Instrumental delivery and ultrasound : a multicentre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery

Abstract

Objective To determine whether the use of ultrasound can reduce the incidence of incorrect diagnosis of the fetal head position at instrumental delivery and subsequent morbidity. Design Two‐arm, parallel, randomised trial, conducted from June 2011 to December 2012. Setting Two maternity hospitals in the Republic of Ireland. Sample A cohort of 514 nulliparous women at term (≥37 weeks of gestation) with singleton cephalic pregnancies, aiming to deliver vaginally, were recruited prior to an induction of labour or in early labour. Methods If instrumental delivery was required, women who had provided written consent were randomised to receive clinical assessment (standard care) or ultrasound scan and clinical assessment (ultrasound). [Correction added on 17 April 2014, after first online publication: Sentence was amended.] Main outcome measure Incorrect diagnosis of the fetal head position. Results The incidence of incorrect diagnosis was significantly lower in the ultrasound group than the standard care group (4/257, 1.6%, versus 52/257, 20.2%; odds ratio 0.06; 95% confidence interval 0.02–0.19; P < 0.001). The decision to delivery interval was similar in both groups (ultrasound mean 13.8 minutes, SD 8.7 minutes, versus standard care mean 14.6 minutes, SD 10.1 minutes, P = 0.35). The incidence of maternal and neonatal complications, failed instrumental delivery, and caesarean section was not significantly different between the two groups. Conclusions An ultrasound assessment prior to instrumental delivery reduced the incidence of incorrect diagnosis of the fetal head position without delaying delivery, but did not prevent morbidity. A more integrated clinical skills‐based approach is likely to be required to prevent adverse outcomes at instrumental delivery.

Does ultrasound determination of fetal occiput position improve labour outcome?

“…1 We noted some flaws in the article. Firstly, among patient characteristics the fetal head station is not mentioned.…”

“…Their comments allow us to further clarify the methodology and results of our trial of the ultrasound assessment of fetal head position versus standard care at instrumental delivery. 1 We collected a large volume of data, not all of which was presented in the article. The randomisation process was successful for baseline variables, and this includes fetal station, as can be seen in Table 1 below.…”

Intrapartum Ultrasound to Differentiate Flexion and Deflexion in Occipitoposterior Rotation

“…In particular, several recent studies have addressed the most common malposition, the occipitoposterior (OP) presentation [1][2][3][4][5][6] . Allowing a precise prospective diagnosis, ultrasound has offered the opportunity to perform prospective studies with the aim to improve the management of these cases [3][4][5] . Like others, we have previously described the sonographic finding of the fetal Keywords Labor · Dystocia · Malpresentation · Malposition · Occiput posterior position · Brow presentation · Sinciput presentation · Ultrasound Abstract Objective: To evaluate the ability of intrapartum ultrasound to differentiate occipitoposterior (OP) rotation with normal flexion of the head from deflexion, to compare the accuracy of ultrasound with the digital examination, and to assess the outcome of labor according to the type of presentation.…”

“…In 3 of these cases, the orbits were at the same level of the pubis suggesting brow presentation. In the remaining 3 cases, the orbits oriented upward in a transverse view of the maternal abdomen as the hallmark of OP presentation [2,[4][5][6][7][8][9][10] , a variety of the vertex presentation that may obstruct labor but is compatible with spontaneous vaginal delivery in a substantial proportion of cases [11,12] . OP rotation may also occur with deflexed presentations, such as sinciput and brow, that are known to interfere to a greater extent with the descent of the fetal head [13][14][15] .…”

Knowledge, understanding and fetal occiput position

“…The complications associated with fetal occiput posterior position, such as neonatal encephalopathy and neonatal and maternal trauma, are severe, but the absolute number of these cases is small. While the study by Popowski et al, similar to other previous ones, includes a large series of patients, it is still underpowered to demonstrate a difference in these outcomes, with a high probability of a beta-type error 3,4 . We admit that we have difficulties in accepting the conclusions of the authors because, by bringing them to the extreme, it follows that it is better never to know the fetal position; one would then have to stop making this diagnosis even digitally, which to us, frankly, is not logical.…”