Severe Variable Decelerations Research Articles

Intrapartum electronic fetal monitoring and perinatal outcomes: Analysis of components of fetal heart rate pattern

Aim: The aim of this study was to assess the components of cardiotocography (CTG) during labor to identify the variables associated with the risk of adverse perinatal outcomes and to ascertain the mode of delivery in these women. Materials and Methods: This prospective observational study included 191 women at term with singleton pregnancy in labor. The CTG findings including baseline heart rate, accelerations, beat-to-beat variability, and type and severity of decelerations were noted as per the International Federation of Gynecology and Obstetrics classification and grouped into Category II or III patterns as per the National Institute of Child Health and Human Development classification. Low APGAR score, cord PH <7, neonatal intensive care unit admission, respiratory distress, and hypoxic-ischemic encephalopathy were considered adverse neonatal outcomes. Results: Persistent fetal tachycardia, poor beat-to-beat variability, and severe variable deceleration showed a significant association with adverse neonatal outcome and delivery by cesarean section (P < 0.05). Adverse neonatal outcomes were noted in 4.2% of babies and 40.9% of babies born to mothers whose CTG was categorized as II and III patterns, respectively (P < 0.001). Birth by cesarean section was significantly different between those with Category II and Category III patterns, 33.7% and 65.4%, respectively (P < 0.01). Conclusion: Reduction in the beat-to-beat variability and presence of severe variable decelerations are independent risks for adverse neonatal outcomes, irrespective of the category of CTG pattern. Category III fetal heart rate pattern shows a significant association with adverse outcomes and risk of cesarean delivery. Grading the Category II patterns may help in identifying variables that are truly associated with acidemia and further research into this is recommended.

Interobserver agreement in analysis of cardiotocograms recorded during trial of labor after cesarean

Introduction: To examine interobserver agreement in intrapartum cardiotocography (CTG) classification in women undergoing trial of labor after a cesarean section (TOLAC) at term with or without complete uterine rupture.Materials and methods: Nineteen blinded and independent Danish obstetricians assessed CTG tracings from 47 women (174 individual pages) with a complete uterine rupture during TOLAC and 37 women (133 individual pages) with no uterine rupture during TOLAC. Individual pages with CTG tracings lasting at least 20 min were evaluated by three different assessors and counted as an individual case. The tracings were analyzed according to the modified version of the Federation of Gynaecology and Obstetrics (FIGO) guidelines elaborated for the use of STAN (ST-analysis). Occurrence of defined abnormalities was recorded and the tracings were classified as normal, suspicious, pathological, or preterminal. The interobserver agreement was evaluated using Fleiss’ kappa.Results: Agreement on classification of a preterminal CTG was almost perfect. The interobserver agreement on normal, suspicious or pathological CTG was moderate to substantial. Regarding the presence of severe variable decelerations, the agreement was moderate. No statistical difference was found in the interobserver agreement between classification of tracings from women undergoing TOLAC with and without complete uterine rupture.Conclusions: The interobserver agreement on classification of CTG tracings from high-risk deliveries during TOLAC is best for assessment of a preterminal CTG and the poorest for the identification of severe variable decelerations.

293: Term appropriate for gestational age infants with Neonatal Encephalopathy: Is there a characteristic intrapartum fetal heart rate pattern?

