Does baby’s position matter in pregnancy and can we do anything about it?
Catie Mehl of Columbus Birth & Parenting and Angela Horn from Tuscon doulas recently published blog posts about malposition.
Does baby’s position matter in labor? (Part 1 and 2)
These two women presented on this topic at the 2015 ProDoula Instilling Strength Conference. Their presentation, “OP Babies: A Real Pain in the Ass,” examined common misunderstandings of OP babies and back labor and examined current body of research on these topics.
I would argue that the post might have benefitted from some literature searching support as there are many more studies looking at malposition and posterior presentation that have been published in the past twenty years (a quick search on google scholar shows these number into the thousands) than the twenty they read.
In Part 1 (Catie Mehl of Columbus Birth & Parenting) states:
You can’t prevent a posterior baby and start and stop labor is not because baby is OP
There have been few studies that directly looked at the association of fetal position and length or prevalence of prodromal labour. We do know that women that present to their chosen place of birth before active labour are more likely to go on to have more interventionsand prolonged latent phase (as well as PROM) has found to be a predictor of failed induction.
I have previously discussed this in my blog post here:
An OP position might not stop someone going into labour but it is associated with prolonged pregnancy and we also know that lack of fetal head engagement predicts prolonged pregnancy. [4 5]And that fetal head above the inter-spinal diameter and poor fetal head-to-cervix contact are associated with dystocia in labour. Descent of fetal head is correlated to dilatation of the cervix, and cervix dilatation < 4 cm at admission was associated with an increased risk of dystocia. Women admitted with little cervical dilatation may have unbearably painful contractions. High risk of dystocia in women admitted in early labour has also been found in many studies 
As the blog author states, OP babies tend to be deflexed and another study by Ashour et al. found that in women undergoing induction of labour, prediction of outcome can be provided by determining sonographically the preinduction cervical length, occipital position and degree of flexion of the head which were superior to Bishop score in predicting successful induction.
So this means that OP (and other malpositions) effect flexion and fetal head engagement which can lead to prolonged pregnancy and long latent phase/prodromal labour which is all in turn associated with longer labour more intervention in labour, failed induction, instrumental and CS delivery.
The authors then go on to state: “There is a belief that a person can prevent an OP baby by maintaining specific postures and avoiding others during pregnancy.”
I would agree that the evidence supporting the beliefs that OP is always a problem in labour and is also the only malposition that can effect starting labour and progress of labour is false.
My own position is that whether a malposition is a problem for an individual diad will depend on many factors-
- Pelvis shape/size
- Uterine ligaments
- Baby size
- Baby position (this can also encompass flexion (chin tucking) asyncliticism and arms above the head
- Mothers health both pre pregnancy and in pregnancy (diet and exercise)
- Mothers mobility in labour
- Mothers pain relief in labour
There is no one ideal position. Flexion (which can be effected by fetal position), asyncliticism (Asynclitism is one of the most frequent malpositions of the fetal head, occurring during both first and second stage of labor. Any fetal head position may be associated. OT position is frequently associated with asyncliticism. If the fetal head does not rotate at mid pelvis (spines) to OA or OP this may lead to deep transverse arrest) compound arms, fetal size and position (of both head and trunk) can all effect labor.
There is also little current evidence that it is possible to prevent malposition prior to labour (and as the authors state, the majority of malpositioned babies, rotate and can be born vaginally). Although we do know that the longer a baby stays in a malposition in labour, the more likely it is for them to stay that way. but…
“no evidence of effect” is not “evidence of no effect”
The evidence for maternal posturing in pregnancy to prevent malposition is currently weak. Is this because the right studies haven’t been done yet? Many of the studies finding no effect in pregnancy randomised women to interventions like Hands and knees rocking with pelvic rocking from 37 weeks (for 10 minutes twice daily ) had no effect on POP or outcomes and a Cochrane review concluded that use of hands and knees position for 10 minutes twice daily to correct occipito-posterior position of the fetus in late pregnancy cannot be recommended as an intervention
Those of us that work with women with malposition in pregnancy might see these interventions that have been studied as too little to change outcomes.
There is evidence of the benefit of general fitness in pregnancy on improving outcomes, and also birth ball use (it has been postulated that vigorous circles on the birth ball may aid flexion of the fetal head). A physical exercise program during pregnancy is associated with a shorter first stage of labor
I agree that the evidence is not strong that back pain in labour is due to fetal malposition (at least not always) but excessive pain, especially in early labour is associated with dystocia (which is associated with malposition) and more frequent breakthrough pain during epidural analgesia is common in dysfunctional labors  a recent study found that mothers who experience high levels of pain during pregnancy (lower back and pelvic pain which the authors postulate may be due to occurrence of malpositioning of the fetus during pregnancy.) are at increased risk of complications during labourand the authors go on to say that further investigation into the role of pain during pregnancy, fetal position and birth outcomes is necessary.
There is a large body of evidence that malposition effects women’s pregnancies, and can lead to pain in pregnancy, prolonged pregnancy, longer pre-labour and birth outcomes. There is currently little research that has found evidence of an effect of interventions on preventing malposition. OP is not the only malposition that can effect pregnancy and labour outcomes this is partly due to paucity of rigorous studies that use the range of methods currently being utilised by midwives and doulas..[18-21]. There is evidence for exercise in pregnancy to improve birth outcomes and reduce length of labour, pain and need for augmentation, assisted delivery and CS
I will address Part 2 of the blog (Does baby’s position matter in labour and can we do anything about it?) in a subsequent post
- Spiby H, Green J, Renfrew M, et al. Improving care at the primary/secondary interface: a trial of community-based support in early labour. The ELSA trial. Report for the National Co-ordinating Centre for NHS Service Delivery and Organisation R&D (NCCSDO) 2008
- Khan NB, Ahmed I, Malik A, et al. Factors associated with failed induction of labour in a secondary care hospital. JPMA-Journal of the Pakistan Medical Association 2012;62(1):6
- Fitzpatrick M, McQuillan K, O’Herlihy C. Influence of persistent occiput posterior position on delivery outcome. Obstetrics & Gynecology 2001;98(6):1027-31
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- Ashour ASA, ABDELLA RM, GHAREEB HO, et al. Preinduction ultrasonographic measurements as a predictor of successful induction of labor in prolonged pregnancy in primigravidas. 2013
- Malvasi A, Barbera A, Di Vagno G, et al. Asynclitism: a literature review of an often forgotten clinical condition. The Journal of Maternal-Fetal & Neonatal Medicine 2014(0):1-5
- Malvasi A, Bochicchio M, Vaira L, et al. The fetal head evaluation during labor in the occiput posterior position: the ESA (evaluation by simulation algorithm) approach. The Journal of Maternal-Fetal & Neonatal Medicine 2014;27(11):1151-57
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