Rory Windrim

Oxytocin requirements at elective cesarean delivery: a dose-finding study.

OBJECTIVE: Oxytocin is frequently used by intravenous bolus and infusion to minimize blood loss and prevent postpartum hemorrhage at cesarean delivery. Current dosing regimens are arbitrary whereas large doses may pose a serious risk to the mother. The purpose of this study was to estimate the minimum effective intravenous bolus dose of oxytocin (ED90) required for adequate uterine contraction at elective cesarean in nonlaboring women. METHODS: A randomized, single-blinded study was undertaken in 40 healthy term pregnant women presenting for elective cesarean under spinal anesthesia. Oxytocin was administered by bolus according to a biased coin up-and-down sequential allocation scheme with increments or decrements of 0.5 IU. Uterine contraction was assessed by the obstetrician, who was blinded to the dose of oxytocin, as either satisfactory or unsatisfactory. After achieving sustained uterine contraction, an infusion of 40 mU/min of oxytocin was started. Oxytocin-induced adverse effects and intraoperative complications were recorded and blood loss was estimated. Data were interpreted by parametric analysis based on logistic regression model and nonparametric analyses at 95% confidence intervals (CIs). RESULTS: The ED90 of oxytocin as determined by logistic regression model fitted to the data was estimated to be 0.35 IU (95% CI 0.18–0.52 IU), with nonparametric estimates of 97.1% (95% CI 84.9–99.8%) response rate at 0.5 IU, and 100% (95% CI 92.2–100%) at 1.0 IU. The estimated blood loss was 693 ± 487 mL (mean ± standard deviation). CONCLUSION: The bolus dose of oxytocin used at elective cesarean deliveries in nonlaboring women can be significantly reduced while maintaining effective uterine contraction. Alteration in practice will likely reduce the potential adverse effects of this drug when given in large bolus doses, but may require modification of the techniques to remove the placenta.

Management of monoamniotic twin pregnancies: a case series and systematic review of the literature

Objectives To review the experience of the University of Toronto Perinatal Complex, Ontario, Canada concerning antenatally diagnosed monoamniotic twin pregnancies; and to compare our results with cases reported in the literature with respect to antenatal surveillance and perinatal outcome.

Minimum Oxytocin Dose Requirement After Cesarean Delivery for Labor Arrest

OBJECTIVE: To estimate the minimum effective intravenous dose of oxytocin required for adequate uterine contraction after cesarean delivery for labor arrest. METHODS: A randomized single-blinded study was undertaken in 30 parturients undergoing cesarean deliveries under epidural anesthesia for labor arrest despite intravenous oxytocin augmentation. Oxytocin was administered as a slow intravenous bolus immediately after delivery of the infant, according to a biased coin up-down sequential allocation scheme. After assisted spontaneous delivery of the placenta, the obstetrician, blinded to the oxytocin dose, assessed uterine contraction as either satisfactory or unsatisfactory. Additional boluses of oxytocin were administered as required, followed by a maintenance infusion. Data were interpreted and analyzed by a logistic regression model at 95% confidence intervals. RESULTS: All patients received oxytocin infusions at a mean ± standard deviation of 9.8 ± 6.3 hours before cesarean delivery (maximum infusion dose 10.3 ± 8.2 mU/min). The minimum effective dose of oxytocin required to produce adequate uterine response in 90% of women (ED90) was estimated to be 2.99 IU (95% confidence interval 2.32–3.67). The estimated blood loss was 1,178 ± 716 mL. CONCLUSION: Women requiring cesarean delivery for labor arrest after oxytocin augmentation require approximately 3 IU rapid intravenous infusion of oxytocin to achieve effective uterine contraction after delivery. This dose is 9 times more than previously reported after elective cesarean delivery in nonlaboring women at term, suggesting oxytocin receptor desensitization from exogenous oxytocin administration during labor. Therefore, alternative uterotonic agents, rather than additional oxytocin, may achieve superior uterine contraction and control of blood loss during cesarean delivery for labor arrest. LEVEL OF EVIDENCE: I

Determinants of adverse perinatal outcome in high-risk women with abnormal uterine artery Doppler images