Neonatal encephalopathy (NE) of the term AGA newborn is source of severe neurological morbidity. Strict criteria for therapeutic Hypothermia (Hth) eligibility enables consistency in diagnosis of NE. We aimed to evaluate intrapartum fetal heart rate patterns in NE eligible for Hth. A retrospective cohort of clinical data and FHR of term AGA infants treated by Hth; computerized records in a tertiary center, 2009 - 2017. Entry criteria for Hth: GA ≥ 36+0w and two obligatory conditions: Bundle (1) 10’ Apgar ≤ 5, CPR > 10’, pH<7.0, BE>16 mEq/ml in cord blood. Bundle (2): altered consciousness and one of the following: hypotonia, decreased reflexes, clinical seizures. FHR 1h prior to delivery was assessed by trained obstetrician. We characterized the pattern of the FHR: Category system (1-3), FHR-NICHD criteria, mean total deceleration area (area = Half of depth x Duration of deceleration, added over given time), mean deceleration duration 50 infants filled the criteria, 30 had recorded antenatal FHR for at least an hour prior to delivery. Overall, group characteristics were: mean maternal age 28.4y±6.04, GA 39w±1.77, parity 2.94±2.44, BW 3136gr±480.34, cord pH 6.9±0.227. Groups with vs without recorded FHR were similar, including the rate of sentinel events such as uterine rupture, placental abruption, heavy meconium (Table). Notably, two third of cases (58%) in both groups were preceded by such a sentinel event. FHR characteristics were: reduced variability 43.3%, terminal bradycardia 50%, tachycardia 40%. Mean area of deceleration 29.06±24.30 and mean duration of deceleration 1.736±1.105. 21 (70%) infants with FHR Category 2 and 9 (30%) Category 3. We compared FHR characteristics of Category 2 vs 3 (not inherent to definitions), respectively: baseline and total number of variable decelerations were significantly different between the groups mean baseline 147bpm±12.18 and 157.77bpm±12.01, p=0.038, total number of variable decelerations 17.23±11.67 and 6.22±4.29, p=0.012. FHR patterns between these two categories were similar for bradycardia, number of severe variable or late decelerations, mean area and mean duration of deceleration Term AGA infants affected by NE have no preceding pathognomonic intrapartum FHR tracing. The majority of NE are determined by unforeseen sentinel events

Relationship between fetal heart rate patterns and a time course for evaluation of fetal well-being: “the 30 minutes rule” for decision of mechanical delivery

ObjectiveTo predict acidosis in fetus showing deceleration associated with non-reassuring fetal status during delivery, we examined the relationship between duration of the deceleration and umbilical arterial pH. Materials and methodsA total of 19,907 deliveries in eight facilities of the Juntendo Perinatal Care Group, 895 cases of vaginal deliveries with level 3 decelerations were selected for the subjects of this study. The cut-off point of time when the umbilical arterial pH fell below 7.20 in all cases of level 3 and for each deceleration type were examined. The explanatory variables were the pH and pO2 of umbilical arterial gas and the time from onset of the level 3 pattern to delivery. From receiver operating characteristic (ROC) analysis using these variables, the critical point indicating low Apgar score was set at an umbilical arterial pH < 7.20. ResultsThe cut-off point of time when the umbilical arterial pH fell below 7.2 was 33.5 min for all cases of level 3, and 604 cases of severe variable decelerations with normal baseline variability and normal baseline heart rates, the cut-off point was 33.5 min as well. For 108 cases of late decelerations, there was no significant cut-off point for either the mild or severe cases. Mild prolonged deceleration showed the cut-off point of 34.5 min. ConclusionsWe confirmed the time indices for predicting and preventing acidosis in fetuses showing decelerations. To prevent fetal acidosis, the decision related to proper timing for performing assisted delivery by considering the time course is important.

Reliability in cardiotocography interpretation - impact of extended on-site education in addition to web-based learning: an observational study.

Previous studies have shown poor reproducibility in cardiotocography (CTG) interpretation. Studies evaluating the Swedish web-based CTG-education program have not proven to increase accurate CTG assessments. The aim of this study was to evaluate whether an extended education can improve inter- and intra-observer reliability in CTG interpretation. Six obstetricians from two different departments interpreted 106 CTG tracings on two occasions. Both departments used a Swedish national web-based CTG education and test for training. One department had, in addition, an extended education program consisting of on-site lectures and oral examinations. Inter- and intra-observer agreements were calculated by simple or weighted kappa (κ) values for the five parameters assessed on CTG. In both departments inter-observer and intra-observer κ showed moderate to excellent agreement (ranges for κ 0.41-0.76 and 0.65-0.93, respectively). Obstetricians at the department with extended CTG education had better inter-observer reliability for variability and accelerations. This was also the case for intra-observer reliability with the addition of baseline frequency. Both inter- and intra-observer agreement increased from moderate to substantial in both departments when decelerations were dichotomized into harmless (including early and simple variable decelerations) or hypoxic (including late, severe variable, prolonged and combined decelerations) (κ 0.63-0.78) compared with the current sub-classification of decelerations (κ 0.42-0.65). Agreement in CTG interpretation was better than expected in both departments, especially when divided into harmless/hypoxic changes. Combination of different learning methods (web-based, on-site lectures and case discussion) might result in a better CTG interpretation agreement compared with web-based learning solely.

