Faculty Bibliography

The most significant anatomical structure of the umbilical cord is its level of coiling. The coiled geometry of the umbilical cord largely affects umbilical blood flow that is vital for fetus's well-being and normal development. In this study, we developed a computational model of steady blood flow through the coiled structure of an umbilical artery. The results showed that the driving pressure for a given blood flow rate is increasing as the number of coils in cord structure increases. The driving gradient pressures also vary with the pitch that dictates the coils' spreading. The coiled structure is resulting in interwoven streamlines along the helix and wall shear stresses (WSS) with significant spatial gradients along the cross-sectional perimeter anywhere within the helical coil. These gradients may have an adverse effect on the development of the fetus cardiovascular system in cases with over coiling (OC) or under coiling (UC) characteristics. The number of coils does not affect the distribution and levels of WSS. However, when the coils are more spread (eg, larger pitch number), the maximal WSS is significantly smaller. Cases with twisted and OC cords seem to yield very large values and gradients of WSS, which may place the fetus into high risk of abnormal development

OBJECTIVE: The aim of this study was to evaluate a rapid 3-dimensional ultrasound-assisted technique for evaluation of the corpus callosum as an integral part of the anatomic survey. STUDY DESIGN: Transabdominal 3-dimensioal gray scale and power Doppler volumes of the fetal brain were acquired in 102 consecutive healthy fetuses at 20-23 postmenstrual weeks. Offline analysis was performed by 2 of the authors using a systematic approach of 'volume manipulation.' Diagnostic-quality visualization of the corpus callosum and the pericallosal arteries on the median plane was recorded by the 2 examiners independently. RESULTS: The median plane was easily obtained in all cases. Diagnostic-quality images of the corpus callosum were recorded in 93.1% and 99.0% and of the pericallosal arteries in 94.4% and 95.5% of the cases, by the 2 examiners, respectively. CONCLUSION: Three-dimensional ultrasound enables a rapid and easy evaluation of the corpus callosum that may facilitate its inclusion as an integral part of the routine anatomic survey

With the increased use and quality of ultrasound in pregnancy, adenxal masses are being encountered with greater frequency. Fortunately, most of such masses are benign and resolve on their own. However, complications such as ovarian torsion can occur. In addition, a malignancy can be present in a small minority of cases. In this article, we review the available literature on this subject to help guide the clinician in the diagnosis and management of adnexal masses in pregnancy.

OBJECTIVE: To estimate the effectiveness of second-trimester genetic sonography in modifying Down syndrome screening test results. METHODS: The First and Second Trimester Evaluation of Risk (FASTER) aneuploidy screening trial participants were studied from 13 centers where a 15- to 23-week genetic sonogram was performed in the same center. Midtrimester Down syndrome risks were estimated for five screening test policies: first-trimester combined, second-trimester quadruple, and testing sequentially by integrated, stepwise, or contingent protocols. The maternal age-specific risk and the screening test risk were modified using likelihood ratios derived from the ultrasound findings. Separate likelihood ratios were obtained for the presence or absence of at least one major fetal structural malformation and for each 'soft' sonographic marker statistically significant at the P<.005 level. Detection and false-positive rate were calculated for the genetic sonogram alone and for each test before and after risk modification. RESULTS: A total of 7,842 pregnancies were studied, including 59 with Down syndrome. Major malformations and 8 of the 18 soft markers evaluated were highly significant. The detection rate for a 5% false-positive rate for the genetic sonogram alone was 69%; the detection rate increased from 81% to 90% with the combined test, from 81% to 90% with the quadruple test, from 93% to 98% with the integrated test, from 97% to 98% with the stepwise test, and from 95% to 97% with the contingent test. The stepwise and contingent use of the genetic sonogram after first-trimester screening both yielded a 90% detection rate. CONCLUSION: Genetic sonography can increase detection rates substantially for combined and quadruple tests and more modestly for sequential protocols. Substituting sonography for quadruple markers in sequential screening was not useful. LEVEL OF EVIDENCE: II

