Normal Fetal Heart Rate Tracings Research Articles

Six vs 12 hours of Foley catheter balloon placement in the labor induction of multiparas with unfavorable cervixes: a randomized controlled trial

Planned 6- vs 12-hour placement of the double-balloon catheter for cervical ripening in labor induction hastens delivery. The Foley catheter is low-priced and typically performs at least as well as the proprietary double-balloon devices in labor induction. Maternal satisfaction with labor induction is usually inversely related to the speed of the process. This study aimed to compare Foley balloon placement for 6 vs 12 hours in the labor induction of multiparas with unfavorable cervixes. A randomized controlled trial was conducted in a university hospital in Malaysia from January to October of 2022. Eligible multiparous women admitted for induction of labor for various indications were enrolled. Participant inclusion criteria were multiparity (at least 1 previous vaginal delivery of ≥24 weeks' gestation), age ≥18 years, term pregnancy >37 weeks' gestation, singleton pregnancy, cephalic presentation, intact membranes, normal fetal heart rate tracing, no significant contractions (< 2 in 10 minutes), and unfavorable cervix (Bishop score < 6). Participants were randomized after successful Foley balloon insertion for the balloon to be left in place for 6 or 12 hours of passive ripening before removal to check cervical suitability for amniotomy. The primary outcomes were the induction-to-delivery interval and maternal satisfaction with the allocated intervention assessed using a visual numerical rating scale (0-10). Secondary outcomes were derived in part from the core outcome set for trials on induction of labor (Core Outcomes in Women's and Newborn Health [CROWN]). Maternal outcomes were change in first Bishop score after intervention, use of additional method for cervical ripening, time to delivery after balloon removal, mode of delivery, indication for cesarean delivery, duration of oxytocin infusion, blood loss during delivery, presence of third- or fourth-degree perineal tear, maternal infection, use of regional analgesia in labor, length of hospital stay, intensive care unit (ICU) admission, cardiorespiratory arrest, and need for hysterectomy. The secondary neonatal outcomes were Apgar score at 1 and 5 minutes, neonatal intensive care unit (NICU) admission, cord blood pH, neonatal sepsis, birthweight, birth trauma, hypoxic-ischemic encephalopathy, or need for therapeutic hypothermia. Analyses were conducted with the t-test, Mann-Whitney U test, chi-square test, and Fisher exact test, as appropriate. A total of 220 women were randomized (110 to each intervention). Regarding the 2 primary outcomes, the induction-to-delivery intervals were a median (interquartile range) of 15.9 (12.0-24.0) and 21.6 (17.3-26.0) hours (P<.001), and maternal satisfaction scores were 7 (6-8) and 7 (6-8) (P=.734) for 6- and 12-hour placement, respectively. The following rates were observed for 6- and 12-hour placement, respectively: sequential use of additional cervical ripening agent (Foley reinsertion)-29 per 110 (26.4%) and 13 per 110 (11.8%) (relative risk, 2.23; 95% confidence interval, 1.23-4.10; P=.006); spontaneous balloon expulsion-22 per 110 (20.0%) and 37 per 110 (33.6%) (relative risk, 0.60; 95% confidence interval, 0.38-0.94; P=.022); and recommendation of the allocated intervention to a friend-61 per 110 (73.6%) and 87 per 110 (79.1%) (relative risk, 0.90; 95% confidence interval, 0.80-1.08; P=.341). Other secondary outcomes, including cesarean delivery, were not significantly different. Foley balloon placement for 6 hours for cervical ripening in parous women hastens birth but does not increase maternal satisfaction relative to 12-hour placement. Foley reinsertion for additional ripening was more frequent in the 6-hour group.