Can Intrapartum Cardiotocography Predict Uterine Rupture among Women with Prior Caesarean Delivery?: A Population Based Case-Control Study.

ObjectiveTo compare cardiotocographic abnormalities recorded during labour in women with prior caesarean delivery (CD) and complete uterine rupture with those recorded in controls with prior CD without uterine rupture.Study DesignWomen with complete uterine rupture during labour between 1997 and 2008 were identified in the Danish Medical Birth Registry (n = 181). Cases were validated by review of medical records and 53 cases with prior CD, trial of labour, available cardiotocogram (CTG) and complete uterine rupture were included and compared with 43 controls with prior CD, trial of labour and available CTG. The CTG tracings were assessed by 19 independent experts divided into groups of three different experts for each tracing. The assessors were blinded to group, outcome and clinical data. They analyzed occurrence of defined abnormalities and classified the traces as normal, suspicious, pathological or pre-terminal according to international guidelines (FIGO).ResultsA pathological CTG during the first stage of labour was present in 77% of cases and in 53% of the controls (OR 2.58 [CI: 0.96–6.94] P = 0.066). Fetal tachycardia was more frequent in cases with uterine rupture (OR 2.50 [CI: 1.0–6.26] P = 0.053). Significantly more cases showed more than 10 severe variable decelerations compared with controls (OR 22 [CI: 1.54–314.2] P = 0.022). Uterine tachysystole was not correlated with the presence of uterine rupture.ConclusionA pathological cardiotocogram should lead to particular attention on threatening uterine rupture but cannot be considered a strong predictor as it is common in all women with trial of labour after caesarean delivery.

Accelerated acidosis in response to variable fetal heart rate decelerations in chronically hypoxic ovine fetuses

Due to limitations of technology, clinicians are typically unable to determine if human fetuses are normoxic or moderately, chronically hypoxic. Risk factors for chronic hypoxia include fetal growth restriction, which is associated with an increased incidence of oligohydramnios and thus a risk for umbilical cord occlusion (UCO) and variable fetal heart rate (FHR) decelerations. At delivery, fetal growth restriction infants (<3rd percentile) have nearly twice the incidence of low Apgar scores and umbilical pH <7.0. Despite the risks of oligohydramnios and intermittent UCO, there is little understanding of the acid/base responses rates of chronically hypoxic fetuses to variable FHR decelerations as might occur during human labor. We sought to compare the increase in base deficit (BD) among chronically hypoxic as compared to normoxic ovine fetuses in response to simulated mild, moderate, and severe variable FHR decelerations. Near-term ovine fetuses were chronically prepared with brachial artery catheters and an inflatable umbilical cuff occluder. Following a recovery period, normoxic (n = 9) and spontaneously hypoxic (n = 5) fetuses were identified (arterial O2 saturation ≤55%). Both animal groups underwent graded, 1-minute occlusions every 2.5 minutes with 1 hour of mild (∼30 beats/min [bpm] decrease from baseline), 1 hour of moderate (∼60 bpm decrease from baseline), and up to 2 hours of severe (∼90 bpm decrease from baseline) variable FHR decelerations until fetal arterial pH reached 7.00, when occlusions were stopped. Repetitive UCO resulted in development of acidosis (pH <7.0) in both groups. Hypoxic and normoxic fetuses demonstrated similar BD increases in response to both mild (0.39, interquartile range [IQR] 0.28-0.45 vs 0.26, IQR 0.01-0.30 mEq/L/10 min, P = .25) and severe (1.97, IQR 1.50-2.43 vs 1.51, IQR 0.97-2.45 mEq/L/10 min, P = .63) variable decelerations. However, moderate variable decelerations increased BD in hypoxic fetuses at 2.5 times the rate of normoxic fetuses (0.97, IQR 0.52-1.72 vs 0.39, IQR 0.23-0.47 mEq/L/10 min, P = .03). During the recovery period, hypoxic fetuses cleared BD slower than normoxic fetuses (0.08 ± 0.02 vs 0.12 ± 0.03 mEq/L/min, P = .02). In comparison to normoxic fetuses, hypoxic fetuses can more rapidly progress to significant metabolic acidosis in response to moderate FHR variable decelerations, and more slowly recover with in utero resuscitation, likely a consequence of impaired placental function and fetal physiologic responses.

