Fetal Heart Rate Variability Research Articles

Maternal metabolism in the fasting state and fetal cardiac activity

The development of the fetal autonomous nervous system (ANS) can be investigated by heart rate variability (HRV) measured by biomagnetic sensors. We recently showed that fetal HRV is altered after a glucose load in mothers with gestational diabetes. However the effect of maternal metabolism and weight development of the mother on fetal HRV is largely unknown.

An antenatal marker of neurodevelopmental outcomes in infants with congenital heart disease

ObjectivePrenatal exposures are known to alter fetal neurodevelopment and autonomic control. We aimed to explore the correlation between fetal autonomic activity, measured by fetal heart rate variability, and 18-month developmental outcome in subjects with congenital heart disease.Study DesignFrom 2010–2013, 5 fetuses with hypoplastic left heart syndrome, 9 with transposition of the great arteries, and 9 with tetralogy of Fallot were included in this prospective cohort study. A maternal abdominal fetal electrocardiogram monitor recorded fetal heart rate at 34–38 weeks gestational age. We assessed associations between fetal heart rate parameters including interquartile range and standard deviation of the fetal RR intervals and 18-month Bayley Scales of Infant Development III scores using Pearson’s correlation coefficient. Multivariable regression modeling identified predictors of neurodevelopmental scores.ResultsFetal heart rate variability parameters at 34–38 weeks gestational age correlated with 18-month Cognition (r=0.47, p=0.03) and Motor scores (r=0.66, p=0.001). The interquartile range of the fetal RR intervals predicted Cognition (β=0.462, p=0.028, R2=0.282) and Motor (β=0.637, p<0.001, R2=0.542) scores.ConclusionsIn fetuses with congenital heart disease, low heart rate variability at 34–38 weeks gestational age predicts diminished 18-month cognitive and motor performance. Prenatal autonomic activity may serve as a marker of early childhood development in these high-risk patients.

Simulation of fetal heart rate variability with a mathematical model

In the clinic, the cardiotocogram (CTG), the combined registration of fetal heart rate (FHR) and uterine contractions, is used to predict fetal well-being. Amongst others, fetal heart rate variability (FHRV) is an important indicator of fetal distress. In this study we add FHRV to our previously developed CTG simulation model, in order to improve its use as a research and educational tool.We implemented three sources of variability by applying either 1/f or white noise to the peripheral vascular resistance, baroreceptor output, or efferent vagal signal. Simulated FHR tracings were evaluated by visual inspection and spectral analysis.All power spectra showed a 1/f character, irrespective of noise type and source. The clinically observed peak near 0.1 Hz was only obtained by applying white noise to the different sources of variability. Similar power spectra were found when peripheral vascular resistance or baroreceptor output was used as source of variability. Sympathetic control predominantly influenced the low frequency power, while vagal control influenced both low and high frequency power. In contrast to clinical data, model results did not show an increase of FHRV during FHR decelerations. Still, addition of FHRV improves the applicability of the model as an educational and research tool.

The hemodynamic repercussions of the autonomic modulations in growth-restricted fetuses

ObjectivesIdiopathic fetal growth restriction is considered to be associated with hemodynamic abnormalities.The study was aimed to the investigation of the relationship between fetal and maternal autonomic balance, arterial and venous hemodynamic Doppler indices and CTG variables in case of normal fetal development and fetal growth restriction. Methods106 patients at 32–40weeks of gestation were enrolled in the study. 30 of them had healthy pregnancy and were involved in Group I. In Group II, 44 pregnant women with fetal growth restriction and normal umbilical hemodynamic Doppler indices were observed. 32 patients with fetal growth restriction and an absent or reversed end-diastolic umbilical flow were monitored in Group III. The curves of maximum blood flow velocity were isolated and their spectral components were determined from the umbilical Doppler spectrograms. The maternal and fetal heart rate variability, conventional CTG patterns were obtained from RR-interval time series registered from maternal abdominal wall electrocardiographically. ResultsThe increased adrenergic regulation has modulated parasympathetic impact on fetal cardiovascular system. The decreased reactivity was mirrored in low LTV, lack of accelerations and an increased score of decelerations.The CTG findings were also featured by the revealed correlations demonstrated an obvious relationship between fetal and maternal hemodynamics in healthy pregnancy. It was possible to speculate that a controlling signal of 0.5Hzhas played a significant role in the umbilical venous blood flow. The decreased fetal autonomic tone and the fetal and maternal hemodynamic decoupling were found in growth-retarded fetuses. ConclusionFetal heart rate pattern was influenced by maternal and fetal autonomic tone. Maternal cardiovascular oscillations were reflected in the umbilical circulation in healthy pregnancy Fetal distress was featured by sympathetic overactivity and the reduction of vagal tone. Such autonomic modulations was manifested by the decelerative pattern of CTG and deteriorated umbilical hemodynamics.