Fetal Heart-Rate Variability: Validation of a New Continuous, Noninvasive Computerized Analysis

Objective: We developed a computerized heart-rate variability index related to the fetal parasympathetic activity: the Fetal Stress Index (FSI). The objective was to determine whether the FSI is related to the visual analysis of the fetal heart rate (FHR). Methods: Thirty tracings recorded at a labor ward were classified according to the NICHD categories: (I) normal FHR tracing, (II) intermediate risk of acidosis, and (III) high risk. FSI was calculated as minimum, maximum, and mean, and was evaluated before the onset of the FHR pattern, during the 10 min following, and between 10 and 20 min after that. Results: The FSI for categories II and III was similar to that of category I before the onset of the FHR pattern. FSI min was lower just after the onset of the abnormal FHR in category III, compared with that of category I (33 vs. 43, p < 0.001). Between 10 and 20 min after the onset of the abnormal FHR, we observed a significant reduction in FSI min in categories II and III (44 vs. 39 vs. 29.7, p < 0.0001). Conclusion: Although further studies are necessary for the sake of clinical validation, FSI could constitute an interesting method for the evaluation of fetal well-being.

Increased Intravenous Hydration of Nulliparas in Labor

Maternal hydration can affect labor progression and is critical for fetal well-being. When women have restricted oral fluid intake during labor, the rates of dysfunctional labor and cesarean delivery increase. However, studies have reported conflicting results regarding hydration and its effects on labor duration, incidence of labor dystocia, and adverse maternal and neonatal outcomes. Maternal exhaustion and dehydration from prolonged labor have been linked to a more frequent need for epidural analgesia, cesarean delivery, greater occurrence of maternal or fetal infection, adverse birth outcomes, and postpartum hemorrhage. This randomized clinical trial was designed to compare the effects of oral hydration alone with those of oral and intravenous (IV) hydration on duration of labor, need for oxytocin, and incidence of adverse outcomes due to prolonged labor. Eligible patients, aged 18 to 35 years, were nulliparous, with a singleton pregnancy, in spontaneous active labor, with cervical dilation at 4 to 5 cm, gestational age 38 to 40 weeks, normal fetal heart rate tracings, intact membranes, and cephalic presentation. Labor analgesia was not used. Women were randomly assigned to 1 of 4 groups, with control women in group 1 receiving usual care that did not involve an IV infusion of Ringer’s lactate solution. Patients in groups 2, 3, and 4 received an infusion of Ringer’s lactate solution at the respective rates of 60, 120, and 240 mL/h. All participants were allowed to drink water or soft beverages at will. Infusion pumps controlled the flow of Ringer’s lactate solution allotted to the participants in groups 2, 3, and 4. Total fluid volumes were recorded. Main outcome data were duration of the active phase of the first stage of labor, durations of the second and third stages of labor, need for oxytocin, mode of delivery, Apgar scores at 1 and 5 minutes, and volumes of IV and oral fluids. All collected data were analyzed using SPSS. Means were compared using analysis of variance and proportions by the χ2 test. P < 0.05 was considered significant. Of 120 women recruited, 20 had cesarean deliveries, and 100 delivered vaginally. Maternal age and weight, cervical dilation, and station of the fetus were similar in all 4 groups as were neonatal gestational age at birth, birth weight, Apgar scores at 1 and 5 minutes, and presence of meconium in the amniotic fluid. For women who delivered vaginally, the differences in the duration of the active phase of the first stage of labor were significant (252.3 ± 40.9, 237.8 ± 36.4, 231.7 ± 43.5, and 206.2 ± 38.3 minutes for groups 1–4, respectively; P < 0.001). The differences in the duration of the second stage of labor were also significant between groups: 64.3 ± 13.9, 54.8 ± 16.2, 51.3 ± 11.9, and 49.8 ± 11.4 minutes, respectively (P = 0.01). Differences in duration were not significant (P = 0.58) for the third stage of labor. In group 1, 53.3% of patients needed oxytocin augmentation compared with 20.0% in group 4. The percentages of patients who underwent each mode of delivery did not differ significantly. Eight women in group 1 and 2 women in group 4 had a cesarean delivery because of failure to progress or other complications; differences among the 4 groups were not significant. Three newborns in group 1 and 1 neonate in group 3 had an Apgar score less than 7 at 1 minute, but no infants in groups 2 and 4 had scores less than 7. The 4 groups did not differ in volume of oral fluid intake. The incidence of vomiting was 10%, 13.3%, 3.3%, and 6.6% in groups 1 to 4, respectively. Providing adequate hydration during labor is a major concern for obstetric professionals. Infusing Ringer’s lactate solution significantly reduced the mean duration of active labor. A patient’s self-regulated intake of drink and food during labor can help reduce stress and create a feeling of control. Intravenous hydration administered to nulliparous women in active labor significantly reduced labor duration and the frequency of both prolonged labor and oxytocin administration without increasing the occurrence of adverse effects.

