David Stamilio

Revisiting the Fetal Loss Rate After Second-Trimester Genetic Amniocentesis : A Single Center's 16-Year Experience

OBJECTIVE: To estimate an institution’s specific fetal loss rate after a second-trimester genetic amniocentesis. METHODS: This is a retrospective cohort study using our prenatal diagnosis database for all pregnant women presenting for care between 1990 and 2006. We compared the fetal loss rate in women who underwent amniocentesis between 15 and 22 weeks of gestation with those women who did not have any invasive procedure and had a live fetus documented on ultrasound examination between 15 and 22 weeks. Only singleton gestations were included. Logistic regression analysis was used to adjust for potential confounders between the groups. RESULTS: Among 58,436 women meeting the inclusion criteria, complete outcome data were available for 51,557 (88%), 11,746 (91%) in the amniocentesis group and 39,811 (87%) in the group that did not have amniocentesis. The fetal loss (miscarriages and intrauterine fetal death) rate in the amniocentesis group was 0.4% compared with 0.26% in those without amniocentesis (relative risk 1.6, 95% confidence interval [CI] 1.1–2.2). Fetal loss less than 24 weeks (including induction for ruptured membranes and oligohydramnios) occurred in 0.97% of the amniocentesis group and 0.84% of the group with no procedure (P=.33). The fetal loss rate less than 24 weeks attributable to amniocentesis was 0.13% (95% CI –0.07 to 0.20%) or 1 in 769. The only subgroup that had a significantly higher amniocentesis attributable fetal loss rate was women with a normal serum screen (0.17%, P=.03). CONCLUSION: The institutional fetal loss rate attributable to amniocentesis is 0.13%, or 1 in 769 at Washington University School of Medicine. The total fetal loss rate was not significantly different from that observed in patients who had no procedure. LEVEL OF EVIDENCE: II

Treatment of localized periodontal disease in pregnancy does not reduce the occurrence of preterm birth: results from the Periodontal Infections and Prematurity Study (PIPS)

OBJECTIVE The purpose of this study was to test whether treating periodontal disease (PD) in pregnancy will reduce the incidence of spontaneous preterm delivery (SPTD) at < or = 35 weeks of gestation. STUDY DESIGN A multicenter, randomized clinical trial was performed. Subjects with PD were randomized to scaling and root planing (active) or tooth polishing (control). The primary outcome was the occurrence of SPTD at <35 weeks of gestation. RESULTS We screened 3563 subjects for PD; the prevalence of PD was 50%. Seven hundred fifty-seven subjects were assigned randomly; 378 subjects were assigned to the active group, and 379 subjects were assigned to the placebo group. Active treatment did not reduce the risk of SPTD at <35 weeks of gestation (relative risk, 1.19; 95% confidence interval [CI], 0.62-2.28) or composite neonatal morbidity (relative risk, 1.30; 95% CI, 0.83-2.04). There was a suggestion of an increase in the risk of indicated SPTD at <35 weeks of gestation in those subjects who received active treatment (relative risk, 3.01; 95% CI, 0.95-4.24). CONCLUSION Treating periodontal disease does not reduce the incidence of SPTD.

Short interpregnancy interval: risk of uterine rupture and complications of vaginal birth after cesarean delivery.

OBJECTIVE: To investigate whether short or long interpregnancy interval is associated with uterine rupture and other major maternal morbidities in women who attempt vaginal birth after cesarean delivery (VBAC). METHODS: We performed a secondary analysis of a U.S. multi-center, record-based, retrospective cohort study of 13,331 pregnant women, identified by a validated International Classification of Disease, 9th Revision, code search, with at least one prior cesarean delivery, who attempted VBAC between 1995 and 2000. We performed univariable and multivariable logistic regression analyses to evaluate the association between long or short interpregnancy interval and three maternal outcomes: 1) uterine rupture, 2) composite major morbidity (including rupture, bladder or bowel injury, and uterine artery laceration), and 3) blood transfusion. We evaluated short interpregnancy interval with cutoffs at less than 6, less than 12, and less than 18 months between prior delivery and conception and defined long interval as 60 months or more. RESULTS: A total of 128 cases (0.9%) of uterine rupture occurred, and 286 (2.2%), 1,109 (8.3%), 1,741 (13.1%), and 2,631 (19.7%) women had interpregnancy intervals of less than 6, 6–11, 12–17, and 60 months or more, respectively. An interval less than 6 months was associated with increased risk of uterine rupture (adjusted odds ratio [aOR] 2.66, 95% confidence interval [CI] 1.21–5.82), major morbidity (aOR 1.95, 95% CI 1.04–3.65), and blood transfusion (aOR 3.14, 95% CI 1.42–6.95). Long interpregnancy interval was not associated with an increase in major morbidity. CONCLUSION: Short interpregnancy interval increases risk for uterine rupture and other major morbidities twofold to threefold in VBAC candidates. LEVEL OF EVIDENCE: II

Cerebroplacental Doppler Ratio and Adverse Perinatal Outcomes in Intrauterine Growth Restriction Evaluating the Impact of Using Gestational Age–Specific Reference Values

The purpose of this study was to compare the impact of using gestational age–specific reference levels of the cerebroplacental Doppler ratio (CPR) with categorical threshold in the prediction of adverse perinatal outcomes in growth‐restricted pregnancies.