Critical Imperative for the Reform of British Interpretation of Fetal Heart Rate Decelerations: Analysis of FIGO and NICE Guidelines, Post-Truth Foundations, Cognitive Fallacies, Myths and Occam's Razor.

Cardiotocography (CTG) has disappointingly failed to show good predictability for fetal acidemia or neonatal outcomes in several large studies. A complete rethink of CTG interpretation will not be out of place. Fetal heart rate (FHR) decelerations are the most common deviations, benign as well as manifestation of impending fetal hypoxemia/acidemia, much more commonly than FHR baseline or variability. Their specific nomenclature is important (center-stage) because it provides the basic concepts and framework on which the complex “pattern recognition” of CTG interpretation by clinicians depends. Unfortunately, the discrimination of FHR decelerations seems to be muddled since the British obstetrics adopted the concept of vast majority of FHR decelerations being “variable” (cord-compression). With proliferation of confusing waveform criteria, “atypical variables” became the commonest cause of suspicious/pathological CTG. However, National Institute for Health and Care Excellence (NICE) (2014) had to disband the “typical” and “atypical” terminology because of flawed classifying criteria. This analytical review makes a strong case that there are major and fundamental framing and confirmation fallacies (not just biases) in interpretation of FHR decelerations by NICE (2014) and International Federation of Gynecology and Obstetrics (FIGO) (2015), probably the biggest in modern medicine. This “post-truth” approach is incompatible with scientific practice. Moreover, it amounts to setting oneself for failure. The inertia to change could be best described as “backfire effect”. There is abundant evidence that head-compression (and other non-hypoxic mediators) causes rapid rather than shallow/gradual decelerations. Currently, the vast majority of decelerations are attributed to unproven cord compression underpinned by flawed disproven pathophysiological hypotheses. Their further discrimination based on abstract, random, trial and error criteria remains unresolved suggesting a false premise to begin with. This is not surprising considering that the commonest pathophysiology of intrapartum hypoxemia is contraction-induced reduction in uteroplacental perfusion (sometimes already compromised) and not cord compression at all. This distorted categorization causes confusion, false-alarm fatigue and difficulty in focusing on real pathological decelerations making CTG interpretation dysfunctional ultimately compromising patient safety. Obstetricians/midwives should demand reverting to the previous more scientific British categorization of decelerations based solely on time relationship to contractions as advocated by the pioneers like Hon and Caldeyro-Barcia, rather than accepting the current “post-truth” scenario.

Gestational diabetes alters the fetal heart rate variability during an oral glucose tolerance test: a fetal magnetocardiography study

Gestational diabetes mellitus (GDM) potentially harms the child before birth. We previously found GDM to be associated with developmental changes in the central nervous system. We now hypothesise that GDM may also impact on the fetal autonomic nervous system under metabolic stress like an oral glucose tolerance test (OGTT). We measured heart rate variability (HRV) of mothers and fetuses during a three-point OGTT using fetal magnetocardiography (fMCG). Measurements were performed in the fMEG Centre in Tübingen. After exclusion of 23 participants, 13 pregnant women with GDM and 36 pregnant women with normal glucose tolerance were examined. All women underwent the same examination setting with OGTT during which fMCG was recorded three times. Parameters of heart rate variability were measured. Compared with mothers with normal glucose regulation, mothers with GDM showed increased heart rate but no significant differences of maternal HRV. In contrast, HRV in fetuses of mothers with GDM differed from those in the metabolically healthy group regarding standard deviation normal to normal beat (SDNN) (P = 0.012), low-frequency band (P = 0.008) and high-frequency band (P = 0.031). These HRV parameters exhibit a decrease only in GDM fetuses during the second hour of the OGTT. These results show an altered response of the fetal autonomic nervous system to metabolic stress in GDM-complicated pregnancies. Hence, disturbances in maternal glucose metabolism might not only impact on the central nervous system of the fetus but may also affect the fetal autonomic nervous system. Metabolic stress reveals a different response of fetal autonomic nervous system in GDM-complicated pregnancies.

