Fetal scalp blood sampling: Do pH and lactates provide the same information?

OBJECTIVE: Assess the discordance between scalp pH and lactates performed from the same sample during labor. METHOD: This single-center retrospective study included all women with a singleton fetus who had at least one fetal blood sample taken during labor. Some of them had up to seven samples. Scalp pH was the reference parameter for obstetric decision-making. The correlation between the pH and lactates was studied using Pearson coefficient. By categorizing the values as normal, pre-acidosis and acidosis, we were able to estimate agreement with Cohen's kappa coefficient. The frequency of discordance in the categorization and the factors related to it were studied with univariate and multivariable analyses. Cases of severe acidosis at birth (cord pH < 7.00) and cases with acidosis scalp lactates but normal scalp pH were analyzed. RESULTS: We analyzed 480 samples from 268 fetuses among the 2644 deliveries during the study periode. Fetal blood sampling represented 10 % of deliveries. The scalp pH and lactates results were strongly correlated (r=-0.83), but their agreement was only fair (K = 0.36). In 29.4 % of cases, pH and lactates were discordant. Factors related to discordance were meconium-stained fluid, sampling at full dilation and multiple sampling. Six infants (2.2 %) had severe acidosis at birth. Cases' analyses did not allow to conclude severe acidosis could have been avoided using scalp lactates for obstetric decision-making. CONCLUSION: For more than a quarter of the samples, results were discordant between scalp pH and lactates, especially when cervix was full dilated and when the amniotic fluid was meconium-stained. A randomized controlled trial comparing the relevance of each parameter according to the obstetrical situation would be necessary.

Changes in intrapartum maternal placental growth factor levels in pregnancies complicated by fetal compromise at term.

BACKGROUND: Intrapartum fetal compromise (IFC) may result from the gradual decline in placental function during labour and can precipitate adverse neonatal outcomes. Placental growth factor (PlGF) is a biomarker of placental function. This study aims to investigate maternal PlGF levels and adverse perinatal outcomes in term labour. METHODS: Prospective observational study (Mater Mothers' Hospital, Brisbane). Eligibility: 37+0- 42+0 weeks gestation, singleton, cephalic, non-anomalous pregnancies. Cases of pre-eclampsia and fetal growth restriction were excluded. Maternal PlGF was sampled at the onset of the first stage of labour (1st PlGF) and again at the second stage (2nd PlGF). RESULTS: Sixty-three participants met inclusion criteria. Women requiring operative delivery (n = 11) for IFC had lower 1st PlGF (90.8 vs. 111.8 pg/ml) and 2nd PlGF (65.8 vs. 83.7 pg/ml) compared to the no-IFC cohort (n = 52). PlGF levels decreased significantly during labour in both the IFC (90.8 vs. 65.8 pg/ml, p = 0.021) and no-IFC (111.8 v 83.7, p < 0.001) cohorts, although the decline in PlGF levels was greater in the IFC cohort (-41.8% vs. -23.4%, p = 0.385). Maternal PlGF levels were significantly lower in those with an abnormal fetal heart rate pattern, cord arterial pH < 7.2, nursery admission and composite adverse neonatal outcome (CANO). PlGF decline was not correlated to duration of labour but was influenced by nulliparity and induced labour. CONCLUSIONS: Maternal PlGF levels are lower in pregnancies complicated by IFC and CANO, and declines more sharply during labour compared to the no-IFC cohort. The utility of PlGF as a predictor of IFC should be further investigated with clinical trials.

Examiner's finger-mounted fetal tissue oximetry: a preliminary report on 30 cases.

