Lennart Nordström

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.

Routine oxytocin in the third stage of labour: a placebo controlled randomised trial

Objective To compare intravenous oxytocin administration (Partocon® 10 IU) with saline solution in the management of postpartum haemorrhage in the third stage of labour.

Determination of pH or lactate in fetal scalp blood in management of intrapartum fetal distress: randomised controlled multicentre trial

Objective To examine the effectiveness of pH analysis of fetal scalp blood compared with lactate analysis in identifying hypoxia in labour to prevent acidaemia at birth. Design Randomised controlled multicentre trial. Setting Labour wards. Participants Women with a singleton pregnancy, cephalic presentation, gestational age ≥34 weeks, and clinical indication for fetal scalp blood sampling. Interventions Standard pH analysis (n=1496) or lactate analysis (n=1496) with an electrochemical microvolume (5 μl) test strip device. The cut-off levels for intervention were pH <7.21 and lactate >4.8 mmol/l, respectively. Main outcome measure Metabolic acidaemia (pH <7.05 and base deficit >12 mmol/l) or pH <7.00 in cord artery blood. Results Metabolic acidaemia occurred in 3.2% in the lactate group and in 3.6% in the pH group (relative risk 0.91, 95% confidence interval 0.61 to 1.36). pH <7.00 occurred in 1.5% in the lactate group and in 1.8% in the pH group (0.84, 0.47 to 1.50). There was no significant difference in Apgar scores <7 at 5 minutes (1.15, 0.76 to 1.75) or operative deliveries for fetal distress (1.02, 0.93 to 1.11). Conclusion There were no significant differences in rate of acidaemia at birth after use of lactate analysis or pH analysis of fetal scalp blood samples to determine hypoxia during labour. Trial registration ISRCT No 1606064.

Routine measurements of umbilical artery lactate levels the prediction of perinatal outcome

OBJECTIVE Our purpose was to compare lactate levels with acid-base balance in the umbilical artery with respect to the prediction of pregnancy outcome. STUDY DESIGN A prospective study of 4045 cord samples was performed. Lactate was measured with a new method that requires 5 microliters of blood and provides the result within 1 minute. RESULTS The umbilical artery lactate concentrations were significantly elevated in instrumental deliveries (2.65 +/- 1.2 mmol/L) and in emergency cesarean sections (2.44 +/- 1.7 mmol/L) compared with spontaneous vaginal delivery (1.87 +/- 0.94 mmol/L) (p < 0.001, p < 0.001). Lactate correlated significantly to fetal pH, hemoglobin, base deficit, PCO2, and HCO3-. Lactate was comparable to pH and base deficit in sensitivity, specificity, and positive and negative predictive values in relation to morbidity and mortality. CONCLUSION Umbilical artery lactate concentration and acid-base balance predicted perinatal outcomes with similar efficacies; however, its simplicity makes lactate analysis an interesting alternative in obstetric care.

Scalp blood lactate: a new test strip method for monitoring fetal wellbeing in labour

Objective To determine fetal scalp blood lactate with a new test strip method in parturients with normal and abnormal cardiotocograms during labour and to describe the relation to maternal lactate, fetal scalp blood pH, cord artery lactate and acid‐base balance.

Quality assessment of two lactate test strip methods suitable for obstetric use.

Accuracy of lactate determinations in cord blood was tested for one reflectometric (Accusport) and one amperometric (Lactate Pro) microvolume test strip lactate meter. Both meters, using a whole blood sample, measure lower levels of lactate than a reflectometric device considered as a reference method, which analyses lactate in plasma. Readings were unaffected irrespective of lactate concentrations for the Lactate Pro, whilst the Accusport overestimated low lactate concentrations and underestimated high values. Both lactate meters underestimated lactate concentrations at high hematocrits, as compared with the reference method. The Lactate Pro has a fixed sample volume of 5 microliters while the Accusport uses random blood drop as sample volume. However, in analyses with less than 20 microliters sample volume considerable underestimation was found with the Accusport. Coefficient of variation was 3.8-8.9% for the Accusport and 3.1-4.0% for the Lactate Pro within lactate concentrations between 2.1 and 5.3 mmol/l. The amperometric device, the Lactate Pro, performed best in these tests dealing with fetal blood lactate concentrations. The new technique can be a useful tool in perinatal research as well as in obstetric practice.

Warm tub bathing during labor: maternal and neonatal effects

Aim. To study possible detrimental maternal and neonatal effects of immersion in warm water during labor.

Lactate in fetal scalp blood and umbilical artery blood measured during normal labor with a test strip method

A new test strip method was used to determine the lactate concentration in fetal scalp blood during normal labor. Sixty‐six fetal scalp blood samples were collected at cervical dilatations between 4 cm and 10 cm. The mean lactate value was 1.7 + 0.8 mmol/1 simultaneously (1S.D.) and the mean pH sampled simultaneously was 7.36 ±0.04 (1S.D.). The corresponding values for base deficit was 2.1 (±1.9) and for pC02 5.8 (±0.8). No difference was seen in lactate concentrations or pH values in early compared to late first stage of labor. The mean lactate concentration in the umbilical artery immediately after delivery was 3.7 mmol/l±1.2(lS.D.). The method was easy to handle and gave the result within 60 seconds.

Lactate determination in vaginal fluids: a new method in the diagnosis of prelabour rupture of membranes

Objectives  To assess whether lactate determination in vaginal fluids, ‘Lac test’, can be used as a diagnostic test for prelabour rupture of membranes (PROM) and to derive the best cutoff value for a positive test.

Association between lactate concentration in amniotic fluid and dysfunctional labor

Objectives. To assess whether there is an association between high lactate concentration in amniotic fluid (AF) and labor dystocia. Design. Prospective observational study. Setting. Labor ward at General South Hospital, Stockholm, Sweden. Population and methods. Women in active labor attending labor ward, having at least two consecutive measurements of lactate concentration in AF, measured 60 minutes apart. Main outcome measure. Dysfunctional labor, defined as instrumental or operative delivery due to dystocia. Results. Among women with spontaneous vaginal deliveries (n =23) the mean lactate concentration in AF during labor was 8.9 mmol/l (range 6.6–10.8), and among women with operative delivery due to labor dystocia (n =31) the corresponding value was 10.9 mmol/l (range 8.0–16.1) (p<0.001). Of 29 women with a high lactate concentration (≥10.1 mmol/l) in at least two consecutive measures collected at least 60 minutes apart, 25 (86%) were delivered instrumentally/operatively due to dystocia. Using this definition of a positive test, the diagnostic accuracy to predict operative delivery due to dystocia was: sensitivity 81% (25/31), specificity 83% (19/23), positive predictive value 86% (25/29), and negative predictive value 76% (19/25). The likelihood ratio was 5.0 for a positive test and 0.2 for a negative test. Conclusions. High lactate concentration (≥10.1mmol/l) in at least two consecutive samples of AF collected during labor 60 minutes apart is strongly associated with dystocia. This method might be useful in clinical management to identify labor dystocia at an early stage of labor.