Ethnic analogies and differences in fetal heart rate variability signal: A retrospective study.

We aimed to analyze computerized cardiotocographic (cCTG) parameters (including fetal heart rate baseline, short-term variability, Delta, long-term irregularity [LTI], interval index [II], low frequency [LF], movement frequency [MF], high frequency [HF], and approximate entropy [ApEn]) in physiological term pregnancies in order to correlate them with ethnic differences. The clinical meaning of numerical parameters may explain physiological or paraphysiological phenomena that occur in fetuses of different ethnic origins. A total of 696 pregnant women, including 384 from Europe, 246 from sub-Saharan Africa, 45 from South-East Asia, and 21 from South America, were monitored from the 37th to the 41st week of gestation. Statistical analysis was performed with the analysis of variance test, Pearson correlation test and receiver-operator curves (P<0.05). Our results showed statistically significant differences (P<0.05) between white and black women for Delta, LTI, LF, MF, HF, and ApEn; between white and Asian women for Delta, LTI, MF, and the LF/(HF + MF) ratio; and between white and Latina women for Delta, LTI, and ApEn. In particular, Delta and LTI performed better in the white group than in the black, Asian, and Latina groups. Instead, LF, MF, HF, and ApEn performed better in the black than in the white group. Our results confirmed the integrity and normal functionality of both central and autonomic nervous system components for all fetuses investigated. Therefore, CTG monitoring should include both linear and nonlinear components of fetal heart rate variability in order to avoid misinterpretations of the CTG trace among ethnic groups.

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.

Effect of maternal position on fetal behavioural state and heart rate variability in healthy late gestation pregnancy

Fetal behavioural state in healthy late gestation pregnancy is affected by maternal position. Fetal state 1F is more likely to occur in maternal supine or right lateral positions. Fetal state 4F is less likely to occur when the woman lies supine or semi-recumbent. Fetal state change is more likely when the woman is supine or semi-recumbent. Fetal heart rate variability is affected by maternal position with variability reduced in supine and semi-recumbent positions. Fetal behavioural states (FBS) are measures of fetal wellbeing. In acute hypoxaemia, the human fetus adapts to a lower oxygen consuming state with changes in the cardiotocograph and reduced fetal activity. Recent studies of late gestation stillbirth described the importance of sleep position in the risk of intrauterine death. We designed this study to assess the effects of different maternal positions on FBS in healthy late gestation pregnancies under controlled conditions. Twenty-nine healthy women had continuous fetal ECG recordings under standardized conditions in four randomly allocated positions, left lateral, right lateral, supine and semi-recumbent. Two blinded observers, assigned fetal states in 5min blocks. Measures of fetal heart rate variability were calculated from ECG beat to beat data. Compared to state 2F, state 4F was less likely to occur when women were semi-recumbent [odds ratio (OR)=0.11, 95% confidence interval (95% CI) 0.02, 0.55], and supine (OR=0.27, 95% CI 0.07, 1.10). State 1F was more likely on the right (OR=2.36, 95% CI 1.11, 5.04) or supine (OR=4.99, 95% CI 2.41, 10.43) compared to the left. State change was more likely when the mother was semi-recumbent (OR=2.17, 95% CI 1.19, 3.95) or supine (OR=2.67, 95% CI 1.46, 4.85). There was a significant association of maternal position to mean fetal heart rate. The measures of heart rate variability (SDNN and RMSSD) were reduced in both semi-recumbent and supine positions. In healthy late gestation pregnancy, maternal position affects FBS and heart rate variability. These effects are likely fetal adaptations to positions which may produce a mild hypoxic stress.