OBJECTIVE: To describe preliminary experience with a finger-mounted fetal tissue oximetry probe during the 2nd stage of labor. MATERIALS AND METHODS: A total of 30 term pregnant women without pregnancy complications were recruited. We measured fetal tissue oxygen saturation (FtO2) by using a finger-mounted fetal tissue oximetry during cervical examinations in the 2nd stage of labor. The data capturing rate of FtO2 and the interclass correlation coefficient were also examined. The mean FtO2 was compared to the neonatal condition assessed by the levels of umbilical cord blood. RESULTS: FtO2 was obtained in all cases, regardless of wetness, hair color, the part of the fetal head that was exposed, rotation of the fetus, color of amniotic fluid, and caput succedaneum. The mean FtO2 was 65.5%±8.58% in normal neonates [Apgar score >7 (1 min), n=25]. The mean FtO2 was significantly correlated with umbilical cord arterial pH (r=0.52, P=0.0030, n=30), but not with umbilical cord arterial partial pressure of oxygen. The interclass correlation coefficient was 0.94. CONCLUSIONS: Tissue oxygen saturation of the fetal head was obtained easily by the examiner's finger-mounted fetal tissue oximetry.

Blood gas analysis of bovine fetal capillary blood during stage II labor.

The aim of this study was to determine whether blood gas variables in fetal capillary blood during the last 30 min of stage II labor can be used to diagnose fetal asphyxia. Twenty-five newborn calves were used to investigate the correlation between capillary blood gas values obtained from the dorsolateral aspect of the distal pastern and those in arterial and venous blood. The pH, partial pressure of oxygen, partial pressure of carbon dioxide, concentration of bicarbonate, base excess and oxygen saturation were determined. The bicarbonate concentration (arterial, r=0.759; venous, r=0.766; both P<0.0001) and base excess (arterial, r=0.730; venous, r=0.807; both P<0.0001) had the highest correlations. Fetal capillary blood was collected during the last 30 min of stage II labor and the results of blood gas analysis were compared with those of arterial and venous blood collected immediately after birth in 38 calves. The pH (arterial, r=0.806; venous, r=0.885; both P<0.0001) and base excess (arterial, r=0.822; venous, r=0.871; both P<0.0001) had the highest correlations. The pH and base excess were significantly lower after birth than during the last 30 min of stage II labor. The severity of fetal acidosis during stage II labor can be easily and reliably determined using the pH or base excess of fetal capillary blood.

Follistatin serum concentrations during full-term labour in women--significant differences between spontaneous and induced labour.

Follistatin has been isolated from human placenta and has been identified in human foetal membranes and fluids. Serum follistatin levels in women rise during pregnancy particularly near term. In this study, we examined the effect of induction and stage of labour on maternal plasma concentrations of follistatin. Women who gave birth after a normal pregnancy were retrospectively divided into three groups: those who went in labour spontaneously (n = 33), needed induction by amniotomy and IV oxytocin (n = 18) or underwent planned caesarean section (n = 10). Serum was collected at 38-40 weeks of gestation, periodically through labour with a vaginal examination and once within 36 h postpartum and assayed for oestradiol, progesterone, prolactin and C-reactive protein. Follistatin was measured using a rabbit antiserum (#204) raised against purified 35 kDa bovine follistatin. Human recombinant follistatin was used as both standard and tracer. Concentrations of follistatin at 38-40 weeks of gestation were significantly different between groups. Those who had a spontaneous labour had concentrations higher than those who were induced. Similarly, those who were induced had concentrations higher than those who underwent a caesarean. In the spontaneous group, follistatin rose during labour, peaking at 57.9 +/- 5.48 ng/ml at > 3 cm of cervical dilation, and after delivery follistatin decreased to 26.16 +/- 3.4 ng/ml at 24 h post-delivery. In induced patients follistatin continued increasing to peak following delivery at 26.9 +/- 3.0 ng/ml and decreased at > 3 h post-delivery. Follistatin concentrations in caesarean section patients at 24 h post-surgery (18.53 +/- 3.74 ng/ml) were not different from that before the surgery and were comparable with the other two groups. Follistatin is clearly implicated in the onset of labour; however, further studies with a larger cohort of women are necessary to determine the nature of its role.

Fear, pain and stress hormones during childbirth.

