When the fetal heart rate pattern seen on CTG monitoring during labour is considered abnormal, clinicians typically use measures that aim at restoring the pattern to normal. This is often called intrauterine resuscitation. Some of the commonly used approaches are to change the birthing woman’s position, give intravenous fluids, or to administer oxygen. This post is part one of a five-part series looking at the evidence for intrauterine resuscitation.
This series was prompted by a new piece of research about whether intrauterine resuscitation is used as much as it should be. In this first post, I’ll summarise the key findings from the paper. The next four posts will explore what we know from research about the use of oxygen therapy, intravenous fluids, maternal position changes, and the cessation of oxytocin as forms of intrauterine resuscitation. (I’m not going to cover fetal stimulation but have written about this recently. You can read that post here.)
Amadori and colleagues from two Italian hospitals set out to document how often intrauterine resuscitation maneuvers were used and what maneuvers a panel of expert clinicians stated they would have used on reviewing the CTG. The maneuvers the researchers looked for were suspension of oxytocin, tocolysis (using drugs to slow down contractions), amnioinfusion (putting extra fluid into the amniotic space), oxygen therapy, intravenous fluids, digital scalp stimulation (called “Clark’s test” in the paper), and maternal repositioning.
Retrospective data were collected from women whose births were complicated by neonatal asphyxia. Asphyxia was defined as a cord pH of seven or less, a base excess of 12 mMol/L or less, a ten-minute Apgar of 5 or less, or the need for resuscitation longer than 10 minutes. From the total population of women with this complication who gave birth between December 2020 and February 2021, 26 women were selected at random to represent cases. For each case, four controls were selected from women who gave birth on the same day as the case but when asphyxia did not occur. Women with multiple pregnancies, preterm birth, pre-labour CTG abnormalities, or who were monitored by intermittent auscultation were excluded. The CTG trace, clinical data about the woman, mode of birth, and neonatal outcome data were collected for all cases and controls. The use of intrauterine resuscitation as recorded in the health records was noted. A panel of two obstetricians and two midwives with at least five years of experience in intrapartum care were asked to review each CTG, classify it using the FIGO guideline, and record what action they would have taken in response to the CTG. The panel were blinded to the neonatal outcome but were given data about what intrauterine resuscitation had been used.
Data from 80 women were assessed, 40 from each hospital. (It isn’t clear how the authors went from 26 women + 104 matched controls to 80 women, and what proportion of women whose baby had asphyxia were included in the final 80.) The caesarean section rate was 24% and the instrumental birth rate (all by vacuum extraction) was 36%. Maternal repositioning was the most common approach used (73%), followed by intravenous fluid administration (44%). There was a notable difference between the two hospitals in how often intravenous fluid administration was used (23 % vs 77%). Tocolysis, amnioinfusion, and oxygen administration were never used. Fetal scalp stimulation was used infrequently (3%), as was the suspension of oxytocin (9%). (What proportion of women were being given intravenous oxytocin was not described.) Use of more than one maneuver was typical. For instance, of the women who were repositioned, 53% also had intravenous fluids and 9% had oxytocin suspended.
The degree of agreement on the classification of the CTG was only fair with a kappa of 0.406 (this has been shown repeatedly in research). There was better (but still far from universal) agreement regarding when to use caesarean section (k 0.518) or to suspend the use of oxytocin (k 0.541). The rate of agreement on when to use oxygen (k -0.003), intravenous fluids (k 0.066), fetal stimulation (k 0.044), maternal repositioning (k 0.059), or vacuum extraction (k 0.353) was poor.
The authors concluded that intrauterine resuscitation maneuvers were underused in practice. Their use of retrospective records to identify the use of resuscitation measures is likely to result in under-representation of what actually happened (this was acknowledged by the authors). When there is a significant CTG abnormality, a lot of things happen at once and typically more than one clinician is involved in providing care. Doing the things is prioritised over documentation, so it is understandable that not all interventions might be recorded. Ethnographic observations of clinical practice would give a more reliable indicator.
The authors concluded with recommendations to audit the use of resuscitative measures and to standardise care. I would argue that the apparent low rate of use and the lack of agreement among clinicians accurately reflects the absence of a strong evidence base to inform practice. Caution needs to be applied before attempting to standardise the management of women with an abnormal intrapartum fetal heart rate pattern. In an ideal world, we would only use approaches that have been shown to be effective and to have low levels of harm. As I plan to explore over the coming weeks, we are not there yet.
Amadori, R., Aquino, C. I., Osella, E., Tosi, M., Vaianella, E., Galli, L., Surico, D., & Remorgida, V. (2022, Feb 8). The application of intrauterine resuscitation maneuvers in delivery room: actual and expected use. Midwifery, 107, 103279. https://doi.org/10.1016/j.midw.2022.103279