Impacts of maternal anxiety on non-stress test parameters

Objective: To determine the association between antenatal maternal anxiety with non-stress test (NST) parameters, which is an indicator test of fetal well-being in the third trimester. Materials and Methods: Between January and December of 2013, 212 pregnant women, with 36-41 weeks of gestation were assessed with measures of distress and anxiety with Beck Anxiety Inventory (BAI) and with NST. The new National Institute Child Health and Human Development (NICHD) 2008 guideline criteria were used for interpretation of NST. Anxiety scores were grouped as minimal, mild, moderate, and severe. The impact of anxiety on NST parameters were investigated. Result: Anxiety scores were inversely correlated with fetal heart rate (FHR) accelerations (r = -0.631, and r = -0.855), number of fetal movements (r = -0.633, r = -0.860), FHR variability scores (r = -0.650, r = -0.877). and NST scores (r = -0.505, r = 0.729), (for all p Conclusion: The study showed that severe form of anxiety significantly affects NST parameters in near-term pregnancies.

Parasympathetic tone variations according to umbilical cord pH at birth: a computerized fetal heart rate variability analysis.

Non-reassuring fetal heart rate tracings reflect an imbalance between the parasympathetic and sympathetic nervous systems. In this situation, fetal asphyxia can be suspected and may be confirmed by metabolic measurements at birth like low pH or high base deficit values. The objective of this study was to determine whether fetal asphyxia during labor is related to parasympathetic nervous system activity. This is a retrospective study of a database collected in 5 centers. Two hundred and ninety-nine fetal heart rate tracings collected during labor were analyzed. Autonomic nervous system, especially the parasympathetic nervous system, was analyzed using an original index: the FSI (Fetal Stress Index). The FSI is a parasympathetic activity evaluation based on fetal heart rate variability analysis. Infants were grouped based on normal or low pH value at birth. FSI was measured during the last 30min of labor before birth and compared between groups. The minimum value of the FSI during the last 30min before delivery was significantly lower in the group with the lower umbilical cord arterial pH value. In this pilot study during labor, FSI was lower in the group of infants with low arterial pH at birth.

Quality Predictors of Abdominal Fetal Electrocardiography Recording in Antenatal Ambulatory and Bedside Settings

Background: Fetal electrocardiography using an abdominal monitor (Monica AN24™) could increase the diagnostic use of fetal heart rate (fHR) variability measurements. However, signal quality may depend on factors such as maternal physical activity, posture, and bedside versus ambulatory setting. Methods: Sixty-three healthy women wore the monitor at home and 42 women during a hospital stay. All women underwent a posture experiment, and all home and 13 hospital participants wore the monitor during daytime and nighttime. The success rate (SR) of fHR detection was analyzed in relation to maternal physical activity, posture, daytime versus nighttime, and other maternal and fetal predictors. Results: Ambulatorily, the SR was 86.8% for nighttime and 40.2% for daytime. The low daytime SR was largely due to effects of maternal physical activity and posture. The in-hospital SR was lower during nighttime (71.1%) and similar during daytime (43.3%). SR was related to gestational age, but not affected by pre-pregnancy and current body mass index or fetal growth restriction. Conclusions: The success of beat-to-beat fHR detection strongly depends on the home/hospital setting and predictors such as time of recording, activity levels, and maternal posture. Its clinical utility may be limited in periods of unsupervised recording with physical activity or posture shifts.

Fetal heart rate variability mediates prenatal depression effects on neonatal neurobehavioral maturity

This study analyzed the mediating role of fetal heart rate variability (FHR) on prenatal depression and neonatal neurobehavioral maturity. A sample of 104 pregnant women was recruited and divided into two groups according to their Edinburgh Postnatal Depression Scale (EPDS) scores (depressed/non-depressed). FHR variability in response to speech stimuli was assessed at term (between 37 and 39 weeks gestation). The neonates were then assessed on the Neonatal Behavioral Assessment Scale (NBAS) during the first 5days after birth. The fetuses of non-depressed pregnant women showed higher HR variability than the fetuses of depressed pregnant women in response to speech stimuli, and later as neonates they performed more optimally on the NBAS (on autonomic stability and total scores). FHR variability mediated the relationship between the mother’s prenatal depression and the neonatés NBAS performance. Prenatal depression effects on neonatal behavior may be partially explained by its adverse effects on fetal neurobehavioral maturity.

The influence of physical activity during pregnancy on maternal, fetal or infant heart rate variability: a systematic review.

