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5 - OBSTETRIC TRAUMA ASSOCIATED WITH OPERATIVE VAGINAL DELIVERY, BY PELVIC STATION, COMPARED WITH CESAREAN DELIVERY IN THE SECOND STAGE OF LABOUR

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OBSTETRIC TRAUMA ASSOCIATED WITHOPERATIVE VAGINAL DELIVERY, BY PELVIC STATION, COMPARED WITH CESAREANDELIVERY IN THE SECOND STAGE OF LABOUR

G. M. MURACA1, Y.SABR 2, S. LISONKOVA 1, A. SKOLL 1,G. W. CUNDIFF 1, K. JOSEPH 1;
1Univ.of British Columbia, Vancouver, Canada, 2King Saud Univ.,Riyaad, Saudi Arabia.

Introduction: There is currentlyinsufficient evidence regarding the maternal safety of operativevaginal versus cesarean delivery in the second stage of labor.1However, the recent increase in cesarean delivery rates in manyindustrialized settings has led to operative vaginal delivery beingadvocated as a strategy to curb the rising frequency of cesareandelivery.2,3
Objective: To quantify rates ofobstetric trauma associated with operative vaginal delivery, bypelvic station, compared with cesarean delivery in the second stageof labor, and to determine whether these associations differ bypelvic station.
Methods: We carried out a population-based,retrospective cohort study among all hospital deliveries in Canadafrom 2003 to 2013 with data obtained from the Canadian Institute forHealth Information. The study population included all full termoperative vaginal and cesarean deliveries with a prolonged secondstage of labor. The primary outcome was composite obstetric traumaincluding severe perineal laceration (3rd, 4th-degree),cervical laceration, high vaginal laceration, injury to pelvicorgan/joint, pelvic hematoma, and extension of uterine incision.Deliveries were stratified by indication for operative delivery(dystocia/fetal distress). Logistic regression was used to estimateadjusted odds ratios (AOR) and 95% confidence intervals (CI) aftercontrolling for maternal age, parity, birth weight, previous cesareandelivery, maternal province of residence, and year of birth.
Results:The maternity population had an operative vaginal delivery rate of11.2% and cesarean rate of 26.2%. The study population included58,819 deliveries; 36,700 with dystocia and 22,119 with fetaldistress. Among women with dystocia, forceps and vacuum deliverieswere associated with higher rates of obstetric trauma compared withcesarean delivery (forceps AOR 5.34, 95% CI 4.85-5.88; vacuum AOR2.89, 95% CI 2.63-3.18). Among deliveries with fetal distress,obstetric trauma was similarly increased following operative vaginaldelivery (forceps AOR 4.23, 95% CI 3.78-4.73; vacuum AOR 2.28, 95% CI2.04-2.55). For deliveries with dystocia, the associations betweenforceps and vacuum delivery and obstetric trauma were modified bypelvic station. There was a linear increase in the effect of vacuumdelivery on obstetric trauma (AOR at outlet station 2.36, AOR at lowstation 2.91 and AOR at mid-pelvic station 3.35, P for linear trendin OR<0.0001; Figure 1).

Rates of severe perineal lacerationswere high (11% to 25%) among all operative vaginal deliveries,regardless of pelvic station (Figure 2).


Conclusions: Operativevaginal delivery is associated with significantly higher rates ofobstetric trauma when second stage is prolonged. Encouragingoperative vaginal delivery as an alternative to cesarean delivery islikely to increase obstetric trauma. Women should be counselled inthe antepartum period about the relative risks and benefits ofoperative vaginal and cesarean delivery.
References: 1.Cochrane Database Syst Rev 2012;10:005545. 2. J Obstet Gynaecol Can2016;38:627-35. 3. Am J Obstet Gynecol 2014;210:179-93.