Incidence of fetal anomalies after incomplete anatomic surveys between 16 and 22 weeks.

OBJECTIVE: Midtrimester fetal anatomic surveys by ultrasound are a standard obstetrical practice. As technology has improved, anatomic surveys are increasingly performed at earlier gestational ages. Ultrasound's ability to detect anomalies may be limited before 20 weeks, thereby increasing the likelihood of an incomplete survey. We sought to determine factors contributing to incomplete sonograms and the likelihood of fetal anomalies identified on subsequent examinations. STUDY DESIGN: We conducted a retrospective case-control study by comparing incomplete anatomic surveys from 2004 to 2009 at the University of Washington to an identical number of examinations where the study was completed successfully. Patients with multiple gestations, anomalies, and surveys performed outside of the range of 16 to 22 weeks were excluded. RESULTS: One thousand thirty incomplete and complete surveys were identified. Maternal body mass index and early gestational age less than 18 weeks were associated with incomplete examinations. Incomplete visualization of the cardiac structures and spine were the most common reasons for an incomplete survey. Almost 40% of these incomplete examinations were completed on subsequent ultrasound (mean number of ultrasounds: 2). Five percent had a fetal anomaly or aneuploidy marker identified on subsequent ultrasound. CONCLUSION: Incomplete anatomic surveys were associated with gestational age less than 18 weeks and maternal habitus. Five percent of patients had anomalies or aneuploidy markers on subsequent scans, and the majority of these were cardiac defects were cardiac defects. No spine abnormality was detected in any fetus with incomplete visualization of the spine with normal intracranial anatomy. These data that indicate the optimal timing for anatomic survey is beyond 18 weeks and more than 20 weeks for patients with body mass index greater than 30 kg/m and highlight the importance of subsequent ultrasounds to complete anatomy surveys.

The preterm birth syndrome: issues to consider in creating a classification system.

A comprehensive classification system for preterm birth requires expanded gestational boundaries that recognize the early origins of preterm parturition and emphasize fetal maturity over fetal age. Exclusion of stillbirths, pregnancy terminations, and multifetal gestations prevents comprehensive consideration of the potential causes and presentations of preterm birth. Any step in parturition (cervical softening and ripening, decidual-membrane activation, and/or myometrial contractions) may initiate preterm parturition, and should be recorded for every preterm birth, as should the condition of the mother, fetus, newborn, and placenta, before a phenotype is assigned.

The preterm birth syndrome: a prototype phenotypic classification.

Preterm birth is a syndrome with many causes and phenotypes. We propose a classification that is based on clinical phenotypes that are defined by ≥ 1 characteristics of the mother, the fetus, the placenta, the signs of parturition, and the pathway to delivery. Risk factors and mode of delivery are not included. There are 5 components in a preterm birth phenotype: (1) maternal conditions that are present before presentation for delivery, (2) fetal conditions that are present before presentation for delivery, (3) placental pathologic conditions, (4) signs of the initiation of parturition, and (5) the pathway to delivery. This system does not force any preterm birth into a predefined phenotype and allows all relevant conditions to become part of the phenotype. Needed data can be collected from the medical records to classify every preterm birth. The classification system will improve understanding of the cause and improve surveillance across populations.

Agricultural-related chemical exposures, season of conception, and risk of gastroschisis in Washington State.

OBJECTIVE: We sought to determine if periconceptional exposure to agrichemicals was associated with the development of gastroschisis. STUDY DESIGN: We conducted a retrospective, case-controlled study using Washington State Birth Certificate and US Geological Survey databases. Cases included all live-born singleton infants with gastroschisis. Distance between a woman's residence and site of elevated exposure to agrichemicals was calculated. Multivariate regression was used to estimate the association between surface water concentrations of agrichemicals and the risk of gastroschisis. RESULTS: Eight hundred five cases and 3616 control subjects were identified. Gastroschisis occurred more frequently among those who resided <25 km from a site of high atrazine concentration (odds ratio, 1.6). Risk was related inversely to the distance between the maternal residence and the closest toxic atrazine site. In multivariate analysis, nulliparity, tobacco use, and spring conception remained significant predictive factors for gastroschisis. CONCLUSION: Maternal exposure to surface water atrazine is associated with fetal gastroschisis, particularly in spring conceptions.

Randomized comparison of intravenous terbutaline vs nitroglycerin for acute intrapartum fetal resuscitation.

OBJECTIVE: The purpose of this study was to compare terbutaline and nitroglycerin for acute intrapartum fetal resuscitation. STUDY DESIGN: Women between 32-, 42 weeks' gestation were assigned randomly to 250 microg of terbutaline or 400 microg nitroglycerin intravenously for nonreassuring fetal heart rate tracings in labor. The rate of successful acute intrapartum fetal resuscitation and the maternal hemodynamic changes were compared. Assuming a 50% failure rate in the terbutaline arm, we calculated that a total of 110 patients would be required to detect a 50% reduction in failure in the nitroglycerin group (50% to 25%), with an alpha value of .05, a beta value of .20, and a power of 80%. RESULTS: One hundred ten women had nonreassuring fetal heart rate tracings in labor; 57 women received terbutaline, and 53 women received nitroglycerin. Successful acute resuscitation rates were similar (terbutaline 71.9% and nitroglycerin 64.2%; P = .38). Terbutaline resulted in lower median contraction frequency per 10 minutes (2.9 [25-75 percentile, 1.7- 3.3] vs 4 [25-75 percentile, 2.5- 5]; P < .002) and reduced tachysystole (1.8% vs 18.9%; P = .003). Maternal mean arterial pressures decreased with nitroglycerin (81-76 mm Hg; P = .02), but not terbutaline (82-81 mm Hg; P = .73). CONCLUSION: Although terbutaline provided more effective tocolysis with less impact on maternal blood pressure, no difference was noted between nitroglycerin and terbutaline in successful acute intrapartum fetal resuscitation.