Staples compared with subcuticular suture for skin closure after cesarean delivery: a systematic review and meta-analysis.

OBJECTIVE: To estimate whether staples or subcuticular suture closure is associated with a higher risk of wound complications when used for transverse skin incisions after cesarean delivery. DATA SOURCES: A systematic review and meta-analysis were performed through electronic database searches (MEDLINE, Cochrane, and Trial Registries). METHODS OF STUDY SELECTION: We searched electronic databases from 1966 to September 2010 for randomized controlled trials (RCTs) and prospective cohort studies comparing staples to subcuticular sutures after cesarean delivery. The primary outcome was occurrence of a wound complication (infection or separation). Secondary outcomes were components of the composite outcome, operating time, postoperative pain, cosmesis, and patient satisfaction. Heterogeneity was assessed using the &khgr;2 test for heterogeneity, and I2 test. Pooled odds ratios (ORs) were calculated using a fixed-effects model. We assessed publication bias using funnel plots and Egger test. RESULTS: Six studies met inclusion criteria: five RCTs and one prospective cohort study. Staple closure (n=803) was associated with a twofold higher risk of wound infection or separation compared with subcuticular suture closure (n=684) (13.4% versus 6.6%, pooled OR 2.06, 95% confidence interval [CI] 1.43–2.98). The number needed to harm associated with staple closure was 16. The increased risk persisted when analysis was limited to the RCTs (OR 2.43, 95% CI 1.47–4.02). There was no evidence of significant statistical heterogeneity among studies (&khgr;2=0.74, P=.327, I2=13.7%) or publication bias (Egger test, t=−0.86, P=.439). Staple closure was associated with shorter duration of surgery, whereas the two techniques appeared equivalent overall with regard to pain, cosmesis, and patient satisfaction. CONCLUSION: Staple closure is faster to perform but associated with a higher risk of wound complications.

Higher maximum doses of oxytocin are associated with an unacceptably high risk for uterine rupture in patients attempting vaginal birth after cesarean delivery

OBJECTIVE The objective of the study was to more precisely estimate the effect of maximum oxytocin dose on uterine rupture risk in patients attempting vaginal birth after cesarean (VBAC) by considering timing and duration of therapy. STUDY DESIGN A nested case-control study was conducted within a multicenter, retrospective cohort study of more than 25,000 women with at least 1 prior cesarean delivery, comparing cases of uterine rupture with controls (no rupture) while attempting VBAC. Time-to-event analyses were performed to examine the effect of maximum oxytocin dose on the risk of uterine rupture considering therapy duration, while adjusting for confounders. RESULTS Within the nested case-control study of 804 patients, 272 were exposed to oxytocin: 62 cases of uterine rupture and 210 controls. Maximum oxytocin ranges above 20 mU/min increased the risk of uterine rupture 4-fold or greater (21-30 mU/min: hazard ratio [HR] 3.92, 95% confidence interval [CI], 1.06 to 14.52; 31-40 mU/min: HR 4.57, 95% CI, 1.00 to 20.82). CONCLUSION These findings support a maximum oxytocin dose of 20 mU/min in VBAC trials to avoid an unacceptably high risk of uterine rupture.

False-positive 1-hour glucose challenge test and adverse perinatal outcomes.

OBJECTIVE: To determine whether a false-positive 1-hour glucose challenge test (GCT) is associated with perinatal complications. METHODS: We performed a retrospective cohort study of 1825 eligible pregnant women among a cohort of 1998 patients. Patients were screened for gestational diabetes mellitus (GDM) with the 1-hour 50-g GCT at 24–28 gestational weeks. A false-positive GCT was defined as a result greater than or equal to 135 mg/dL followed by a normal 3-hour glucose tolerance test (GTT). We compared the negative GCT and false-positive GCT cohorts for a composite perinatal outcome variable that included fetal macrosomia, antenatal death, shoulder dystocia, chorioamnionitis, preeclampsia, intensive care nursery admission, and postpartum endometritis. Secondary outcomes included cesarean delivery and each component variable of the composite. Unadjusted, stratified, and multiple logistic regression analyses were used to investigate the association between a false-positive GCT and the development of perinatal complications. RESULTS: We identified 164 patients with a false-positive GCT and 50 patients with GDM. The false-positive GCT cohort on average was older, of higher parity, had a higher body mass index, and more frequently had chronic hypertension, sickle cell trait, and elevated midtrimester human chorionic gonadotropin levels. The false-positive GCT cohort more frequently had adverse perinatal outcomes, including the composite perinatal outcome (odds ratio [OR] 5.96, 95% confidence interval [CI] 1.47, 24.16), macrosomia greater than 4500 g (OR 3.66, 95% CI 1.30, 10.32), antenatal death (OR 4.61, 95% CI 0.77, 27.48), shoulder dystocia (OR 2.85, 95% CI 1.25, 6.51), endometritis (OR 2.18, 95% CI 1.03, 4.63), and cesarean delivery (OR 1.76, 95% CI 0.99, 3.14). CONCLUSION: A false-positive GCT is an independent risk factor for adverse perinatal outcomes. LEVEL OF EVIDENCE: II-2