Loss of FHR variability diagnosed by frequency analysis

To determine the loss of fetal heart rate (FHR) baseline variability by frequency analysis. The FHR tracings of 12 normal fetuses and others with various conditions, as well as flat FHR tracings of a late deceleration (LD) and anencephaly recorded with Doppler fetal monitors, were scanned and processed using fast Fourier transform (FFT) analysis. The ratio of the area under the low frequency spectrum divided by the area under the whole spectrum (La/Ta) and the peak power spectrum density (PPSD) were determined. Long-term variability (LTV) measures >10 bpm revealed significantly more La/Ta and PPSD than LTV <10 bpm in normal FHR tracings. The La/Ta and PPSD were >15% and 60 bpm(2)/Hz, respectively, in representative values of normal FHR cases and in those of fetal respiration, hiccupps and non-reactive FHR, whereas those of the flat baseline of LD and anencephaly were <15% and 60 bpm(2)/Hz. Loss of baseline variability is diagnosed when the La/Ta ratio and PPSD are <15% and 60 bpm(2)/Hz, respectively, based on the FFT frequency analysis of the FHR baseline.

Lipid peroxidation and antioxidant activity in patients in labor with nonreassuring fetal status

Objective The aim of our study was to evaluate lipid peroxidation products and antioxidant enzyme activity in placental tissue and umbilical cord blood, as a marker for fetal hypoxia in patients in labor with nonreassuring fetal status. Study design Umbilical cord arterial blood and placental tissue samples were collected from 24 patients with term pregnancies in labor and nonreassuring fetal heart rate (FHR) patterns (study) and 24 women with normal pregnancies in labor and normal FHR tracings (controls) for determination of malondialdehyde (MDA) as a marker for lipid peroxidation and superoxide dismutase (SOD) for the antioxidant activity. Measured values were compared statistically between two groups using independent samples t-test or Mann–Whitney U-test. Results The median 1 min Apgar score was 8 (range 4–9) in the study group and 9 (range 8–10) in the control group, respectively ( p < 0.001). There was no statistically significant difference between study and control groups in terms of mean 5 min Apgar scores ( p > 0.05). Placental MDA levels in patients with nonreassuring fetal status were found to be significantly elevated compared to the control group (12.14 nmol/g tissue versus 9.75 nmol/g tissue; p < 0.01). The placental SOD activity in the study group was significantly higher ( p < 0.01) compared to controls (3.57 U/mg protein versus 2.63 U/mg protein). The umbilical cord blood MDA levels in the study group were higher than in normal pregnancies (4.99 nmol/mL, 3.88 nmol/mL; p < 0.05). The activity of SOD in umbilical cord blood was significantly higher ( p < 0.001) in patients with nonreassuring fetal status when compared with the control group (11.62 versus 6.95 U/mL). Conclusion Lipid peroxidation products and antioxidant functions were elevated in the umbilical cord blood and placenta of patients having nonreassuring FHR tracings during labor. These findings indicate that lipid peroxidation products in placenta and umbilical cord blood can be used as a possible marker for fetal hypoxia during labor and SOD levels may discriminate acute from chronic hypoxia. Further investigations are needed with large number of series to clarify the variations of lipid peroxidation and antioxidant activity due to acute or chronic fetal hypoxia.