Acute Fetal Asphyxia After Gastric Rupture in a Pregnant Patient With a Gastric Band

We report a 37-year-old primigravida with a gastric band who developed the clinical picture of abdominal pain, vomiting and regurgitation coexistent with a cardiotocogram with severe variable decelerations with absent variability at 33 weeks' gestation. After partial improvement with gastric band enlargement, new aggravation of symptoms and recurrence of a pathological cardiotocogram led to an emergency cesarean section. Intraoperatively, hemoperitoneum from gastric rupture was verified and partial gastrectomy was performed. After bariatric surgery, pregnant women are at increased risk of gastrointestinal complications, which may need prompt and multidisciplinary diagnosis and management in order to avoid maternal-fetal morbidity and mortality.

Cardiotocography patterns and risk of intrapartum fetal acidemia.

To identify cardiotocography (CTG) patterns associated with increased risk of intrapartum fetal acidemia. A prospective observational cohort study of 1070 women with fetal scalp blood sampling (FBS) during labor was conducted at Karolinska University Hospital, Stockholm, Sweden. Women with a nonreassuring CTG pattern underwent FBS, and lactate concentration was measured at the bedside. Lactate concentrations >4.8 mmol/L were defined as fetal acidemia. A senior obstetrician, blinded to the lactate concentration at FBS, visually interpreted the CTG tracings that had prompted FBS. There were 2134 FBSs performed on 1070 laboring women, constituting 11% of all deliveries at this labor ward. The CTG patterns with the highest frequency of lactacidemia at FBS were late or severe variable decelerations combined with tachycardia (20%-25% at first FBS and 33%-49% at last FBS). With a normal baseline fetal heart rate, normal variability, and absence of serious decelerations, the fetal scalp blood lactate concentration at the first FBS was normal in 97.5% of cases. The group with isolated reduced variability had no increased prevalence of acidemia and median lactate concentration did not differ from the normal group. Isolated reduced variability is in most cases not a sign of hypoxia. If development of hypoxia is ruled out with one FBS, this pattern does not require monitoring with repetitive FBSs throughout labor. Late decelerations and severe variable decelerations increase the risk for intrapartum fetal metabolic acidemia to the same extent. The combination of these decelerations and tachycardia was associated with the highest rate of fetal metabolic acidemia.

Legal Briefs: Iatrogenesis: Prolapsed Umbilical Cord After Artificial Rupture of the Membranes and Unskilled Stabilization

* Abbreviations: AROM, : artificial rupture of the membrane ETT, : endotracheal tube FP, : family practitioner HR, : heart rate PPHN, : pulmonary hypertension of the newborn PPV, : positive pressure ventilation A 3,530-g term infant was delivered to a 22-year-old G1P0 mother who had an unremarkable prenatal course. She smoked during pregnancy and had a placenta previa that resolved by mid-gestation. A family practitioner (FP) was the treating physician during pregnancy. He decided at 39 1/2 weeks’ gestation to induce because of “uterine irritability.” When asked during the deposition why he induced labor, he said that the mother complained of abdominal discomfort, and she was at high risk because of her smoking. The plaintiff obstetrician was critical of the decision to induce because a valid reason was lacking, in his opinion. The defense obstetrician countered by saying 39 weeks is an acceptable gestation to induce. The plaintiff obstetrician said it was very unlikely that a successful induction would occur because the mother was a prima gravida, the fetus was large, and the cervix was unfavorable. Induction was by dinoprostone, followed by oxytocin (Pitocin®, JHP Pharmaceuticals, LLC, Rochester, MI) augmentation. When the cervix was 70% effaced and 2 cm dilated, and the fetus was at a −2 station, the FP decided to rupture the membranes. A few minutes after artificial rupture of the membranes (AROMs), multiple severe variable decelerations occurred, and 8 minutes after AROMs a prolapsed cord was discovered; the fetal heart rate (HR) became 50 beats per minute. The plaintiff obstetrician was critical of the decision to rupture the membranes because the fetal head was not engaged. The FP defendant said that the head was “well applied” to the cervix. The defense obstetrician said that because the FP said the head was well applied to the cervix, it was within standard of care to perform AROM even if the head was not technically engaged. All agreed that engagement of the head meant that in cephalic presentations …

