Changes In Fetal Heart Rate Patterns Research Articles

Evaluation of fetal acidemia during delivery using the conventional 5-tier classification and Rainbow systems.

The association between prepartum time-series fetal heart rate pattern changes and cord blood gas data at delivery was examined using the conventional 5-tier classification and the Rainbow system for 229 female patients who delivered vaginally. They were classified into three groups based on the results of umbilical cord blood gas analysis at delivery. The fetal heart rate pattern classifications were based on analysis of measurement taken at 10-min intervals, beginning at 120 min pre-delivery. The relationship between fetal heart rate pattern classification and cord blood pH at delivery changed over time. The 5-tier classification at each interval increased before delivery in the Mild and Severe groups compared with the Normal group. No significant differences were observed between acidemia groups. The Rainbow classification showed a significant differences between the acidemia groups at each interval, particularly during the prepartum period. A relationship between classification and outcome was evident before delivery for both the 5-tier classification and Rainbow system.

A randomized controlled trial studying the effect of maternal hyperoxygenation on fetal heart rate in suspected fetal distress

Objective: To investigate the effect of maternal hyperoxygenation on fetal heart rate (FHR) when applied for suspected fetal distress during the second stage of term labor. Approach: A single-center randomized controlled trial was conducted in a tertiary care hospital in The Netherlands. Participants were included during the second stage of labor in case of an intermediary or abnormal FHR pattern. Patients were randomized to receive either 100% oxygen at 10 l/min until delivery, or conventional care without additional oxygen. The primary outcome was the change in FHR pattern before and after the onset of the study, measured as the change in depth and duration of FHR decelerations. Secondary outcome measures were features based on phase-rectified signal averaging (PRSA), baseline assignability, and deceleration characteristics of the FHR pattern. Main results: Between March 2016 and April 2018, 117 women were included. The FHR pattern could be analyzed for 71 participants, the other 46 women delivered before the end of the post time-frame. A 2.3% reduction in depth and duration of FHR decelerations was found after maternal hyperoxygenation, compared to a 10% increase in the control group (p = 0.24). Maternal hyperoxygenation had a significantly positive effect on PRSA metrics, with a decrease in PRSA-acceleration capacity (p = 0.03) and PRSA-deceleration capacity (p = 0.02) in the intervention group compared to the control group. Significance: The difference in depth and duration of decelerations after the start of the study was not significantly different between both study groups. A statistically significant positive effect on PRSA-deceleration capacity and PRSA-acceleration capacity was found after maternal hyperoxygenation, which might be associated with a positive effect on neonatal outcome.

Is short-term-variation of fetal-heart-rate a better predictor of fetal acidaemia in labour? A feasibility study.

Continuous intrapartum fetal monitoring is challenging and its clinical benefits are debated. The project evaluated whether short-term-variation (STV) and other computerised fetal heart rate (FHR) parameters (baseline FHR, long-term-variation, accelerations and decelerations) predicted acidaemia at birth. The aims of the study were to assess the changes in FHR pattern during labour and determine the feasibility of undertaking a definitive trial by reporting the practicalities of using the monitoring device, participant recruitment, data collection and staff training. 200 high-risk women carrying a term singleton, non-anomalous fetus, requiring continuous FHR monitoring in labour were consented to participate from the Jessop Wing maternity unit, Sheffield, UK. The trans-abdominal fetal ECG monitor was placed as per clinical protocol. During the monitoring session, clinicians were blinded to the computerised FHR parameters. We analysed the last hour of the FHR and its ability to predict umbilical arterial blood pH <7.20 using receiver operator characteristics (ROC) curves. Of 200 women, 137 cases were excluded as either the monitor did not work from the onset of labour (n = 30), clinical staff did not return or used the monitor on another patient (n = 37), umbilical cord blood not obtained (n = 25), FHR data not recorded within an hour of birth (n = 34) and other reasons (n = 11). In 63 cases included in the final analysis, the computer-derived FHR parameters did not show significant correlation with umbilical artery cord pH <7.20. Labour was associated with a significant increase in short and long term variation of FHR and number of deceleration (P<0.001). However, baseline FHR decreased significantly before delivery (P<0.001). The project encountered a number of challenges, with learning points crucial to informing the design of a large study to evaluate the potential place of intrapartum computerised FHR parameters, using abdominal fetal ECG monitor before its clinical utility and more widespread adoption can be ascertained.

