Clinical situation
A skilled obstetrician is often faced with a situation where the progress of labour has been arrested and the Action Line in the partogram has been passed. A lot of these deliveries will result in normal vaginal deliveries. There is, however, a significant number of these women who will go through a long, painful, parturition that will ultimately end in a caesarean, ventouse or forceps delivery.
In this situation, the appropriate action is often decided under the pressure of time. A normal vaginal delivery is the preferred option, while a long outdrawn labour, will put heavy strain on both the fetus and the mother. This can lead to complications such as fetal asphyxia or future pelvic floor dysfunction.
If the membranes are already ruptured, the current standard management for dysfunctional labour is oxytocin infusion. It is, however, well-known that oxytocin might be ineffective in many situations, and does not significantly reduce the caesarean rate (see references). |
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Scientific background
It has earlier been shown in several experimental studies (see references) that the uterus, like other muscles, is a lactate producer. There is substantial evidence that a raised lactate level in the uterine muscle leads to inhibition of muscle contractions, what is described as “dysfunctional labour” or “labour dystocia”.
A recent study shows that it is possible to monitor the state of the uterus by measuring lactic acid in amniotic fluid. The study also shows that it is possible to predict the mode of delivery very early in the delivery process, by measuring lactic acid in amniotic fluid (see references).
Uterus monitoring in practice
For the first time we have a tool, to support a correct clinical decision, in the above-described clinical situation. A high level of lactic acid in amniotic fluid indicates that the uterus is exhausted. To stimulate this kind of labour with a oxytocin infusion would be like asking a marathon runner to run an extra 10,000 meters after she or he has passed the finish line.
By measuring AFL, Amniotic Fluid Lactate level (AFL test) in a slow progressing labour, a decision can be taken on the correct clinical way to proceed.
A recent study shows that when high levels of lactic acid has been measured in amniotic fluid, the probability is very high that the delivery will end with caesarean, ventouse or forceps. In consultation with the mother, consideration should be given to whether the delivery should be ended, to avoid the risk of complications from a long birth and limit unnecessary suffering.
If the measured level of lactate in amniotic fluid is low in combination with slow progress of labour, a limited infusion of oxytocin, in accordance with clinical practice, should be considered.
