Occiput posterior fetal head position: Not just vacuum assisted deliveries but primary prevention

Abstract

To the Editors: We read the interesting article by Wu et al.1Wu J.M. Williams K.S. Hundley A.F. Connolly A.M. Visco A.G. Occiput posterior fetal head position increases the risk of anal sphincter injury in vacuum-assisted deliveries.Am J Obstet Gynecol. 2005; 193: 525-529Abstract Full Text Full Text PDF PubMed Scopus (57) Google Scholar These authors in their study find out that occiput posterior head position (OP) in vacuum-assisted deliveries has an increased rate of anal sphincter injury (41% in OP vs 22% in occiput anterior head position [OA]). We know from literature that both OP and vacuum-assisted deliveries have an increased rate of anal sphincter injury.1Wu J.M. Williams K.S. Hundley A.F. Connolly A.M. Visco A.G. Occiput posterior fetal head position increases the risk of anal sphincter injury in vacuum-assisted deliveries.Am J Obstet Gynecol. 2005; 193: 525-529Abstract Full Text Full Text PDF PubMed Scopus (57) Google Scholar In our study we find that OP in labor increases the rate of cesarean sections (CSs) and operative deliveries (ODs) when compared with a comparable population in OA (monofetal, cephalic, physiologic at term) (CS 54% vs 11.6%, P < .05, respectively; OD 12% vs 2.3%, P < .05, respectively).2Strolego F. Londero F. Occipite posteriore e distocia meccanica.Un problema clinico. Riv Ostetric Ginecol Pratica Med Perinat. 2005; 20: 7-11Google Scholar We find in OP that 58% of ODs and CSs are due to mechanic dystocia before 4 cm of dilatation and after 4 cm to cardiotocographic alterations (early, variable decelerations in 40%).2Strolego F. Londero F. Occipite posteriore e distocia meccanica.Un problema clinico. Riv Ostetric Ginecol Pratica Med Perinat. 2005; 20: 7-11Google Scholar The existence of more complications than in OA occurring during labor and delivery give to OP importance as a pathologic position. What does it mean for the authors avoiding vacuum-assisted delivery in OP? In their article they express the idea of treating otherwise this situation to decrease the anal sphincter damage, because the long-term morbidity and the cost correlated to this disease. They do not propose solutions. The immediate idea for avoiding vacuum and forceps use is selecting these cases for CS, but other observations are necessary. First, OPs are more frequent in nulliparous women. Second, before performing a CS we have to think in a second pregnancy about the increased risk of adverse perinatal outcomes and the higher rate of maternal adverse events in a trial of labor compared with another CS.3Landon M.B. Hauth J.C. Leveno K.J. Spong C.Y. Leindecker S. Varner M.W. et al.for the National Institute of Child Health and Human Development Maternal-Fetal Medicine Units NetworkMaternal and perinatal outcomes associated with a trial of labor after prior cesarean delivery.N Eng J Med. 2005; 351: 2581-2589Crossref Scopus (936) Google Scholar Because of these reasons we consider a prevention opportunity. When we have diagnosed an OP at term of gestation, we can consider suggesting the following behaviors4Sutton J. Occipito-posterior positioning and some ideas about how to change it!.Practising Midwife. 2000; 3: 20-22PubMed Google Scholar: to prefer specific positions (prone, by one side) instead of others (supine, seated); to sleep by one side (right for OP in right position and left for left position); to be more active during the day, to put a pillow above the buttocks, so they will be higher than abdomen; or not sitting with knees higher than pelvis. We are aware of no evidence. The most reliable studies about prevention demonstrate that there is no reason to suggest this behavior.5Kariminia A. Chamberlain M.E. Keogh J. Shea A. Randomised controlled trial of effect of hands and knees posturing on incidence of occiput posterior position at birth.BMJ. 2004; 328: 490-494Crossref PubMed Scopus (31) Google Scholar But we think these studies are limited just to some exercises and to a limited time of exposure. In our considerations, the prevention opportunity is a good possibility because of low costs and easy applicability. We hope to obtain in the future more solutions with statistical significance because OP is a clinical problem particularly for male fetuses of elevated weight and over 40 weeks of pregnancy.2Strolego F. Londero F. Occipite posteriore e distocia meccanica.Un problema clinico. Riv Ostetric Ginecol Pratica Med Perinat. 2005; 20: 7-11Google Scholar