Chronobiology of labour pain perception: an observational study

Circadian variation may affect many biological and pharmacological phenomena. To assess circadian variations in labour pain perception, 222 consecutive nulliparous women with uncomplicated pregnancy, spontaneous labour, cervical dilatation (3-5 cm), ruptured membranes and normal fetal heart rate tracings were studied. Visual analogue pain scores (VAPS) were analysed and divided into four periods: night (1:01 a.m. to 7:00 a.m.), morning (7:01 a.m. to 1:00 p.m.), afternoon (1:01 p.m. to 7:00 p.m.) and evening (7:01 p.m. to 1:00 a.m.). VAPS were also compared between daytime (morning+afternoon) and nocturnal (evening+night) periods. Daytime mean VAPS were lower than nocturnal scores [75.6 (15.1) vs 85.7 (14.1), P<0.0001]. VAPS were lower in the morning than in the afternoon, evening and night periods (anova, P<0.0001). Labour pain perception appears to be chronobiological, and this might be taken into account when enrolling parturients in studies designed to assess or treat labour pain.

Lipid peroxidation in umbilical arterial blood at birth: the effects of breech delivery.

To determine oxygen free radical activity in breech presentation at birth and relate it to umbilical cord blood acid-base status. A series of 63 singleton deliveries (28 cephalic deliveries as controls), 23 breech deliveries with normoacidemia, and 12 breech deliveries with mild acidaemia) had determination of malondialdehyde and acid-base parameters. The delivery suite in the Department of Obstetrics and Gynaecology at the Süleyman Demirel University, Isparta, Turkey. Sixty-three singleton infants born at term with spontaneous or induced labour and initially normal fetal heart rate tracing. After delivery, umbilical cord arterial and venous blood samples were collected for the determination of malondialdehyde concentrations. Oxygen saturation, pO2, pCO2, pH, and base excess were also measured. Umbilical cord arterial and venous blood gases and malondialdehyde levels. There was a significant correlation between umbilical arterial and venous levels of malondialdehyde and all acid-base parameters (P < 0.001). There were negative correlations between malondialdehyde levels and pH, pO2 and bicarbonate, while there was a positive correlation between malondialdehyde concentrations and pCO2. A positive correlation between malondialdehyde levels and base excess was present in the control group and total breech group (n = 35). The malondialdehyde levels in the total breech group, nonacidaemic breech group (n = 23) and the mildly acidaemic breech group (n = 12) were significantly higher than those in the control group (P < 0.0001). However, acid-base parameters in the nonacidaemic breech group were not statistically different from those in the control group. Lipid peroxidation products (malondialdehyde) existed to some extent in the umbilical cords of newborns with normal acid-base parameters in breech delivery. Our data support the contention that lipid peroxide may be a more sensitive measure for metabolic dysfunctions due to fetal hypoxia than acid-base balance.

Lipid peroxidation in cord blood: the effect of amniotic fluid volume.

To assess the effect of amniotic fluid volume on umbilical cord arterial lipid peroxide levels in relation to intrapartum events. Prospective observational study. Delivery suite of a teaching hospital, the Chinese University of Hong Kong. Women with singleton, term, cephalic presentation, and an initially normal fetal heart rate tracing. All pregnancies had amniotic fluid index assessments before and after amniotomy and cord arterial lipid peroxide determination at delivery. Multiple regression analysis. Cord arterial malondialdehyde and organic hydroperoxide levels. In 247 cases following amniotomy levels were inversely correlated with intrapartum amniotic fluid index. Amniotic fluid index during labour was an independent determinant of cord arterial lipid peroxide concentration, along with duration of second stage, absence of epidural, presence of tight nuchal cord entanglement and evidence of fetal distress. Oligohydramnios during labour is associated with high levels of lipid peroxidation in the fetus, reflecting an increase in hypoxic cellular damage by free radicals.

