Benjamin Byers

Timing of perioperative antibiotics for cesarean delivery: a metaanalysis

OBJECTIVE The purpose of this study was to summarize the available evidence on timing of perioperative antibiotics for cesarean delivery. STUDY DESIGN We searched the literature for studies that compare prophylactic antibiotics for cesarean delivery that are given before the procedure vs at cord clamping. Only randomized controlled trials were included. RESULTS Preoperative administration significantly reduced the risk of postpartum endometritis (relative risk [RR], 0.47; 95% CI, 0.26-0.85; P = .012) and total infectious morbidity (RR, 0.50; 95% CI, 0.33-0.78; P = .002). There was a trend toward lower risk of wound infection (RR, 0.60; 95% CI, 0.30-1.21; P = .15). Preoperative administration of antibiotics did not significantly affect suspected neonatal sepsis that requires a workup (RR, 1; 95% CI, 0.70-1.42), proven sepsis (RR, 0.93; 95% CI, 0.45-1.96), or neonatal intensive care unit admissions (RR, 1.07 95% CI, 0.51-2.24). There was no significant heterogeneity between the randomized controlled trials. CONCLUSION There is strong evidence that antibiotic prophylaxis for cesarean delivery that is given before skin incision, rather than after cord clamping, decreases the incidence of postpartum endometritis and total infectious morbidities, without affecting neonatal outcomes.

Validation of the prediction model for success of vaginal birth after cesarean delivery

OBJECTIVE: To validate a previously developed vaginal birth after cesarean (VBAC) prediction model using a patient cohort different than that from which it was derived. METHODS: We performed a cohort study of all term pregnant women (January 2002–August 2007) with one prior low transverse cesarean delivery attempting a trial of labor. Variables used in the final prediction model (maternal age, prepregnancy body mass index, ethnicity, prior vaginal delivery, prior VBAC, and indication for prior cesarean delivery) were extracted from medical records and used to calculate an individual woman’s predicted VBAC success rate. These rates at the level of the study population then were partitioned into deciles and compared with the actual VBAC rates. RESULTS: Of 545 women who fit the inclusion criteria, 502 had complete data available. A total of 262 (52.2%) had VBAC. The predicted probability of VBAC, as calculated by the regression equation, was significantly higher in those who had a successful trial of labor (median 78.4%, interquartile range 62.1–88.2) than in those who did not (median 59.7%, interquartile range 50.8–75.3, P<.001). The predictive model had an area under the receiver operating characteristic of 0.70 (95% confidence interval 0.65–0.74, P<.001), which was similar to that originally described. The actual VBAC rates did not differ from the predicted rates when the predicted chance of success was less than 50%. Above a 50% predicted success, the achieved success rates were consistently 10–20% lower. CONCLUSION: The published nomogram is predictive of VBAC success. It may help pregnant women contemplating a trial of labor reach a more informed decision. LEVEL OF EVIDENCE: II

Pregnancy outcome after ultrasound diagnosis of fetal intra-abdominal umbilical vein varix

Fetal intra‐abdominal umbilical vein (FIUV) varix is a focal dilatation of the intra‐abdominal portion of the umbilical vein, which has been reported to be associated with intrauterine death and other anomalies. Our aim was to examine our experience with this diagnosis at a single tertiary‐care center and to correlate it with clinical outcome.

The effect of prepregnancy obesity and sFlt-1–induced preeclampsia-like syndrome on fetal programming of adult vascular function in a mouse model

OBJECTIVE The purpose of this study was to test the hypothesis that prepregnancy obesity and soluble fms-like tyrosine kinase-1 (sFlt-1)-induced preeclampsia lead to altered vascular function in the offspring later in life. STUDY DESIGN CD-1 female mice were placed on a low-fat (LF) or high-fat (HF) diet before mating. On day 8 of pregnancy, the HF mice were injected with adenovirus that carried either sFlt-1 (HF sFlt-1) or murine immunoglobulin G2alpha Fc fragment (HF mFc). LF dams received saline solution. After being weaned, all offspring were placed on a standard diet. At 3 months of age, the carotid artery was isolated for in vitro vascular reactivity studies. RESULTS Among male offspring, the response to phenylephrine was significantly lower in the HF sFlt-1 group. The response to serotonin in males and to thromboxane in females was lower in the HF sFlt-1 and HF mFc groups. In females, the HF sFlt-1 and LF groups displayed less relaxation to acetylcholine. The response to phenylephrine was significantly lower in females than males in the HF mFc and LF groups. The response to thromboxane was significantly lower in the HF sFlt-1 females, compared with males. CONCLUSION Prepregnancy obesity and preeclampsia alter fetal programming of adult vascular function. The mechanism is complex and gender specific.

Hyaluronidase modifies the biomechanical properties of the rat cervix and shortens the duration of labor independent of myometrial contractility.

OBJECTIVE To investigate the effect of intracervical hyaluronidase on the biomechanical properties of the cervix and on uterine contractility. STUDY DESIGN Sprague-Dawley rats (n = 33, term day 22) were injected with hyaluronidase (100 IU) or saline solution on day 18 of gestation (n = 8-9/group). On day 21, labor was induced with mifepristone (8 mg/rat). Injection-to-delivery times were recorded. Biomechanical properties of the cervix were assessed using stretch-tension analysis. Myometrial contractility was investigated in response to hyaluronidase (0.2-200 IU/mL), oxytocin (10(-10)M to 10(-5)M), and potassium chloride (60 mM). RESULTS Delivery times were shorter in the hyaluronidase group (P = .03). Cervices of the treated animals showed higher measures of elasticity and plasticity (P = .02 for both). Myometrial sensitivity to hyaluronidase, oxytocin, or potassium chloride was not affected by the cervical application of hyaluronidase (P > .05 for all). CONCLUSION Cervical hyaluronidase treatment shortens labor and alters the biomechanical properties of the cervix, independent of the myometrium.

Pregnancy Complicated by Cyclic Vomiting Syndrome

BACKGROUND: Cyclic vomiting syndrome is a condition that consists of recurrent episodes of vomiting occurring between periods of normal health, with no apparent organic cause of vomiting. We report the sentinel case of pregnancy complicated by preexisting cyclic vomiting syndrome. CASE: A primigravida presented at 8 weeks of gestation with a complaint of protracted vomiting. She had been diagnosed previously with cyclic vomiting syndrome. An extensive workup was performed, and she was admitted for therapy numerous times during her pregnancy. She underwent an indicated preterm delivery for fetal growth restriction, oligohydramnios, and nonreassuring fetal testing. The neonate was discharged to home in stable condition. CONCLUSION: Cyclic vomiting syndrome can complicate pregnancy, and the gravida with cyclic vomiting syndrome may be at risk for pregnancy complications. Increased surveillance may be warranted.

Delivery complicated by postpartum hemorrhage and lower extremity compartment syndrome.

BACKGROUND: Extremity compartment syndrome is a rare surgical complication in which increased intracompartmental pressure threatens the viability of the muscular and nervous tissue. We report a case of a delivery complicated by postpartum hemorrhage and a lower extremity compartment syndrome. CASE: A multigravida in her late 20s was admitted for induction of labor at 41 weeks of gestation. She underwent a cesarean delivery for a nonreassuring fetal heart rate tracing. The delivery was complicated by severe postpartum hemorrhage due to uterine atony, resulting in a cesarean hysterectomy. The patient developed a lower extremity compartment syndrome and underwent an emergent anterior tibial fasciotomy. CONCLUSION: Extremity compartment syndrome is rarely encountered in obstetric care; however, there may be an association with severe postpartum hemorrhage.