AIMS: To investigate the course of fear, pain and stress hormones during labor, and the associations between fear, pain, stress hormones and duration of labor in nulliparous women with and without epidural analgesia (EDA). METHOD: One day during gestation weeks 37-39, urinary and salivary samples were collected to measure catecholamines and cortisol. Hourly during labor, the participants answered the Delivery Fear Scale and a pain intensity scale, and urinary and salivary samples were collected to measure stress hormones. RESULTS: The course of fear, pain and stress hormones differed throughout labor in women with and without EDA. Pain and cortisol increased throughout labor in women without EDA. Women who received EDA had more fear, but not more pain, before the administration of the EDA than women who did not receive EDA. Pain, fear and catecholamines decreased when women received EDA, but fear and pain increased again later in labor. Fear and pain correlated, as well as levels of fear in the different phases of labor. During phase one of labor epinephrine and duration of the phase were negatively correlated. CONCLUSION: The course of fear, pain and concentrations of stress hormones differed, highly influenced by the administration of EDA. Fear and pain correlated more pronounced than stress hormones and fear, pain and duration of labor.

Are alterations in plasma protease concentrations during labor associated with poor obstetric outcomes?

OBJECTIVE: The purpose of this study was to assess the association between abnormal connective tissue remodeling during labor as reflected by plasma concentrations of extracellular matrix remodeling proteolytic enzymes and adverse obstetric outcomes. STUDY DESIGN: A prospective observational study of 176 nulliparous women who attended the antenatal clinics at the Mercy Hospital for Women (Melbourne, Australia) from 1999 to 2000. RESULTS: Patients with a prolonged second stage (>120 minutes) had a significantly increased plasma concentration of matrix metalloproteinase 9 after delivery compared with control subjects (P<.001); patients in labor who underwent an emergency caesarean delivery had a significantly lower concentration (P<.001). Patients with a prolonged duration of labor (>11 hours) had a significantly lower urokinase plasminogen activator plasma concentration compared with control subjects (P<.01). CONCLUSION: Altered plasma concentrations of extracellular matrix remodeling proteolytic enzymes, matrix metalloproteinase 9, and urokinase plasminogen activator were found to be associated with abnormal labor and delivery outcomes. This finding may provide a useful predictor of abnormal obstetric outcomes.

[Reference values range of the fetal oxygen saturation and its dispersal during labor without cardiotocographic evidence for fetal distress].

UNLABELLED: The objective of this study is to establish the reference values range of the fetal oxygen saturation during the first and the second period of labor and their dispersal according to the extent of cervical dillatation in cases with normal FHR--absence of fetal hypoxia and asphyxia of the newborn. MATERIAL AND METHODS: This is a prospective study which involves 94 women with normal FHR. All of the newborns are with umbilical artery pH values greater than 7.15 and 5 min Apgar score greater than 7; there was no necessity for any reanimation procedures, assisted ventilation or intensive care treatment. The fetal oxygen saturation (SpO2) is monitored by fetal pulseoxymeter Nellcor N 400, fetal sensors FS - 14. Cardiotocographic monitoring is carried out simultaneously. Blood is obtained from the fetal scalp during labor for blood gas and pH analysis, and umbilical artery pH as well as the Apgar score of the newborn are determined. RESULTS: The average monitoring time during the first period of labor is 107.19+/-29.49 min. with reliability of the recordings 86.54+/-6.10%. The average monitoring time for the second period of labor is 36.72+/-8.31 min. with reliability of the recordings 75.42 +/-9.61%. The mean SpO2 values are 48.71+/-5.52% during the first period and 47.30+/-4.62% during the second period of labor. The reference SpO2 values ranging between the 25-th and 75-th percentile in fetuses with normal FHR are 46-52 % for the first and 44-50 % for the second period. The results for fetal SpO2 during the different stages of cervical dillatation are as follows: for 4-5 cm - 49.49+/-5.12%, for 6-7 cm - 48.76+/-5.42%, for 8-9 cm - 48.39+/-5.49%. CONCLUSIONS: The fetal SpO2 dispersal during cervical dillatation of 4-5, 6-7 and 8-9cm accordingly demonstrates a nonsignificant decrease of SpO2 for the different groups (p>0.05). The fetal SpO2 dispersal between the first and the second period of labor also demonstrates decrease of SpO2 values and shows a minor statistically significant difference (p < 0.05 - Repeated measures ANOVA), which is considered to be within the normal range and does not reflect on the newborn's well-being.

Deterioration in cord blood gas status during the second stage of labour is more rapid in the second twin than in the first twin.