Acute fetal asphyxia after gastric rupture in a pregnant patient with a gastric band

We report a 37-year-old primigravida with a gastric band who developed the clinical picture of abdominal pain, vomiting and regurgitation coexistent with a cardiotocogram with severe variable decelerations with absent variability at 33 weeks' gestation. After partial improvement with gastric band enlargement, new aggravation of symptoms and recurrence of a pathological cardiotocogram led to an emergency cesarean section. Intraoperatively, hemoperitoneum from gastric rupture was verified and partial gastrectomy was performed. After bariatric surgery, pregnant women are at increased risk of gastrointestinal complications, which may need prompt and multidisciplinary diagnosis and management in order to avoid maternal-fetal morbidity and mortality.

Acidemia at birth in the vigorous infant as a trigger incident to assess intrapartum care with regard to CTG patterns

Objective: To evaluate if acidemia in vigorous infants is a useful variable in the assessement of intrapartm care with regard to cardiotocographic (CTG) patterns during the second stage.Methods: Cases (n = 241) were infants with an umbilical artery pH < 7.05, controls (n = 482) were infants with pH ≥ 7.05. Apgar score was ≥7 at 5 min in both groups. CTGs during the last two hours of labor were assessed and neonatal outcomes compared. A sub-analysis of cases with metabolic acidemia: pH < 7.00 and base deficit ≥12 mmol/L and acidemia: 7.00 < pH < 7.05 was performed.Results: 63% of cases had a pathological CTG versus 26% of controls (p < 0.001). Patterns with severe variable decelerations had a significantly longer duration in cases. Metabolic acidemia was significantly associated with severe variable decelerations and decreased variability. Infants to cases were admitted to neonatal care in 19% versus 2% of controls (p < 0.001). With metabolic acidemia, 32% were admitted.Conclusion: An umbilical artery pH < 7.05 at birth of vigorous infants may be a useful variable for quality control of intrapartum management with regard to the assessment of second-stage CTGs. Differences in duration of pathological patterns indicate passiveness in acidemic cases.

Correlation of arterial fetal base deficit and lactate changes with severity of variable heart rate decelerations in the near-term ovine fetus

Recent guidelines classify variable decelerations without detail as to degree of depth. We hypothesized that variable deceleration severity is highly correlated with fetal base deficit accumulation. Seven near-term fetal sheep underwent a series of graded umbilical cord occlusions resulting in mild (30 bpm decrease), moderate (60 bpm decrease), or severe (decrease of 90 bpm to baseline <70 bpm) variable decelerations at 2.5 minute intervals. Mild, moderate, and severe variable decelerations increased fetal base deficit (0.21 ± 0.03, 0.27 ± 0.03, and 0.54 ± 0.09 mEq/L per minute) in direct proportion to severity. During recovery, fetal base deficit cleared at 0.12 mEq/L per minute. In this model, ovine fetuses can tolerate repetitive mild and moderate variable decelerations with minimal change in base deficit and lactate. In contrast, repetitive severe variable decelerations may result in significant base deficit increases, dependent on frequency. Modified guideline differentiation of mild/moderate vs severe variable decelerations may aid in the interpretation of fetal heart rate tracings and optimization of clinical management paradigms.

