cephalic presentation

cephalic presentation

Cephalic Presentation: Promoting Optimal Fetal Positioning

1. Understanding Cephalic Presentation

When describing fetal presentation, clinicians and midwives are primarily interested in the position of the baby’s head in relation to the mother’s pelvis, and more specifically the baby’s occiput (or back of the head). Cephalic presentation, the most common fetal presentation, occurs when the occiput is the presenting part. This can result in the baby being in a left occiput anterior, left occiput transverse, occiput posterior, or right occiput anterior position. Optimal fetal positioning can be seen as when the baby is in a left occiput anterior position, and hence facing the mother’s spine. This is the best position for the baby to negotiate the maternal pelvis and pelvic floor and to be born, minimizing the chance of intervention in the birth process. Left occiput transverse positions can often change into a LOA position during labor itself, particularly with the use of various positional techniques. OP and right occiput positions are also not seen as favorable positions for descent and birth. So concisely, the most ideal presentation for a baby to be born is with its head down and its back facing its mother’s belly.

2. Importance of Optimal Fetal Positioning

The way a baby is positioned in the womb can have huge implications for its birth, and is increasingly recognised as a significant factor in determining the safety, ease, and outcomes of labour. In the same way that the baby’s head engages in the pelvis before labour commences, so the baby must move into an optimal position for the best, easiest, and safest birth. Optimal Fetal Positioning (OFP) is the process of the baby moving into the best position for birth. Usually, this is with the back of the baby’s head on the front of the mother’s cervix, the cephalic position. The Occipito Posterior (OP) position is less than ideal as the widest part of the baby’s head is not on the cervix, and the OP baby must rotate to the OA (Occipito Anterior) position in order to be born. If the baby is in a breech or sideways position, there are more serious implications for childbirth and the baby may not be able to be born naturally. Research has shown that there are a number of factors that affect the way a baby lies in the womb. Attention to these factors and working to assist the baby into an optimal position can have a profound effect on birth. Midwives and doulas who incorporate OFP into their practice have reported good results in women having easier, shorter labours, a lower caesarean rate, and less need for forceps and ventouse deliveries. By working on optimal fetal positioning throughout pregnancy, it is hoped this will help decrease the rates of less than ideal fetal positions and thus lead to fewer birth complications and lower rates of medical intervention. Optimal fetal positioning has also been reported to have a significant effect on the length of labour with evidence that babies who are in the posterior position at the onset of labour tend to create a longer, slower labour.

3. Techniques for Encouraging Cephalic Presentation

Basic techniques for instructing patients on cephalic presentation: Hands and Knees position. Placing the pelvis higher than the knees in this position takes pressure off the sacrum and pelvis, enabling the baby to do a somersault into the right position. Acupressure/Acupuncture. Chinese medicine holds that a breach baby is often a result of imbalanced energy of the mother, and manipulation of the little toe meridian has been known to encourage cephalic presentation of the fetus. In fact, there are over 150 points on the body that may be used to facilitate a smooth birth and many reports of success among alternative health practitioners. Moxibustion. The herb moxa (mugwort) is used to warm a particular area or point. The traditional Chinese version where an acupuncture needle is inserted and a small amount of moxa burned on the handle is contraindicated in pregnancy. The version used by acupuncturists comes in a stick (like a big cigar) which they burn and wave around a point, and a practitioner would often teach the patient to have her partner do this to the appropriate point for 10 minutes per side, twice a day. The benefit may not only be in encouraging the baby to turn, but also in promoting relaxation and visualization of baby being head down.

4. Benefits of Cephalic Presentation for Mother and Baby

An aligned head-down (cephalic) presentation for birth is important for three reasons. Because over 85% of infants are born in the occiput anterior position, we know that optimal fetal positioning fosters labor progress, and this is the usual position for the best fit through the pelvis. The probability for spontaneous vaginal birth is highest when the baby is OA or OT. If the baby is in a posterior position, asynclitism occurs when the fetal head becomes wedged in the mother’s pelvis and is unable to adequately rotate or descend during labor. This can happen when there is malpresentation of the head or the diameter of the baby’s head is too large to fit through the pelvis. When this occurs, labor progress stops as contractions become less effective in dilating the cervix and helping the baby further descend. If not resolved, asynclitism can result in a stalled labor, which greatly increases the likelihood of a cesarean birth. A baby who is overly deflexed or extended can also hinder the descent into the pelvis and passage through the cervix. This inability to negotiate the pelvis is also a contributing factor to a cesarean birth. In his book, “Understanding Diagnostic Tests in the Childbearing Year,” Plymire states, “the mother experiences significantly more difficulty delivering an extended or deflexed head by an order of 38 times in regard to a normal presentation.” Being that the most common reason for a c-section today is “failure to progress,” it is clear that promoting optimal fetal positioning and decreasing the chance for complications due to a poorly aligned presenting part is in the best interest of the mother and baby.

5. Conclusion: Promoting Healthy Birth Outcomes

The current understanding of cephalic presentation from both a midwifery and mainstream medical perspective has developed out of a desire to foster the optimal conditions for safe and efficient birthing. The goal of all care providers is a healthy mother and healthy baby. Identification of the factors which predispose a baby to cephalic malpresentation is still an inexact science. Similarly, there are various suggestions on how to turn a breech baby to a head-down position. While some of these techniques are easy to implement, others require a referral to a specialist or are not covered by current funding models. An evaluation of these options in terms of their safety, effectiveness, cost, and acceptability to pregnant women would be of great value. Randomized controlled trials need to be carried out to test the safety and effectiveness of the various options for turning a breech baby. This should be balanced against the potential for some options to cause stress and discomfort to the baby or harm the mother. In the absence of firm evidence on the cause of cephalic malpresentation, there are cultural factors that can be modified to foster optimal fetal positioning. Women need to be educated about the implications of fetal position on the ease and safety of their birth. This can help to dispel the myth that a posterior or asynclitic baby is impossible to deliver vaginally and reduce the level of anxiety experienced by women who find out their baby is not head down. This, in turn, may impact their level of confidence in the birthing process, which O’Sullivan (2006) identified as a key factor influencing a woman’s sense of control and security during birth. A qualitative study involving women who have experienced a breech birth could provide useful information on how best to support and inform women in this situation.