Thomas D. Shipp

The Genetic Sonogram A Method of Risk Assessment for Down Syndrome in the Second Trimester

Objective. To determine the risk of Down syndrome in fetuses with sonographic markers using the Bayes theorem and likelihood ratios. Methods. We prospectively evaluated the midtrimester sonographic features of fetuses with Down syndrome and compared them with euploid fetuses. Patients were referred for an increased risk of aneuploidy and evaluated for the presence of structural defects, a nuchal fold, short long bones, pyelectasis, an echogenic intracardiac focus, and hyperechoic bowel. All fetuses underwent amniocentesis at the time of sonographic assessment. The sensitivity, specificity, and likelihood ratios for markers were calculated both as nonisolated and isolated findings. Results. There were 164 fetuses with Down syndrome and 656 euploid fetuses. The presence of any marker resulted in sensitivity for the detection of Down syndrome of 80.5% with a false‐positive rate of 12.4%. The absence of any markers conferred a likelihood ratio of 0.2, decreasing the risk of Down syndrome by 80%. As an isolated marker, the nuchal fold had an “infinite” likelihood ratio for Down syndrome; a short humerus had a likelihood ratio of 5.8, whereas structural anomalies had a likelihood ratio of 3.3. Other isolated markers had low likelihood ratios because of the higher prevalence in the unaffected population. The likelihood ratios for the presence of 1, 2, and 3 of any of the markers were 1.9, 6.2, and 80, respectively. Conclusions. Although an isolated marker with a low likelihood ratio may not increase a patients risk of Down syndrome, the presence of such a marker precludes reducing the risk of aneuploidy. Clusters of markers appear to confer a higher risk.

Rate of uterine rupture during a trial of labor in women with one or two prior cesarean deliveries

OBJECTIVE We sought to determine whether there is a difference in the rate of symptomatic uterine rupture after a trial of labor in women who have had 1 versus 2 prior cesarean deliveries. STUDY DESIGN The medical records of all women with a history of either 1 or 2 prior cesarean deliveries who elected to undergo a trial of labor during a 12-year period (July 1984-June 1996) at the Brigham and Womens Hospital were reviewed. Rates of uterine rupture were compared for these 2 groups. Potential confounding variables were controlled by using logistic regression analyses. RESULTS Women with 1 prior cesarean delivery (n = 3757) had a rate of uterine rupture of 0.8%, whereas women with 2 prior cesarean deliveries (n = 134) had a rate of uterine rupture of 3.7% (P =.001). In a logistic regression analysis that was controlled for maternal age, use of epidural analgesia, oxytocin induction, oxytocin augmentation, the use of prostaglandin E(2) gel, birth weight, gestational age, type of prior hysterotomy, year of trial of labor, and prior vaginal delivery, the odds ratio for uterine rupture in those patients with 2 prior cesarean deliveries was 4.8 (95% confidence interval, 1.8-13. 2) CONCLUSIONS Women with a history of 2 prior cesarean deliveries have an almost 5-fold greater risk of uterine rupture than those with only 1 prior cesarean delivery.

Interdelivery interval and risk of symptomatic uterine rupture

Objective To relate interdelivery interval to risk of uterine rupture during a trial of labor after prior cesarean delivery. Methods We reviewed the medical records of all women who had a trial of labor after cesarean delivery over 12 years (July 1984 to June 1996). Analysis was limited to women with only one prior cesarean delivery and no prior vaginal deliveries who delivered term singletons and whose medical records included the month and year of the prior delivery. The time in months between the prior cesarean delivery and the index trial of labor was calculated, and the women were divided accordingly to permit comparison with respect to symptomatic uterine rupture. Results Two thousand four hundred nine women had trials of labor after one prior cesarean delivery and had complete data from the medical records. There were 29 uterine ruptures (1.2%) in the population. For interdelivery intervals up to 18 months, the uterine rupture rate was 2.25% (seven of 311) compared with 1.05% (22 of 2098) with intervals of 19 months or longer (P = .07). Multiple logistic regression was used to assess the risk of uterine rupture according to interdelivery interval while controlling for maternal age, public assistance, length of labor, gestational age at least 41 weeks, and oxytocin use. Women with interdelivery intervals of up to 18 months were three times as likely (95% confidence interval, 1.2, 7.2) to have symptomatic uterine rupture. Conclusion Interdelivery intervals of up to 18 months were associated with increased risk of symptomatic uterine rupture during a trial of labor after cesarean delivery compared with that for longer interdelivery intervals.

The sonographic diagnosis of Dandy-Walker and Dandy-Walker variant: associated findings and outcomes.

Outcomes of pregnancies with sonographically diagnosed Dandy–Walker (DW) or Dandy–Walker variant (DWV) syndromes vary widely. We examined our own experience with these diagnoses in an effort to identify those sonographic features that best predicted neonatal outcome. We identified 50 fetuses with DW and 49 with DWV diagnosed sonographically. Eighty‐six per cent of fetuses with DW and 85% of fetuses with DWV had other sonographically identifiable anomalies, the most common being ventriculomegaly (DW: 32%; DWV: 27%) and cardiac defects (DW:38%; DWV: 41%). Forty‐six per cent and 36% of available karyotypes in cases of DW and DWV, respectively, were abnormal. 50 out of 99 women in our series elected pregnancy termination. Only three pregnancies with DW resulted in a living infant, and only one of these had a normal paediatric examination at six‐week follow‐up. Thirteen out of 49 infants with DWV survived the neonatal period and 7 of 13 were reported initially as normal infants, including six with an isolated finding of DWV. We conclude that overall, the prognosis for these posterior fossa defects is grim but not uniformly fatal. The presence of other anomalies is associated with the worst prognosis. Isolated Dandy–Walker variant has the highest chance of leading to a normal neonate. Copyright