OBJECTIVE The purpose of this study was to evaluate the prognostic role of placental ultrasound imaging at 19-23 weeks of gestation in clinically high-risk women with abnormal uterine artery Doppler (UTAD). STUDY DESIGN Placentas of 60 women with abnormal UTAD were examined at 19-23 weeks of gestation for shape and texture abnormalities. Findings were correlated with clinical outcomes (preterm delivery at <32 weeks of gestation; birth weight <10th percentile [small for gestational age]; preeclampsia/hemolysis, elevated liver enzymes, low platelets; early-onset intrauterine growth restriction with abnormal umbilical artery Doppler; and intrauterine fetal death) and maternal serum screening data. Placental disease was reviewed by 2 perinatal pathologists. RESULTS Women with abnormal placental shape at 19-23 weeks of gestation (n = 28) had higher odds of intrauterine fetal death (odds ratio, 4.5; 95% CI, 1.3-15.6), delivery at <32 weeks of gestation (odds ratio, 4.7; 95% CI, 1.6-14.1]), and intrauterine growth restriction (odds ratio, 4.7; 95% CI, 1.4-15.1]) than did the women with a normal placental shape. Thirty-two of 41 placentas (74%) weighed <10th percentile, and 36 of 43 placentas (83%) had ischemic-thrombotic pathologic condition. There was no association between abnormal placental shape at 19-23 weeks of gestation and placental weight, but 5 of 6 placentas that were <10 cm long were <10th percentile for weight at delivery. There was a poor correlation between measures of ultrasound texture at 19-23 weeks of gestation and the presence of specific lesions at delivery. CONCLUSION Combined abnormal UTAD and placental dysmorphologic condition before fetal viability identifies a subset of women who are at risk of adverse outcomes. Placental size is critical in the determination of the outcome in this situation because of the very high prevalence of destructive lesions, although present methods of placental imaging have significant limitations.

Arterial Embolization for Primary Postpartum Hemorrhage

PURPOSE To evaluate the efficacy and safety of arterial embolization (AE) for treatment of primary postpartum hemorrhage (PPH), and the factors associated with clinical success. MATERIAL AND METHODS A retrospective analysis of all patients undergoing AE for primary PPH at three institutions (N = 43) from 1996 through 2007 was conducted. Patients with an antepartum diagnosis of invasive placenta were excluded from the study. Mean patient age was 31 years +/- 5 (range, 21-40 y). Eighteen women (42%) were primiparous. Delivery details, transfusion requirements, hematology and coagulation results, embolization details, and clinical outcomes were collected. Clinical success was defined as cessation of bleeding without the need for repeat embolization, laparotomy, or hysterectomy after embolization; or death. The Fisher exact test was used to analyze nonparametric data. RESULTS The clinical success rate was 79% (n = 34). Four patients underwent successful repeat embolization. Two of 35 patients who had not undergone hysterectomy before embolization underwent hysterectomy for continued bleeding (without repeat embolization). One underwent hysterectomy 2 weeks after AE for uterine necrosis. One of eight patients who had undergone hysterectomy before AE required a laparotomy for a large retroperitoneal hematoma, and one patient died from cerebral anoxia secondary to hypotension despite repeat embolization. Clinical success was not related to mode of delivery, cause of PPH, transfusion requirements, time from delivery to embolization, or hysterectomy before AE (P > .05). Patients with active extravasation visualized angiographically were more likely to require repeat embolization (five of 13 [38%] vs 0 of 30 without extravasation; P < .01). CONCLUSIONS AE for primary PPH is safe and effective. Repeat embolization may be necessary in patients with active extravasation on angiography.

Cardiac Arrest in Pregnancy: A Scientific Statement From the American Heart Association.

This is the first scientific statement from the American Heart Association on maternal resuscitation. This document will provide readers with up-to-date and comprehensive information, guidelines, and recommendations for all aspects of maternal resuscitation. Maternal resuscitation is an acute event that involves many subspecialties and allied health providers; this document will be relevant to all healthcare providers who are involved in resuscitation and specifically maternal resuscitation.

Screening for Placental Insufficiency in High-risk Pregnancies: Is Earlier Better?

