraction patterns, suggesting some degree of uterine incoordination was found during the active phase of labour in 10 patients, 8 of whom were primiparae. This incoordination could not be related to the effect of induction with either drug. Incoordinated contractions were associated with longer duration of labour and a tendency to more pronounced acidosis in the infant at birth, although mean values still fell in the normal range. Ominous FHR patterns were only seen in 2 cases of uterine hyperactivity during induction of labour.

On-line diagnosis of ominous fetal heart rate patterns: A warning device

A warning device has been developed for the on-line detection of ominous fetal heart rate (FHR) patterns. The FHR’s present with 1,600 contractions were studied in 20 patients. When no ominous FHR deceleration patterns are present, the instrument diagnoses agreed with those of a trained observer over 93 per cent of the time. When ominous FHR deceleration patterns are present, some type of FHR deceleration pattern was diagnosed in a high percentage of instances: variable deceleration, 71 of 73; late-deceleration episodes (2 or more late decelerations), 57 of 57; mixed variable and late deceleration, 146 of 147. A warning device has been developed for the on-line detection of ominous fetal heart rate (FHR) patterns. The FHR’s present with 1,600 contractions were studied in 20 patients. When no ominous FHR deceleration patterns are present, the instrument diagnoses agreed with those of a trained observer over 93 per cent of the time. When ominous FHR deceleration patterns are present, some type of FHR deceleration pattern was diagnosed in a high percentage of instances: variable deceleration, 71 of 73; late-deceleration episodes (2 or more late decelerations), 57 of 57; mixed variable and late deceleration, 146 of 147.

Additional observations on “pathologic” bradycardia

Although stethoscopic evaluation of the fetal heart rate (FHR) has been used for over 70 years for the early detection of fetal distress, it has limited value for this purpose. With the development of electronic techniques, specific FHR patterns indicating umbilical cord compression and uteroplacental insufficiency have been observed. Past and recent fetal animal studies support the concept that ominous FHR patterns indicating fetal asphyxia exist. This is particularly true of fetal rhesus monkey studies where in utero partial asphyxia was associated with the FHR pattern of late deceleration and subsequent fetal monkey brain damage at autopsy. In view of current developments, the present direction of research and clinical use of fetal monitoring seems not unreasonable.

Fetal heart rate patterns following epidural anaesthesia and oxytocin infusion during labour.

SummaryBy direct continuous electronic monitoring 360 fetuses were observed for cardiac decelerations occurring late in the uterine contraction cycle during labour in four maternal treatment groups. Neither epidural anaesthesia nor oxytocin stimulation was used in 119 patients (Group A); oxytocin stimulation with other forms of anaesthesia was used in 41 patients (Group B); epidural anaesthesia without oxytocin in 135 patients (Group C); and the combination of epidural anaesthesia and oxytocin stimulation in 65 patients (Group D). The frequency of uteroplacental insufficiency (Hon, 1967), patterns in Group A was 16.8 per cent; Group B, 26.8 per cent; Group C, 24.4 per cent and Group D, 40 per cent.When a fall in maternal systolic blood pressure of greater than 20 mm. Hg occurred during epidural anaesthesia, 72 per cent of fetuses developed utero‐placental insufficiency patterns. When uterine hypertonus developed during oxytocin infusion 50 per cent of fetuses, including 5 of 7 fetuses subjected to tetanic contractions, developed late decelerations.Most fetuses who developed late decelerations had normal heart rate patterns before treatment. Control of oxytocin infusion and correction of hypotension by maternal hydration and avoidance of the supine position were usually accompanied by improvement in these ominous fetal heart rate patterns. There was no difference in neonatal outcome among the various treatment groups.