The effect of early second stage bradycardia on newborn status

In the present study 45 patients with intrapartum cardiotocograms showing prolonged fetal bradycardia during the early second stage of labor were included. Bradycardia persisted for 180 s or more with either rapid or prolonged return to baseline, without loss of variability and rise of baseline fetal heart rate (FHR). The mean duration of bradycardia was 5.0 ± 1.3 min. In the group with normal FHR tracings the rate of normal delivery (73.3%) was significantly higher than that of the group with fetal bradycardia (26.7%, P < 0.0001). We also noted a significantly higher rate of cesarean section (44.4%) in patients with abnormal FHR tracings, compared to that (11.1%) of parturients with normal FHR tracings ( P < 0.001). In all cases blood samples were obtained from the umbilical cord artery, immediately after delivery. Only in two cases with abnormal FHR tracing umbilical cord artery was the pH less than 7.20. We conclude that in most cases, prolonged fetal bradycardia in the early second stage with the characteristics described above is well tolerated by a mature fetus.

Antepartum and Intrapartum Assessment of the Fetus: Current Status and Does It Influence Outcome?

SUMMARY 1. Electronic fetal monitoring (EFM) can predict fetal hypoxia as defined by low Apgar scores at birth. However, the predictive value is poor in low-risk patients. 2. A normal fetal heart rate tracing is a good predictor of fetal well-being. 3. It is unclear whether EFM can prevent cerebral palsy and mental retardation. 4. Severe perinatal asphyxia, particularly in full-term infants, usually leads to neonatal demise. However, in some cases it can lead to long-term neurological handicap. In such infants, the asphyxia is usually severe and prolonged. It is usually associated with seizures, other abnormal neurological signs in the neonatal period and the long-term handicap probably always involves the motor system. 5. Studies of the aetiology of cerebral palsy and mental retardation have shown that only a small percentage of both can be attributed to perinatal asphyxia.

Intrapartum fetal heart rate monitoring as a predictor of fetal distress and immediate neonatal condition in low-birth weight (≤ 1,800 grams) infants

Among 1,318 live born infants delivered in our institution during a 120-day period, 1,025 (77.8%) were monitored electronically. Of the 1,025 monitored infants, 89 were of low birth weight (less than or equal to 1,800 gm) and were admitted to the neonatal intensive care unit. Twenty-seven (30%) of these had abnormal fetal heart rate tracings. The remaining 62 (70%) had normal fetal heart rate tracings. Of the 27 low-birth weight neonates with an abnormal fetal heart rate tracing, 24 (89%) were asphyxiated, whereas of those 62 low-birth weight infants with a normal fetal heart rate tracing, only nine (14%) had asphyxia (p less than 0.001). Of the 27 low-birth weight neonates with abnormal fetal heart rate tracings, 20 (74%) developed hyaline membrane disease, whereas of the 62 low-birth weight neonates with normal fetal heart rate tracings, 10 (16%) developed hyaline membrane disease (p less than 0.001). The results of this study suggest that electronic fetal monitoring provides a specific and sensitive method for identifying those low-birth weight infants who are at high risk for asphyxia and hyaline membrane disease.

Abnormal fetal heart rate patterns and percentage of creatine phosphokinase-2

Eighteen term newborn infants who had been evaluated by internal fetal heart rate (FHR) monitoring were studied to correlate fetal monitor tracings with Apgar scores and serum creatine phosphokinase-2 (CPK2), the myocardium-specific isoenzyme of CPK. The percentage of CPK2 at 30 ± 6 hours did not correlate significantly with Apgar scores. However, values for the percentage of CPK2 at 30 ± 6 hours were significantly higher in neonates with abnormal FHR tracings than in those with normal FHR tracings (p < 0.01). These preliminary data suggest that subtle intrapartum asphyxial injury may be present without adversely affecting Apgar scores.