Long term backache after childbirthBMJ 1996; 313 doi: http://dx.doi.org/10.1136/bmj.313.7059.755a (Published 21 September 1996) Cite this as: BMJ 1996;313:755
Potential confounding by obstetric malposition was not considered
- Imogen F D Stephens, Registrar in public health medicine
EDITOR,—Epidural analgesia forms an important part of the clinical management of labour. Robin Russell and colleagues' study showing a lack of association between epidural analgesia during labour and the development of new backache after childbirth should prove reassuring to clinicians and prospective parents alike.1
The authors do not, however, seem to have considered the potential confounding effect of obstetric malposition, in particular the occipitoposterior position, in both pregnancy and labour. It has been estimated that at least a fifth of women start labour with the fetal head in the occipitoposterior position.2 This malposition can cause severe back pain both in labour and in the later stages of pregnancy. The occipitoposterior position is recognised as a common cause of prolonged and dysfunctional labour. Certain pelvic shapes seem to predispose to a recurrence of this malposition in subsequent pregnancies.
Pregnant women whose fetus remains in the occipitoposterior position, and those who enter labour with the fetus in this position, are more likely to experience back pain and to have a longer labour. They are therefore more likely to request epidural analgesia in labour. Indeed, many obstetricians regard an epidural block as an integral part of the management of dysfunctional labour when the fetal head is in the occipitoposterior position. The association between these two relatively common obstetric phenomena may therefore contribute to an apparent relation between obstetric analgesia and back pain.
More information is needed on the proportion of pregnancies and labours complicated by the fetal head being in the occipitoposterior position so that the contribution of this malposition to both acute and chronic back pain after childbirth can be assessed.