BackgroundPhysical activity (PA) during pregnancy has been shown to be associated with several positive effects for mother, fetus, and offspring. Heart rate variability (HRV) is a noninvasive and surrogate marker to determine fetal overall health and the development of fetal autonomic nervous system. In addition, it has been shown to be significantly influenced by maternal behavior. However, the influence of maternal PA on HRV has not yet been systematically reviewed. Therefore, the aim of this systematic review was to assess the influence of regular maternal PA on maternal, fetal or infant HRV.MethodsA systematic literature search following a priori formulated criteria of studies that examined the influence of regular maternal PA (assessed for a minimum period of 6 weeks) on maternal, fetal or infant HRV was performed in the databases Pubmed and SPORTDiscus. Quality of each study was assessed using the standardized Quality Assessment Tool for Quantitative Studies (QATQS).ResultsNine articles were included into the present systematic review: two intervention studies, one prospective longitudinal study, and six post-hoc analysis of subsets of the longitudinal study. Of these articles four referred to maternal HRV, five to fetal HRV, and one to infant HRV. The overall global rating for the standardized quality assessment of the articles was moderate to weak. The articles regarding the influence of maternal PA on maternal HRV indicated contrary results. Five of five articles regarding the influence of maternal PA on fetal HRV showed increases of fetal HRV on most parameters depending on maternal PA. The article referring to infant HRV (measured one month postnatal) showed an increased HRV.ConclusionsBased on the current evidence available, our overall conclusion is that the hypothesis that maternal PA influences maternal HRV cannot be supported, but there is a trend that maternal PA might increase fetal and infant HRV (clinical conclusion). Therefore, we recommend that further, high quality studies addressing the influence of maternal PA on HRV should be performed (methodological conclusion).

Fetal motion estimation from noninvasive cardiac signal recordings

Fetal motility is a widely accepted indicator of the well-being of a fetus. In previous research, it has be shown that fetal motion (FM) is coherent with fetal heart rate accelerations and an indicator for active/rest cycles of the fetus. The most common approach for FM and fetal heart rate (FHR) assessment is by Doppler ultrasound (DUS). While DUS is the most common approach for studying the mechanical activities of the heart, noninvasive fetal electrocardiogram (ECG) and magnetocardiogram (MCG) recording and processing techniques have been considered as a possible competitor (or complement) for the DUS.In this study, a fully automatic and robust framework is proposed for the extraction, ranking and alignment of fetal QRS-complexes from noninvasive fetal ECG/MCG. Using notions from subspace tracking, two measures, namely the actogram and rotatogram, are defined for fetal motion tracking. The method is applied to four fetal ECG/MCG databases, including twin MCG recordings. By defining a novel measure of causality, it is shown that there is significant coherency and causal relationship between the actogram/rotatogram and FHR accelerations/decelerations. Using this measure, it is shown that in many cases, the actogram and rotatogram precede the FHR variations, which supports the idea of motion-induced FHR accelerations/decelerations for these cases and raises attention for the non-motion-induced FHR variations, which can be associated to the fetal central nervous system developments. The results of this study can lead to novel perspectives of the fetal sympathetic and parasympathetic brain systems and future requirements of fetal cardiac monitoring.

Maternal abuse history and reduced fetal heart rate variability: Abuse-related sleep disturbance is a mediator.

The consequences of childhood maltreatment are profound and long lasting. Not only does the victim of abuse suffer as a child, but there is mounting evidence that a history of maltreatment places the next generation at risk for significant psychopathology. Research identifies postnatal factors as affecting this intergenerational transmission of trauma. However, emerging evidence suggests that part of this risk may be transmitted before birth, passed on via abuse-related alterations in the in utero environment that are as yet largely unidentified. To date, no study has directly assessed the influence of pregnant women's abuse history on fetal neurobehavioral development, nor considered trauma-associated poor sleep quality as a mediator reflecting established physiological dysregulation. Using data from 262 pregnant adolescents (ages 14-19), a population at elevated risk for childhood maltreatment, the current study examined maternal emotional abuse history and sleep quality in relation to third-trimester fetal resting heart rate variability, an index of parasympathetic nervous system functioning. The results indicate that maternal emotional abuse history is indirectly associated with lower fetal heart rate variability via abuse-related sleep disturbances. These data demonstrate an association between maternal abuse histories and fetal development, showing that at least part of the intergenerational transmission of risk occurs during pregnancy.

A review of the safety of clozapine during pregnancy and lactation.