OBJECTIVE: To compare in twin pregnancy the rate of deterioration in umbilical blood gas status during the second stage of labour, and to investigate whether the duration of the first twin's delivery has any effect on the blood gas status of the second twin. DESIGN: A retrospective study. SETTING: Department of Obstetrics and Gynaecology in a university teaching hospital. POPULATION: Twin pregnancies with both of the twins delivered by normal cephalic vaginal mode, at or beyond 34 weeks of gestation, over a period of seven years. Twins with any maternal or fetal complications including discordant growth, intrauterine growth restriction, intrauterine death, fetal malformations, fetal distress, pre-eclampsia and diabetes were excluded. METHODS: The first twins' second stage was defined as from the start of maternal pushing to his/her delivery, while the second twins' second stage started after the delivery of the first twin and ended by his/her delivery. The total duration of the second stage was the sum of the above two intervals. The correlations between the first twins' umbilical cord blood gas parameters and the duration of their own second stage, the second twins' umbilical cord blood gas parameters and the duration of their own second stage, as well as that of the total second stage, were studied. MAIN OUTCOME MEASURES: The changes of umbilical arterial pH of each twin with the duration of the corresponding second stage of labour, and the difference among them. RESULTS: A total of 51 cases were reviewed. The median gestation at delivery was 37 weeks. The median duration of first twins' second stage was 10 minutes (range 1-75) while that of the second twins' was 10 minutes (range 3-26). The first twins' second stage was inversely correlated with their arterial pH, venous pH and base excess [BE] (P < 0.01). Both the second twins' second stage and the total second stage were inversely correlated with both of their arterial and venous pH and BE (P < 0.01). However, further multiple regression analysis suggested that the correlation of the total second stage with the second twins' cord blood parameters could be solely explained by their own second stage. The rate of reduction in the second twins' arterial pH was 4.95 x 10(-3) per minute, and was significantly faster than that of the first twins', which was 1.55 x 10(-3) per minute (P < 0.05). CONCLUSIONS: During normal vaginal delivery, the umbilical cord blood gas status of both the first and the second twins deteriorated with the duration of their corresponding second stages, but the effects are greater in the latter. Furthermore, the duration of the first twins' second stage does not affect the blood gas status of the second twins'. These observations support the postulation of a diminished uteroplacental exchange function after the delivery of the first twin. Close monitoring and expeditious delivery of the second twins are important.

Changes in platelet function, volume and count during labor and 24 hours postpartum.

Increased platelet activation has been reported during labor. We evaluated changes in platelet count, volume and function during labor and 24 hours postpartum. Platelet function during labor was not previously evaluated. Twenty-five healthy women in labor, subsequently having singleton spontaneous vaginal delivery following uncomplicated pregnancy at term were recruited for this prospective study. Blood was withdrawn during latent phase, active phase, second stage of labor, and 24 hours postpartum. Platelet function was assessed by hemoSTATUS2 test (Hepcon, Medtronic, USA). Twenty-five healthy non-pregnant volunteers served as controls. Platelet count and volume did not change significantly throughout labor and 24 hours postpartum. Platelet function was 120.8 +/- 26.9 %, 106.8 +/- 24.6 % (p = 0.06), 105.2 +/- 30.9 % (p < 0.05), and 117.6 +/- 21.5 % during latent phase, active phase, second stage of labor, and 24 hours postpartum, respectively. Platelet function was altered during labor while platelet count and volume did not change significantly. Platelet function remained increased when compared to non-pregnant controls.

[Fetal arterial oxygen saturation (FSpO2) during the second stage of labor after training for childbirth]. / Wysycenie tlenem krwi plodowej (FSpO2) w drugim okresie porodu po przygotowaniu w Szkole Rodzenia.