OBJECTIVE To compare a profile of placental function between the first and second trimesters in pregnancies at high risk of adverse perinatal outcomes attributable to placental insufficiency. STUDY DESIGN Prospective cohort study in 61 singleton pregnancies. Uterine artery Doppler and placental morphology (shape and texture) were determined at 11-13(+6) weeks and at 18-23(+6) weeks. First trimester (pregnancy-associated placental protein-A [PAPP-A]) and second trimester (total hCG and alpha fetoprotein [AFP]) serum biochemistry were determined. The two screening periods were compared for the prediction of a range of severe adverse perinatal outcomes (intrauterine growth restriction [IUGR], abruption, severe pre-eclampsia/HELLP syndrome, delivery<32 weeks, or stillbirth). RESULTS Adverse perinatal outcomes occurred in 14 (23%) women; 3 (4.9%) losses<20 weeks, 2 (3.3%) stillbirths>20 weeks, 4 (6.6%) IUGR, 7 (11.5%) severe pre-eclampsia/HELLP syndrome, and 10 (16.4%) deliveries<32 weeks. Abnormal second trimester placental morphology was significantly associated with adverse outcome [+LR: 3.6, 95% CI: 1.3-8.5; -LR: 0.63, 95% CI: 0.36-0.93; p=0.025], as was > or = 1 abnormal second trimester tests [+LR: 5.9, 95% CI: 1.6-24; -LR: 0.68, 95% CI: 0.59-0.89; p=0.005] or > or = 2 abnormal second trimester tests [+LR: 3.6, 95% CI: 1.3-7.7; -LR: 0.58, 95% CI: 0.27-0.94; p=0.035]. No combination of first trimester tests significantly predicted severe adverse perinatal outcomes. A study sample size of 822 women with similar high-risk characteristics would be needed in order to refute the conclusion that present methods of first trimester screening are not inferior to second trimester screening for severe placental insufficiency (p=0.05, power 80%, z-test). CONCLUSIONS In clinically high-risk pregnancies, prediction of adverse perinatal outcomes using placental function testing is more effective in the second compared with the first trimester.

Management of cardiac arrest in pregnancy: a systematic review.

OBJECTIVE To describe the consensus on science pertaining to resuscitation of the pregnant patient. DESIGN Systematic review. DATA SOURCES EMBASE, Ovid MEDLINE, Evidence Based Reviews, American Heart Association library and bibliographies of selected articles. REVIEW METHODS The following inclusion criteria were used: pregnancy and cardiac arrest out of hospital, pregnancy and cardiac arrest in hospital, cardiovascular, respiratory, fetal survival, and pharmacology as they relate to cardiac arrest and resuscitation. Non-English papers, case reports and reviews were excluded. Studies were selected through an independent review of titles, abstracts and full article. Two reviewers independently graded the methodological quality of selected articles. RESULTS 1305 articles were identified and 5 were selected for further review. There were no randomized trials and overall the quality of the selected studies was good. Two studies examined chest compressions on a manikin in left lateral tilt from the horizontal and concluded that although feasible with increasing degrees of tilt forcefulness of the chest compressions decreases. The third study observed the transthoracic impedance was not altered during pregnancy. One case series and one retrospective cohort study reviewed perimortem cesarean section. Both reports concluded that perimortem cesarean section is rarely done within the recommended time frame of 5 min after the onset of maternal cardiac arrest. CONCLUSIONS Usual defibrillation dosages are likely appropriate in pregnancy. Perimortem cesarean section is an intervention which is rarely done within 5 min to optimize maternal salvage from cardiac arrest. Chest compressions in left lateral tilt are less forceful compared to the supine position.

The Early External Cephalic Version (ECV) 2 Trial: an international multicentre randomised controlled trial of timing of ECV for breech pregnancies

Please cite this paper as: Hutton E, Hannah M, Ross S, Delisle M, Carson G, Windrim R, Ohlsson A, Willan A, Gafni A, Sylvestre G, Natale R, Barrett Y, Pollard J, Dunn M, Turtle P, for the Early ECV2 Trial Collaborative Group. The Early External Cephalic Version (ECV) 2 Trial: an international multicentre randomised controlled trial of timing of ECV for breech pregnancies. BJOG 2011;118:564–577.

Effectiveness of cervical cerclage for a sonographically shortened cervix: A systematic review and meta-analysis

OBJECTIVE The purpose of this study was to determine the effectiveness of cerclage for a shortened cervix on transvaginal ultrasound scanning in terms of the rates of preterm delivery and adverse neonatal and maternal outcomes. STUDY DESIGN Pre-MEDLINE and MEDLINE, EMBASE, and the Cochrane Library were searched for human studies that compared cerclage placement to no cerclage on the basis of transvaginal ultrasound findings of a short cervix (< or =2.5 cm). Two authors independently determined eligibility and abstracted data. Meta-analyses were conducted when possible. RESULTS Thirty-five studies were reviewed; 6 studies were eligible and were included in the analysis. There was no statistically significant effect of cerclage on the rates of preterm delivery (<37, <34, <32, and <28 weeks of gestation), preterm labor, neonatal mortality or morbidity, gestational age at delivery, or time to delivery. Birth weight was significantly higher with than without cerclage (P=.004). CONCLUSION The available evidence does not support cerclage for a sonographically detected short cervix. A randomized controlled trial is needed to determine whether this intervention will reduce adverse neonatal outcomes.