Correlation research on the embryo heart monitoring variable deceleration and the umbilical cord entangle the neck pregnant woman body posture change

Objective To explore the correlation between the embryo heart monitoring variable deceleration (VD) and the umbilical cord entangle the neck pregnant woman body posture changes.Methods 316 cases of 36 w pregnant women with fetus heart rate monitoring (i.e.embryo to supervise) and the VD were randomly divide into two groups,those with left side decubitus embryo heart monitoring still having the VD,166patients adopted half decubitus or right flank position as the observation group,other 150 pregnant women who carried on the embryo heart monitoring by only left side decubitus were selected as the control group.Embryo heart monitoring diagram of curves and B ultra sieves were observed in two groups to find out the belt to entangle the neck example number,the childbirth way and encircles produced the situation.Results The observation group and the control group were compared,the normal graph formation rate increased,the mild variable deceleration (MVD),the severe variable deceleration (SVD),the umbilical cord entangles the neck formation rate reduced,the fetal distress,the newborn suffocates rate decreased(P＜ 0.01); there was no significant difference in the childbirth way.Conclusion Left side decubitus embryo heart monitoring could make the pregnant women with VD,change their body postures,restore the embryo heart monitoring curve normally,relieve the umbilical cord oppression,even cause the winding umbilical cord to loosen,reduce the fetal distress newborn suffocate rate. Key words: Embryo heart monitoring; Variable deceleration; The umbilical cord entangles the neck; Body posture change

Strip of the Month: August 2012

Strip of the Month: August 2012

Fetal heart rate patterns related to neonatal brain damage and neonatal death in placental abruption

The aim of this study was to determine the correlation between non-reassuring fetal heart rate (NRFHR) patterns and poor neonatal outcome in placental abruption. A retrospective study was performed involving 83 placental abruptions with a live fetus at one tertiary and one secondary hospital in Miyazaki prefecture, Japan. We examined the correlation among NRFHR, umbilical arterial blood gas status, and neonatal poor outcomes, including neonatal death (ND) and cerebral palsy (CP). A total of 83 cases were divided into bradycardia (n=27), recurrent late deceleration (rLD, n=29), severe variable deceleration or prolonged deceleration (sVD/PD, n=8), and other cases (n=19). In the bradycardia group, the incidence of low umbilical artery (UA) pH (<7.0) was 59% and the average UA pH was 6.96±0.22. Among these cases, 10 showed severe bradycardia (less than 80 b.p.m.) and an average UA pH of 6.85±0.24, and four cases resulted in poor outcome (three CP and one ND). In the rLD group, the incidence of low UA pH (<7.0) was 7% and the average UA pH was 7.24±0.12. In this group, a 40-week-old fetus with umbilical phlebitis had a lower UA pH (6.92) and developed CP. In the sVD/PD group, there were no cases of a low UA pH (<7.0) and the average UA pH was 7.30±0.04. In this group, a 31-week-old boy with a UA pH of 7.36 developed CP (PVL). The remaining 19 cases had no CP. Poor neonatal outcome of placental abruption is closely related to NRFHR, especially the degree of bradycardia. In the rLD and sVD/PD groups, risk factors, such as prematurity and fetal inflammation, co-existed.

Severe variable deceleration is associated with intestinal perforation in infants born at 22–27 weeks' gestation

Objective. Intestinal perforation in extremely premature infants is an important cause of death. The aim of the study was to identify fetal heart rate patterns, which were associated with intestinal perforation.Methods. A retrospective cohort study was performed in 92 women who delivered at 22–27 weeks' gestation at a tertiary center in Miyazaki. They delivered 74 singletons, 17 twins and one triplet. Intrapartum fetal heart rate monitoring charts of at least 2-h were examined. Intestinal perforation was diagnosed by the clinical manifestations and operative findings. Multiple logistic regression analysis was used to compare between intestinal perforation group and non-perforation group.Results. Of the 111 neonates, 17 had intestinal perforation. Severe variable deceleration (p < 0.05), prematurity (p < 0.05), postnatal corticosteroid (p < 0.05), intraventricular hemorrhage of grade III or IV (p < 0.01) and poor survival (p < 0.05) were more frequent in infants with perforation than in the 94 without perforation. Multivariate analysis adjusted for the other risk factors revealed that only severe variable deceleration remained as a risk factor: (odds ratio 3.7; 95% CI 1.1–12.1; p = 0.03).Conclusions. Intrapartum severe variable deceleration is associated with subsequent intestinal perforation in extremely premature infants, suggesting that preventing prolonged periods of these decelerations may prevent intestinal perforation.

