Intrapartum care

Advancement in science and technology provides the impetus for new applications and progress in the field of Perinatal Medicine. In this edition of the Journal of Perinatal Medicine, the characterization of new interventions to optimize fetal surveillance and intrapartum assessment are explored, as well as having an important look at the attitudes to decision-making for home delivery despite high risk contraindications. Research fosters knowledge and informs the decisions we make regarding interventions in pregnancy and it is exactly this purpose that the current articles in the journal strive to achieve.

Fetal ECG monitoring is regarded as a direct measure of fetal cardiac function and a recently available portable fetal ECG monitor was evaluated by Wacker-Gussmann and co-workers in Munich, Germany [1]. The analysis of the P wave, QRS-complex and T wave with the fetal cardiac time intervals (fCTIs) of 149 fetal ECGs in healthy pregnancies from 32 weeks gestation were prospectively characterized. The challenges and limitations of identifying the T wave for long QT syndrome and fetal arrhythmias are highlighted. These results set the stage for further research into the application of fetal ECG in fetal monitoring.

Short-term variation (STV) of the fetal heart rate (FHR) is a very important parameter in the monitoring and intervention of fetuses with intrauterine growth restriction (IUGR). Kouskouti and colleagues in Nürnberg, Germany evaluate a new algorithm for short-term variation of the fetal heart rate [2]. New technology allows the analysis of STV more precisely using STV240. For the correct interpretation and clinical application of this new algorithm, standardization of the parameters is required. This study provides recommendations for normal ranges through a prospective comparison of 228 cardiotocograms using the new and previously established algorithms in normal pregnancies between 24 and 34 weeks of gestation. This research now provides the background for further work and for setting the decision criteria in pregnancies with IUGR.

Hypercoiling of the umbilical cord has been identified as a potential marker for adverse perinatal outcomes. Ma’ayeh et al. in Pennsylvania, USA used prenatal ultrasound to examine the umbilical coiling index (UCI) in the second trimester and compare this with the postnatal measurement of umbilical cord coiling and the association with perinatal outcomes [3]. The study analyzed 72 uncomplicated pregnancies and showed no strong correlation between prenatal and postnatal umbilical cord coiling. The study explores the possible reasons for the low sensitivity of the UCI and questions the application of the measurement as a screening tool in the second trimester. The researchers rightly recommend larger studies to address the application of screening for hypercoiling of the umbilical cord.

Labor and delivery is a highly dynamic and complex process. Knowing when intervention is necessary to address prolonged labor is acutely dependent on the knowledge of the normal physiology and movement of the baby through the birth canal. Kimmich and coworkers in Zurich, Switzerland performed a retrospective cohort study looking at fetal descent rates in the active phase of labor, assessed clinically and calculated in centimeters per hour, for every fetal station level [4]. Their analysis of over 6000 deliveries identifies that the fetal descent accelerates in an exponential fashion during the active phase with increased acceleration noted in multiparous women. The study explores how this phenomenon is influenced by a number of intrapartum factors and suggest that it is not the duration of the second stage alone that distinguishes physiological from non-physiological labor but the rate of fetal descent.

Lactic acid dehydrogenase (LDH) is a recognized marker for newborn asphyxia and complements the measurements of lactate and arterial pH in the umbilical cord as hallmarks of fetal distress. LDH has a significant role in glycolytic metabolism and overcoming temporary oxygen debt. Wiberg-Itzel and colleagues in Stockholm, Sweden studied the relationship between three groups of pregnancy (healthy women, women with chronic health diseases and women with pregnancy-only related disease) and the umbilical artery LDH (aLDH) levels at birth [5]. The analysis of 1247 deliveries showed that despite higher median values of aLDH in babies of women with chronic diseases in pregnancy there was no significant increase in the incidence of high aLDH results compared to the other groups. The authors point to the greater role intrapartum fetal LDH may play in combination with fetal pH and lactate in identifying a fetus in distress.

Despite recent evidence that home births are associated with increased risk of neonatal morbidity and mortality, Zafman and coworkers in New York, USA show a worrying trend of an increase in the number of home births taking place across the USA where major contraindications to home delivery (vaginal birth after cesarean, breech and twins) were identified [6]. Their 25-year analysis of birth records at the National Center for Health Statistics explored characteristics and factors that may be contributing to this increase and they have identified a rising trend in the number of women with higher education and in those with the ability to individually finance the costs of the delivery care themselves. Whilst the American College of Obstetrics and Gynecology advocates a freedom of choice for planning the place of delivery, the study addresses identifying women where education and information on risks can help them make informed decisions.

The efforts and aspirations of these researchers and others to investigate and push the boundaries of our knowledge and to pursue the discovery of new applications and approaches which optimize the quality and safety of perinatal care will always be commended and act as an inspiration for further research in our multifaceted and interwoven profession of perinatal medicine.