OBJECTIVE AND DESIGN: The aim of the research was to determine the effects of participating in training program for childbirth in Maternity School in Lódz on the state of the fetus. In the above research, the authors presented the foetal oxygen saturation (FSpO2) during the second stage of labour among the women participating in Maternity School as well as a control group. Our study analysed the neonatal outcome too (umbilical arterial blood pH and 5 min. Apgar score). MATERIAL AND METHODS: The test group consisted of eighty seven (87) healthy primigravidas of whom forty two (42) participated in classes in the Maternity School and forty fifth (45) made up the control group. Validity of the correlation was assessed by means of t-Student's table of N--2 degree of freedom. RESULTS: The medium parameters of FSpO2 values and duration of the second stage of labor in both groups were shown. Statistically significant differences between the groups were found in duration the second stage of labour--in Maternity School group being shorter. Statistically significant differences in FSpO2 values between groups were not observed.

Fetal and maternal lactate increase during active second stage of labour.

OBJECTIVE: To determine longitudinally fetal and maternal blood lactate concentrations during the second stage of labour. DESIGN: Prospective, observational study of randomly selected labours. SETTING: Labour ward, Sultanah Aminah General Hospital, Johore Bahru, Malaysia. MAIN OUTCOME MEASURES: Fetal scalp and maternal venous blood lactate, umbilical arterial and vein lactate and acid-base balance at delivery. RESULTS: Sixty-nine women and their infants were monitored in the second stage of labour. Mean maternal venous lactate by the end of the first stage was 2.6 +/- 1.0 (+/- S.D.) mmol/L and increased to 3.6 +/- 1.4, 4.2 +/- 1.7. 4.8 +/- 1.6, 5.4 +/- 2.1 and 4.3 +/- 0.9 mmol/L, respectively, for every 15 minute of bearing down. Corresponding values for fetal scalp blood lactate were 2.4 +/- 1.1, 3.1 +/- 1.6, 3.2 +/- 1.8, 4.2 +/- 2.4, 4.9 +/- 2.8 and 5.8 +/- 1.9 mmol/L. The mean slope of maternal lactate increase was 0.070 mmol/L per minute (95% CI 0.050, 0.090) and for fetal lactate increase 0.032 mmol/L per minute (95% C.I.: 0.018, 0.045). The duration of active second stage was significantly associated with fetal lactate (P < 0.001) and maternal lactate (P = 0.03) at the time of crowning of the fetal head, and lactate in umbilical arterial and vein blood at delivery (P < 0.001). Expulsion time > or = 45 minutes, compared with shorter active second stage, and acidaemia at birth implied larger arterial-venous lactate differences (P < 0.001). Fetal lactate at crowning was also significantly associated with the umbilical arterial-veonus lactate difference (P = 0.03). CONCLUSIONS: Maternal and fetal lactate concentrations increase significantly with duration of the active second stage of labour, more rapidly in the mother. It is likely that fetal anaerobic metabolism is the main source for the fetal lactate increase.

Fetal oxygen saturation during maternal bearing down efforts in the second stage of labor.

Fetal oxygen saturation (FSpO2) was monitored with the Nellcor Puritan Bennett N400/FS14 system during 16 labors to establish whether FSpO2 was influenced by maternal bearing down efforts in the second stage of labor. Fetal SpO2 is reported for 16 fetuses where neonatal outcome was normal. One hour of continuous data was recorded: 30 min prior to the onset of maternal bearing down efforts and the first 30 min of pushing. The hour was divided into six epochs of 10-min duration. Differences between mean FSpO2 for the two 30 min of monitoring and for each epoch were sought using repeated measures analysis of variance (ANOVA). The mean FSpO2 for the total 30 min prior to the onset of pushing was 49% (95% confidence intervals 46.5-50.6%), compared to a mean of 46% (95% confidence intervals 43.6-48.7%) during the first 30 min of pushing [F (1, 2.25), p = 0.14]. There was no significant decline in mean FSpO2 for each epoch. Apgar scores at 5 min were all > 7 and umbilical arterial pH values were > or = 7.20 (n = 12). We concluded that mean FSpO2 recorded prior to the onset of maternal bearing down efforts was not significantly different to mean FSpO2 during pushing, with normal neonatal outcome.

The impact of antenatal and perinatal variables on cord blood haemopoietic stem/progenitor cell yield available for transplantation.