Clozapine is an antipsychotic used in the management of treatment-resistant schizophrenia. However, little is known about clozapine use during pregnancy and lactation, or its impact on the mother, foetus, and infant. This review aims to summarize the available literature on the safety of clozapine use during the perinatal period. EMBASE, PsycINFO, and MEDLINE were searched from their inceptions through June 2016. The review encompasses 21 studies that have examined clozapine use during pregnancy and lactation. The limited available data do not support an increased risk of congenital malformations in foetuses exposed to clozapine during pregnancy, though rates of gestational diabetes are twice as high in pregnant women using clozapine. Clozapine accumulation in foetal serum possibly contributes to increased rates of floppy infant syndrome at delivery, decreased foetal heart rate variability, and seizures in infancy. Clozapine crosses the placenta and also accumulates in breast milk, which may increase the risk of agranulocytosis in infants and may necessitate infant testing. The majority of these data come from case reports and case series, making it unclear if the published risks associated with clozapine are due to mental illness, lifestyle factors, or co-treatment with other psychotropic medications. While the available literature on clozapine use during the perinatal period is very limited, the risks of clozapine use during pregnancy and the postpartum period should be discussed with women and weighed against those associated with other treatments and partially or untreated schizophrenia.

Case 2: Early-onset Liver Failure With Palpable Abdominal Mass in a Neonate

A male infant is delivered at a gestational age of 35 weeks by urgent cesarean section for decreased fetal movements lasting more than 24 hours and decreased fetal heart rate variability with major decelerations. The mother is a healthy 35-year-old white, gravida 2 para 0 woman with an uneventful pregnancy except for diet-controlled gestational diabetes mellitus. Thick meconium-stained liquor is noted at birth. The infant is born nonvigorous and undergoes intubation and suctioning below the cords. He develops weak spontaneous respiration and is given free-flow oxygen, but no additional respiratory support is required. Apgar scores are 1, 8, and 8 at 1, 5, and 10 minutes, respectively. Arterial cord gas measurements are as follows: pH 7.00, partial pressure of carbon dioxide 84 mm Hg (11.17 kPa), and base deficit 10 mEq/L. The infant’s weight is 3,485 g (>95th percentile), length is 52 cm, and head circumference is 35 cm (both >90th percentile for gestational age). Clinical examination after birth reveals a palpable left hypochondrial mass and hepatomegaly. Laboratory results of note on day 1 are as follows: platelet count, 49 × 103/μL (49 × 109/L); alanine aminotransferase, 1,880 U/L (31.4 μkat/L); aspartate aminotransferase, 381 U/L (6.36 μkat/L); lactate dehydrogenase, >20,000 U/L (334 μkat/L); international normalized ratio (INR), 2.95; activated partial thromboplastin time, 35.9 seconds; fibrinogen, 84 mg/dL (2.5 μmol/L); D-dimer, greater than 3.5 μ/dL; serum albumin, 1.8 g/dL (18 g/L); serum ferritin, 844 ng/dL serum ammonia, 76.6 μ/dL. Blood and cerebrospinal fluid microbiological cultures and herpes virus polymerase chain reaction are reported negative. Among significant radiologic findings, abdominal ultrasonography on the first day after birth reveals a …

External Cephalic Version: Some Tricks of the Trade.

External Cephalic Version: Some Tricks of the Trade.

Acute fetal heart rate tracing changes secondary to cigarette smoking in third trimester pregnancies

Objective: In this study, we aimed to assess the acute alterations on some features of fetal heart rate (FHR) tracings in third trimester pregnancies.Methods: Data of FHR tracing records were obtained from 79 otherwise healthy pregnant women aged between 18 and 41. Among 79 women, 39 were nonsmokers while the remaining were chronic smokers (six or more cigarettes per day, with an average of 10 cigarettes per day). The baseline of tracings, the number of accelerations and decelerations of FHR, as well as the FHR mean, standard deviation, short-term variability of FHR were all calculated for each participant. The results of smokers and nonsmokers, then the results of smokers before and after smoking were compared.Results: Comparison of some demographic and FHR tracing characteristics between smoker and nonsmoker groups indicated significantly decreased variability in smoker group. All FHR tracing characteristics were compared before and, immediately after cigarette smoking and revealed significantly higher mean baseline, lower variability and acceleration after smoking a cigarette.Conclusion: Even in a short time period, smoking is associated with some changes in FHR monitorization characteristics, detailed analyses of these changes may clarify the pathophysiology of smoking associated perinatal outcome.