Ultrasound on a labouring woman’s perineum helps the attendant to know what’s going on.

This study was shared by one of our students, The efficacy of transperineal and transabdominal ultrasound findings in predicting spontaneous vaginal delivery during active labour, (Büyüknisan et al, 2025) that frankly made me nauseous and wanting to throw up.

From a Turkish hospital, 150 women in active labour were recruited and randomised to either hourly perineal and abdominal ultrasounds (along with vaginal exams) or just hourly vaginal exams from 6cms onwards.

A transperineal ultrasound takes the wand of an ultrasound, adds an appropriate amount of gel, and applies the wand to the perineum and vulva without penetrating her vagina.

The researchers wanted to know the clinical value of this intervention in relation to the mode of delivery, i.e., vaginal or caesarean surgery. In particular, they were measuring the angle of progression of the foetal head in relation to the symphysis pubis (AoP), the foetal head-to-perineum distance (HPD), and the midline angle (MA) of the foetal head.

Plenty of research has already been done on the value of perineal ultrasound vs digital (fingers) exam of the cervix and which one was better at estimating the centimetres of dilation. It seems to be a bit of a toss-up at to which one was more “accurate” since cervixes are notorious at being unpredictable (much like their owners). However, the ultrasound group tends to experience fewer infections since there’s fewer fingers going up their vaginas (Oberman et al., 2023).

The authors emphasised that ultrasound was an “objective” means of gathering information and predicting labour outcome. I think we could all agree that there’s little “objective” about having one’s genitals probed for information that then goes to a clinician to use for decision-making who has life experiences and biases just like the rest of us. Naturally, the star of the study was the ultrasound with no mention of the women’s experiences.

The outcome of the study was that “Serial intrapartum ultrasound measurements of AoP, (angle of progression), HPD (head-perineum distance), and MLA (midline angle) provide objective predictors of delivery mode during active labour. (…) Routine incorporation of these sonographic parameters may improve the quality of intrapartum clinical decisions and facilitate more efficient management of labour.” Which I suppose means playing the algorithmic odds and calling for a surgical delivery based on the numbers and lessening the opportunities for women to labour their babies out. It also means removing whatever humanity was left of the birth experience.

This reductionist approach to “management of labour” is why we’re seeing skyrocketing interventions without any evidence of benefit. Just who would benefit from these serial genital ultrasounds? Not the mother as every hour she is placed on her back, legs open, and probed. Not the baby who endures the bombardment of ultrasound waves. It simply elevates the hierarchy of technology in the sacred rite of passage of human birth. It contributes to the algorithm of birth that got it wrong in the first place.

While midwives have used vaginal examinations throughout history to gather information when a labour was presenting with difficulties, the routine use of vaginal exams to track progress became standard in the 1950’s thanks to the work of Emmanuel Friedman who explored the cervixes of 500 sedated first-time mothers and plotted his findings on a graph, which we call “Friedman’s Curve” (Friedman, 1955). He also gave us the words we use today, “first stage, latent, active, transition, second stage, and third stage”. According to our good friend Emmanuel, women’s cervixes dilate predictably and progressively, usually at a rate of 0.5 – 2 cm/ hour once in “active” labour. Sadly, he forgot to ask the women if they agreed with his conclusions, but of course 96% of them were sedated so they may not have had much input. As it turns out, we are more likely to ebb and flow, rise and fall, progress and plateau.

Once we had Friedman’s curve to mansplain labour for us, the partogram was introduced to track our progress to determine when we were “off the curve” and in need of an intervention to speed things up. The partogram requires routine cervical checks to plot our dilation and the descent of the baby on its graph.

Despite vaginal exams being considered the “gold standard” in academic literature in terms of labour management, there is actually no evidence to support its use (Downe et al., 2013). Further, its accuracy between practitioners is less than 50% (Buchmann & Libhaber, 2008) and it has no predictive value in determining when a baby will be born. In other words, a woman who is 2cm dilated may have the baby within an hour and a woman who is “fully dilated” at 10cm may still not have her baby for several hours.

However, our maternity culture is entirely fixated on that bit of tissue at the top of our vaginas, primarily because it can be reached by gloved fingers and provides a number, albeit often inaccurate, that can be plotted on a chart.

The recommendation that perineal ultrasound become the new “gold standard” (Pan et al., 2022) is still based on the premise that women’s bodies are some kind of (faulty) machine that benefits from careful monitoring and frequent interventions. Absent from this is the profound spiritual aspect of ushering in new life, the mother’s rite of passage, the baby’s initiation into our humanity, and the shaping of our future by how this is “managed”.

Since I don’t do vaginal exams to assess progress, I prefer to look at a woman’s face. It’s more interesting and offers more information. It also affords us the opportunity to connect woman-to-woman in this shared experience we call Life while removing the “objectification” that the medical industry seems to value.

While a vaginal exam might be helpful for gathering information to discuss next steps in a challenging labour, the current routine of poking, prodding, penetrating, or shooting ultrasound waves at a woman’s perineum in order to chart and “manage” her is an affront to the sacred act of bringing in life and to our collective humanity.