We investigated the impact of maternal and fetal variables on cord blood (CB) haemopoietic stem/progenitor cell content. These included maternal age, ethnic origin, parity, ABO and Rhesus D blood group, antenatal haemoglobin, alcohol and cigarette consumption at time of registration, mode of delivery, duration of the first and second stages of labour, gestational age, birth weight, cord pH and cord erythrocyte mean cell volume (MCV). Cord volumes and total nucleated cellularities (TNC) were recorded, the colony assay for granulocyte-macrophage colony-forming-cells (CFU-GM) was used to quantify the progenitor cells and the potential of CFU-GM to produce secondary colonies on replating was used as a measure of progenitor cell quality. We found: (1) significantly greater (P=0.04) volumes were collected from babies who weighed > or = 2.5kg versus babies with a birth weight <2.5kg; (2) significantly greater numbers of mononuclear cells (MNC) from mothers who drank 0-3 units versus those who drank > or = 4 units of alcohol weekly (P=0.03), and in babies with a cord pH < or = 7.1 v > 7.1 (P=0.02); (3) Significantly greater numbers of cord CFU-GM in mothers who drank 0-3 v > or = 4 units weekly (P=0.004) and smokers of > or = 10 v 0-9 cigarettes daily (P=0.02) and in spontaneous vaginal deliveries than assisted vaginal and caesarean deliveries (P=0.04), and (4) the potential of CFU-GM to produce secondary colonies was significantly greater in CB derived from Caucasians than from non-Caucasians ( P=0.02); in assisted vaginal delivery v spontaneous vaginal (P=0.02) and in deliveries with prolonged first stage of labour v short first stage of labour (P=0.04). We conclude that antenatal and perinatal variables may influence the CB stem/progenitor cell yield available for transplantation.

Fetal pulse oximetry and visual on-line signal identification in the second stage of labor.

OBJECTIVE: To determine the accuracy of reflection pulse oximetry and visual on-line signal identification during the second stage of labor. STUDY DESIGN: The reflection pulse oximetry system used allows visual on-line identification of valid signals by showing the original red and infrared signals. With this system oxygen saturation measurements are averaged over nine heartbeats only. An atraumatic suction probe was used. The measurements of the last 10 minutes before delivery were compared with umbilical venous cord blood samples taken soon after delivery. RESULTS: The correlation between reflection pulse oximetry readings during the last 10 minutes before delivery and umbilical vein oxygen saturation was significant (r = 0.45; p < 0.0005). Standard regression analysis showed R2 of 0.45. This did not change if weighted by the rate of valid signals (R2 = 0.42). If the predelivery loss of valid signals was less than 5 minutes, the correlation improved (r = 0.47, p < 0.001). Umbilical vein pH did not correlate with pulse oximetry readings. CONCLUSION: The reflection pulse oximetry system used allows visual on-line identification of even short periods of valid signals and reflects actual oxygen saturation in fetal arterial blood.

Plasma oxytocin during the first and second stages of spontaneous human labour.

A technique for complete oxytocinase inhibition has been combined with a rapid serial sampling strategy to determine plasma oxytocin concentrations in twelve women during the early and late first stage and in eight women throughout the second stage of labour. The progress of labour is not related to an increase in oxytocin concentration, uterine contractions are not associated with changes in plasma oxytocin concentration and hypocontractile labour does not appear to be the result of a deficit of oxytocin. The majority of patients do not demonstrate an increase in plasma oxytocin concentration during the second stage of labour; however, a minority produce a large surge immediately before delivery. The results do not support a role for oxytocin during spontaneous labour unless uterine activity is controlled by extremely low plasma hormone concentrations or the uterus becomes sensitive to a constant oxytocin concentration.

Complexoproductive and antiheparin properties of low density lipoproteins (LDL). II. Interaction of serum low density lipoproteins (LDL) with heparin of different molecular weight.

Quantity of unsoluble LDL complexes with heparin of different molecular weight in hypo-, normo-, and hyperlipemic blood serum in the presence of CaCl2 was estimated. At the same weight concentration the biggest quantity of LDL complexes are formed with heparin with heparin of the molecular weight 16000, the quantity is smaller with heparin of the molecular weight 5100, and it is the smallest with heparin of molecular weight 3700.