Significance of an Echogenic Intracardiac Focus in Fetuses at High and Low Risk for Aneuploidy

Our objective was to evaluate the significance of an echogenic intracardiac focus in a mixed population of fetuses at high and low risk for aneuploidy. Over a 1 year period, we prospectively identified all fetuses with an echogenic intracardiac focus seen during prenatal sonography. A detailed structural evaluation was performed on each fetus as permitted by gestational age. The location and number of foci were tabulated prospectively, as were associated abnormalities. Follow‐up was obtained by review of the medical record. Of the 290 fetuses who had an echogenic intracardiac focus, 14 of them were aneuploid (4.8%). Of the 290 mothers, 125 women were aged 35 years or older and 165 women were younger than 35 years old. Among the 125 fetuses born to women 35 years or older, eight were aneuploid fetuses (6.4%), while among the 165 fetuses of younger mothers, six were aneuploid fetuses (3.6%) (rate ratio = 1.8; 95% confidence interval [extremes] = 0.6, 4.9). Only one of the 14 aneuploid fetuses had an echogenic intracardiac focus as the only sonographic finding, and this occurred in a woman aged 41 years. The majority of the echogenic intracardiac foci (87.6%) were located in the left ventricle, while 4.8% of the foci were right‐sided and 7.6% were bilateral. Among the 14 aneuploid fetuses, 14% had bilateral echogenic intracardiac foci and 7% had right‐sided foci. Among the euploid fetuses, 7.3% had bilateral echogenic intracardiac foci and 4.7% had right‐sided foci. In conclusion, we have shown that the presence of an echogenic intracardiac focus does raise the risk that the fetus has a chromosomal abnormality, most commonly Down syndrome, although all but one aneuploid fetus in our study had other sonographic findings.

What does magnetic resonance imaging add to the prenatal sonographic diagnosis of ventriculomegaly

The purpose of this study was to determine the contribution of magnetic resonance imaging (MRI) in evaluating fetuses with the sonographic diagnosis of ventriculomegaly (VM).

How Sonographic Tomography Will Change the Face of Obstetric Sonography A Pilot Study

This study was undertaken to determine whether 3‐dimensional (3D) volume sonography (sonographic tomography) can yield a far quicker and equally accurate anatomic examination of the second‐trimester fetus compared with traditional 2‐dimensional (2D) scanning.

Intrapartum Uterine Rupture and Dehiscence in Patients With Prior Lower Uterine Segment Vertical and Transverse Incisions

OBJECTIVE To determine whether gravidas with prior low vertical uterine incision(s) are at a higher risk for uterine rupture during a trial of labor after cesarean delivery than women with prior low transverse uterine incision(s). METHODS The medical records of women undergoing a trial of labor after prior cesarean delivery over a 12-year period (July 1984-June 1996) at a tertiary-care hospital were reviewed. Maternal and perinatal outcomes for women with prior low transverse and low vertical incision were compared. Women whose low vertical incision was noted to extend into the corpus of the uterus were excluded. All uterine scar disruptions, which included both symptomatic ruptures and detected asymptomatic dehiscences, were analyzed together, and ruptures were examined separately. RESULTS The outcomes of 2912 patients undergoing trial of labor for the low transverse group and 377 patients undergoing trial of labor for the low vertical group were compared. Overall, there were 38 (1.3%) scar disruptions in the low transverse group and six (1.6%) in the low vertical group, P = .6. There were 28 (1.0%) symptomatic ruptures in the low transverse group and 3 (0.8%) in the low vertical group, P > .999. The study had a power of 80% to detect an increase in the low vertical rupture rate from 1% (as noted for low transverse incisions) to 3%. CONCLUSION Gravidas with a prior low vertical uterine incision are not at increased risk for uterine rupture during a trial of labor compared with women with a prior low transverse uterine incision.

Trial of labor after cesarean delivery : The effect of previous vaginal delivery

OBJECTIVE This study examined the effects of order of previous modes of delivery on the rate of cesarean delivery and duration of a trial of labor among women with a history of 1 previous cesarean delivery and 1 previous vaginal delivery. STUDY DESIGN The medical records of 4393 women at our institution who were seen June 1984-July 1996 for a trial of labor after a previous cesarean delivery were abstracted. The 800 women with a history of 1 previous cesarean and 1 previous vaginal delivery were included in this analysis. They were split into 2 groups by obstetric history: (1) 1 cesarean delivery followed by 1 vaginal delivery (vaginal last) and (2) 1 vaginal delivery followed by 1 cesarean delivery (cesarean last). Patient characteristics, durations of labor, and rates of cesarean delivery were compared with chi2 analysis, the Student t test, and the Wilcoxon rank sum test. Possible confounding variables were controlled for with multivariate logistic regression. RESULTS The rates of cesarean delivery for the vaginal last and cesarean last groups were 7.2% and 14.7%, respectively (P = .002). The median durations of labor for the vaginal last and cesarean last groups were 5.6 and 7.0 hours, respectively (P = .01). The differences in cesarean rates and durations of labor were seen regardless of the indication for the previous cesarean delivery. CONCLUSIONS Among women with 1 previous cesarean and 1 previous vaginal delivery, those whose most recent delivery was vaginal had a lower rate of cesarean delivery and shorter duration of labor than did those whose most recent delivery was cesarean.

Three-dimensional ultrasound detection of abnormally located intrauterine contraceptive devices which are a source of pelvic pain and abnormal bleeding.

To determine whether intrauterine contraceptive devices (IUDs) that are located abnormally within the myometrium or cervix cause a higher incidence of pelvic pain and abnormal bleeding compared with normally positioned devices.