Abnormal fetal heart rate tracing patterns in patients with thick meconium staining of the amniotic fluid: association with perinatal outcomes

The objective of the study was to evaluate, in labors complicated by thick meconium-stained amniotic fluid, the association between specific fetal heart rate (FHR) patterns and adverse perinatal outcomes. A retrospective cohort study of patients with FHR tracing data (n = 1638) from a previously reported randomized controlled trial of amnioinfusion for the prevention of meconium aspiration syndrome. The presence of FHR tracing abnormalities was associated with an increased risk of perinatal mortality and/or neonatal morbidity (moderately abnormal: adjusted odds ratio [OR], 1.67; 95% confidence interval [CI], 1.18-2.37; markedly abnormal: adjusted OR, 2.97; 95% CI, 1.88-4.67). Specific abnormalities that were associated with the risk of perinatal mortality and/or neonatal morbidity included prolonged decelerations (OR, 1.22; 95% CI, 1.02-1.48), severe variable decelerations (OR, 1.08; 95% CI, 1.00-1.16), bradycardia (OR, 2.49; 95% CI, 1.02-6.11), and tachycardia (OR, 2.43; 95% CI, 1.49-3.94). The presence of abnormal FHR tracing patterns in meconium-stained amniotic fluid patients is associated with an increased risk of adverse perinatal outcomes.

Measures of acidosis with repetitive umbilical cord occlusions leading to fetal asphyxia in the near-term ovine fetus

Increasing frequency of severe variable decelerations is associated with acidemia. However, there is little understanding of its development or normalization rate. To quantify the time course of acidemia, 10 near-term fetal sheep underwent a series of mild (1 minute every 5 minutes), moderate (1 minute every 3 minutes), and severe (1 minute every 2 minutes) umbilical cord occlusions (UCO), lasting 1 hour each or until fetal arterial pH decreased to less than 7.00. Each minute of UCO resulted in base deficit (BD) and lactate increases at rates of 0.56 and 0.35 mmol/L per minute, respectively. During a 2 h recovery, BD and lactate normalized at rates of 0.09 and 0.04 mmol/L per minute. BD correlated highly with lactate (r = 0.95; P < .001). Our findings in the near-term ovine fetus suggest that the knowledge of fetal BD deterioration and recovery rates can aid assessing fetal acidemia during labor.

Clinical Application of Pulse Transit Time and Correlation With Intrapartum Fetal Heart Rate Monitoring: A Preliminary Study of 18 Full-Term Infants

The authors show that pulse transit time and blood pressure are reciprocal in fetal goat models. They applied this technique in clinical settings to correlate changes in pulse transit time with fetal heart rate monitoring patterns and acid-base status. In 18 uncomplicated pregnancies, pulse transit time was obtained from electrocardiograms to pulse oximeter waveform and averaged during each baseline period, defined by the interpretation of fetal heart rate monitoring. According to a > 10% change from the control value, chronological changes were categorized into shortened, unchanged, and prolonged. Pulse transit time was available in 82% +/- 11% of the recordings. In 15 fetuses, 2 (13%) showed prolonged, 7 (47%) showed shortened, and 6 (40%) showed unchanged conditions. Comparisons of the shortened and unchanged categories revealed that severe variable deceleration was significantly increased, and half or more fetuses showed hypoxemia in the shortened category. Shortening of pulse transit time, theoretically indicating a hypertensive condition, was more frequently associated with severe variable decelerations, suggesting that the pulse transit time may supplement the interpretation of fetal heart rate monitoring.