Predicting failure of a vaginal birth attempt after cesarean delivery.

OBJECTIVE: To identify a group of clinical factors that could be used to accurately predict failure in women attempting vaginal birth after cesarean (VBAC). METHODS: We conducted a planned secondary analysis of a retrospective cohort study of women who were offered VBAC from 1996 to 2000 in 17 community and university hospitals. We collected information about maternal history and outcomes of the index pregnancy. We used univariable and multivariable statistical methods to develop a multivariable prediction model for the outcome of VBAC failure. RESULTS: A total of 13,706 patients attempted VBAC, with a failure rate of 24.5%. Six variables were significantly associated with VBAC failure in our final logistic regression model: gestational age at delivery, maternal age, maternal race, labor type (spontaneous, augmented, or induced), history of vaginal delivery, and cephalopelvic disproportion or failed induction (combined variable) as prior cesarean indication. The area under the receiver operating characteristics curve is 0.717. To achieve a sensitivity of approximately 75%, a false-positive rate of approximately 40% would result. CONCLUSION: Our results indicate that significant clinical variables (prelabor and labor) cannot reliably predict VBAC failure. LEVEL OF EVIDENCE: II

Evaluating the Rate and Risk Factors for Fetal Loss After Chorionic Villus Sampling

OBJECTIVE: To estimate the fetal loss rate in our center and evaluate the risk factors associated with such losses after chorionic villus sampling (CVS). METHODS: This is a retrospective cohort study including all women undergoing chorionic villus sampling and a control group that had no invasive procedure at a single center over a 16-year period. Fetal loss was defined as any loss before 24 weeks of gestation. Univariable and multiple logistic regression analyses were used to compare pregnancies resulting in fetal loss to those without a loss and to adjust for potential confounders between the groups. RESULTS: Of 5,243 women who had CVS who were compared with 4,917 women seen before 14 weeks who had no invasive procedure, there were 138 (2.7%) fetal losses before 24 weeks of gestation in the CVS group compared with 161 (3.3%) in the control group (relative risk 0.80, 95% confidence interval, 0.64–1.0). The difference in loss rate of –0.7% (95% confidence interval, –0.02 to 1.3) between the CVS group and those who had no procedure was not statistically significant at P<.05. The significant risk factors for fetal loss were African-American maternal race, at least two aspirations/needle insertions, heavy bleeding during CVS, maternal age younger than 25 years, and gestational age at performing CVS before 10 weeks. CONCLUSION: The estimated fetal loss rate after CVS was not significantly different from the group that had no procedure. Significant predictors of fetal loss after CVS were identified, but the accuracy of the final model for predicting fetal loss was only modest. LEVEL OF EVIDENCE: II

A cost-effectiveness analysis of prenatal screening strategies for Down syndrome.

Objective: To evaluate which Down syndrome screening strategy is the most cost-effective. Methods: Using decision-analysis modeling, we compared the cost-effectiveness of 9 screening strategies for Down syndrome: 1) no screening, 2) first-trimester nuchal translucency (NT) only, 3) first-trimester combined NT and serum screen, 4) first-trimester serum only, 5) quadruple screen, 6) integrated screening, 7) sequential screening, 8) integrated serum only, or 9) maternal age. Costs included cost of tests and resources used for raising a child with Down syndrome. One-way and multiway sensitivity analyses were performed for all model variables. The main outcome measures were cost per Down syndrome case detected, rate of delivering a liveborn neonate with Down syndrome, and rate of diagnostic procedure–related pregnancy loss for each strategy. Results: Sequential screening detected more Down syndrome cases compared with the other strategies, but it had a higher procedure-related loss rate. Integrated serum screening was the most cost-effective strategy. Sensitivity analyses revealed the model to be robust over a wide range of values for the variables. The addition of the cost of genetic sonogram to the second-trimester strategies resulted in first-trimester combined screening becoming the most cost-effective strategy. Conclusion: Within our baseline assumptions, integrated serum screening was the most cost-effective screening strategy for Down syndrome. If the cost of nuchal translucency is less than