Evaluation of 3-tier and 5-tier FHR pattern classifications using umbilical blood pH and base excess at delivery

ObjectiveThe relevance between time-series fetal heart rate (FHR) pattern changes during labor and outcomes such as arterial blood gas data at delivery has not been studied. Using 3-tier and 5-tier classification systems, we studied the relationship between time-series FHR pattern changes before delivery and umbilical artery blood gas data at delivery.MethodsThe subjects were 1,909 low-risk women with vaginal delivery (age: 29.1 ± 4.4 years, parity: 1.7 ± 0.8). FHR patterns were classified by a skilled obstetrician based on each 10 min-segment of the last 60 min before delivery from continuous CTG records in an obstetric clinic.ResultsThe relationship between each 10 min-segment FHR pattern classification from 60 minutes before delivery and umbilical artery blood pH and base excess (BE) values at delivery changed with time. In the 3-tier classification, mean pH of Category I group in each 10 min-segment was significantly higher than that of Category II group. For Category I groups in each 10-minute segment, its number decreased and its average pH increased as the delivery time approached. In the 5-tier classification, there was the same tendency. About each level group in 10 min-segment, the higher the level, the lower the blood gas values, and mean pH of higher level groups decreased as the delivery time approached.ConclusionsThe relationship between classifications and outcomes was clear at any time from 60 min before delivery in 3- and 5-tier classifications, and the 5-tier classification was more relevant.

Variations on fetal heart rate variability.

Intrapartum electronic fetal monitoring (EFM) is widely used throughout the developed and developing world. This practice is based on the understanding that fetal heart rate (FHR) is sensitive to hypoxia. During labour, the fetus may be exposed to acute hypoxia during uterine contractions or intrapartum insults, and has well‐established cardiovascular compensatory defence mechanisms, which ideally prevent hypoxic–ischaemic encephalopathy by maintaining perfusion pressure and substrate delivery to essential organs (Giussani et al. 1993). Failure of these compensatory mechanisms results in a progressively worsening metabolic acidosis. Development of severe acidaemia (pH < 7.05) is a key turning point after which fetuses are unable to maintain fetal cardiovascular defence mechanisms and cerebral perfusion, rendering them at risk of asphyxial brain injury (Gunn & Bennet, 2009). Therefore, intrapartum EFM aims to identify, via changes in FHR patterns, fetuses unable to initiate or maintain such compensatory adaptations in response to hypoxia, which become acidotic, and deliver them before they are at risk of asphyxia, severe acidosis, cardiovascular collapse, end organ damage or death.

Jarisch-Herxheimer Reaction Triggered by Group B Streptococcus Intrapartum Antibiotic Prophylaxis

The Jarisch-Herxheimer reaction is an acute systemic event that can occur during the treatment of spirochetal infections. During pregnancy, it can cause signs and symptoms in both the mother and fetus, including fever, tachycardia, uterine contractions, and fetal heart rate pattern changes. A pregnant woman with limited prenatal care presented at 34 weeks of gestation in preterm labor with possible genital herpes. She received ampicillin for group B Streptococcus prophylaxis. Subsequently, she experienced subjective fever and late fetal heart rate decelerations prompting repeat cesarean delivery. Postpartum, her genital lesions were diagnosed as secondary syphilis, and her newborn had congenital syphilis. Beta-lactam antibiotics for group B Streptococcus intrapartum prophylaxis can trigger the Jarisch-Herxhemer reaction in patients with undiagnosed syphilis resulting in unanticipated changes in maternal and fetal well-being.

Changes in antepartum heart rate patterns with progressive deterioration of the fetal condition

In this paper changes in antepartum fetal heart rate (FHR) patterns are described, that occur with progressive deterioration of the fetal condition. The data on the relationship between heart rate patterns and fetal blood gas and pH values are reviewed. A possible rank ordering is presented in which changes in FHR pattern, body movements and blood flow velocity wave form patterns occur with progressive deterioration of the fetal condition. It is concluded that in small-for-date fetuses changes in heart rate and movement patterns are rather late signs of impairment, coinciding with fetal hypoxaemia. In general, heart rate variation falls below the norm at the same time as decelerations occur; there are, however, large inter-fetal differences. In general, abnormal Doppler velocity wave form patterns precede the occurrence of heart rate decelerations. Their impact on the timing of delivery is, however, still uncertain. The advantages of a numerical analysis of FHR patterns include identification of fetuses with low FHR variation, precision of the actual fetal condition and (at early gestation) longitudinal follow-up of fetuses with abnormal heart rate patterns.

Fetal response to maternal anxiety: a factor in antepartum heart rate monitoring

SummaryWomen in late pregnancy were subjected to mild psychological stress by listening, through headphones, to a prerecorded sequence of sounds which included that of a baby crying. Maternal reaction was detected using maternal heart rate and maternal skin resistance. Coincidental changes were observed in fetal heart rate patterns. Fetal heart rate pattern changes similar to those induced by the tape-recorded sounds have been observed during ‘non-stressed’ antepartum monitoring when patients were disturbed by sounds significant to them.