A number of studies have reported an association between low concentrations of serum folate and preterm birth. Folate supplementation during pregnancy increased the length of pregnancy in some but not all clinical trials. This cohort study investigated whether preconceptional folate supplementation (as ascertained by patient questionnaire in the first trimester of pregnancy) lowers the risk of spontaneous preterm birth. The investigators analyzed data collected from a cohort of 34,480 low-risk singleton pregnancies in women enrolled in a previous prospective cohort study on Down syndrome screening conducted at 15 US centers between 1999 and 2002. Duration of pregnancy was estimated by ultrasound measurement in the first trimester. Spontaneous preterm birth was defined as preterm birth between 20 and 37 weeks with no medical or obstetrical complications that constituted indications for delivery. The effects of the duration of preconceptional folate supplementation of <= 1 year (long-term), <1 year and the effect of no supplementation on risk of spontaneous preterm birth were compared using time-to-event analysis. Data were subjected to analysis with multivariable logistic regression. Compared to women who did not take a folate supplement, the risk of spontaneous preterm delivery between 20 and 28 weeks was 70% lower in women who took folate supplements for a year or longer before pregnancy (0.27% vs 0.04%); the hazard ratio was 0.22, with a 95% confidence interval of 0.08 to 0.61, P = 0.004. Long-term folate supplementation reduced the risk between 28 and 32 weeks by over 50% (0.38% vs 0.18%) (hazard ratio, 0.45; 95% confidence interval, 0.24-0.83, P = 0.010). Supplementation had no significant effect on the risk of spontaneous preterm birth beyond 32 weeks. Adjustment for maternal variables (age, body mass index, race and ethnicity, educational level, marital status, smoking, parity and history of prior preterm birth) did not affect the association between long-term folate and risk of spontaneous preterm birth but did eliminate the association found in unadjusted analysis between duration of preconceptional folate supplementation less than one year and risk. These findings suggest that preconceptional folate supplementation for a year or longer may substantially reduce the risk of early spontaneous preterm birth. The risk is lower with longer duration of folate supplementation before pregnancy. The beneficial effect of folic acid does not appear to be associated with other complications of pregnancy such as preeclampsia, small for gestational age infant, placental abruption, or nonspontaneous preterm birth

OBJECTIVE: The purpose of this study was to assess the vascular indices generated by 3-dimensional (3D) power Doppler angiography by evaluating the cyclic changes in the vascularity of normal ovaries, including those that were ovulating, nonovulating, and hormonally suppressed. METHODS: In this prospective longitudinal observational study, a cohort of premenopausal regularly menstruating women with no known ovarian disease underwent 3D power Doppler imaging every 2 to 3 days for the duration of 1 menstrual cycle. Four indices were generated: vascularization index (VI), flow index (FI), vascularization-flow index (VFI), and mean grayness. Comparisons of vascularity were made between ovulating, nonovulating, and hormonally suppressed ovaries. Normal ranges were established and graphed longitudinally. RESULTS: Eighteen participants (36 ovaries) ages 28 to 45 years underwent an average of 10 examinations, yielding 368 acquired ovarian volumes for analysis. Seven participants used hormonal contraception. The VI, FI, and VFI were closely correlated (Pearson product moment correlation coefficients, 0.52-0.95). The vascular indices of ovulating ovaries were significantly higher than those of nonovulating ovaries (VI, FI, and VFI, all P < .001), with the largest discrepancies during the luteal phase. Hormonally suppressed ovaries had significantly lower vascularity throughout the cycle (VI, P < .002; FI, P < .001; VFI, P < .007). The vascular indices of all groups appeared to drop during the late follicular period and then rise again. CONCLUSIONS: The VI would suffice as the principal vascular parameter for 3D power Doppler analysis. Preovulatory scans may be more useful for distinguishing pathologic vascularization. Hormonally suppressed ovaries have significantly lower vascularity throughout the cycle. Normal-appearing ovaries with vascular indices above the normal ranges established by these data may warrant further investigation