David A McLean

The natural history of a positive response to transfundal pressure in women at risk for cervical incompetence

OBJECTIVE Our purpose was to observe the evolution of the endocervical canal length in women at risk for cervical incompetence after a positive response to transfundal pressure. STUDY DESIGN Ten women at risk for cervical incompetence had a midtrimester cervical evaluation with transvaginal ultrasonography and transfundal pressure. With a transvaginal probe, the endocervical canal length was first measured. Transfundal pressure was then applied and the endocervical canal length was remeasured. All patients had a positive response to transfundal pressure as defined by a decrease in endocervical canal length after application of transfundal pressure. At the initial evaluation the digital examination of the cervix had revealed a closed and long cervix in all 10 cases. In 9 of the 10 patients repeat examinations were performed until the endocervical canal length progressively shortened to <10 mm or the digital examination revealed a dilated cervix. The endocervical canal lengths after application of transfundal pressure from the first and last examination were compared. One patient was lost to follow-up, but the obstetric outcome was available. RESULTS The median time interval between the first and final examination was 7 (2 to 20) days in 9 of the patients. The median (range) gestational age at the first and final examination was 19.0 (15 to 22) weeks (n = 10) and 20.5 (18 to 24) weeks (n = 9), respectively. There was significant shortening of the endocervical canal length from the first to the last examination; 12.2 (4 to 20) mm (n = 10) versus 0.0 (0 to 9.5) mm (n = 9), p = 0.008. Six patients had membranes at the external cervical os before application of transfundal pressure at the last examination. The one patient lost to ultrasonographic follow-up had a pregnancy loss at 23 weeks of gestation, 6 weeks after a positive response to transfundal pressure. CONCLUSION In patients at risk for cervical incompetence, shortening of the endocervical canal length in response to transfundal pressure requires treatment with a cervical cerclage because it is associated with progressive cervical changes over 1 to 3 weeks.

Second-Trimester Ultrasound Markers for Detection of Trisomy 21: Which Markers Are Best?

Objective To investigate which second-trimester ultrasound markers for aneuploidy are the most diagnostically efficient in detecting fetal trisomy 21. Methods All second-trimester genetic sonograms performed since November 1, 1992 for women at increased risk for fetal trisomy 21 were analyzed restrospectively. Statistical analysis included descriptive statistics, the test of proportions, and univariate and multivariable logistic regression analysis using trisomy 21 as the dependent variable and ten aneuploidy ultrasound markers as independent variables. Results There were 581 normal fetuses, 23 with trisomy 21 and four with other chromosomal abnormalities. When one or more abnormal ultrasound markers were present, the sensitivity and flase-positive rate for trisomy 21 were 87% and 13.4%, respectively. After adjusting for confounders, multivariate logistic regression analysis showed the best combination of ultrasound markers for detecting trisomy 21 to be nuchal fold thickening (relative risk [RR] 85.5; 95% CONFIDENCE INTERVAL [CI] 20.4; 95% CI 4.5, 92.1)). The model combining these three ultrasound markers yielded a sensitivity of 87% and a false-positive rate of 6.7%. Conclusion By using only three ultrasound markers (combination of nuchal fold thickening, pyelectasis, and short humerus) the false-positive rate is decreased from 13.4% to 6.7% without any compromise in the sensitivity (87%). The clinical usefulness of evaluating the various secondtrimester ultrasound markers needs to be evaluated in prospective studies.

Choice of second-trimester genetic sonogram for detection of trisomy 21

Objective To determine the utilization rate of second-trimester genetic sonogram and its role in influencing the decision for amniocentesis in women at increased risk for fetal trisomy 21. Methods From November 1, 1993, to December 31, 1996, a second-trimester genetic sonogram or only genetic amniocentesis (as a first choice) were offered to pregnant women referred to our institution who were at increased risk for fetal trisomy 21. Results During the study period, 2089 women were referred to our unit for genetic prenatal diagnosis; of these, 1426 (68%) chose only genetic amniocentesis, and 663 (32%) chose a genetic sonogram as their first option. The yearly utilization rates of genetic sonogram were two of 477 or 0.4% for 1993, 82 of 495 or 16.6% for 1994, 251 of 523 or 48.0% for 1995, and 328 of 594 or 55.2% for 1996. Adjusting for potential confounders, multivariable logistic regression analysis showed that the most important factors associated with the womens decision to undergo genetic amniocentesis were three or more ultrasound markers present (relative risk [RR] 189.5, 95% confidence interval [CI] 37.1, 980.0), two ultrasound markers present (RR 47.2, 95% CI 9.8, 267.8), one ultrasound marker present (RR 12.7, 95% CI 5.5, 29.7), and abnormal serum biochemistry (RR 3.0, 95% CI 1.0, 8.9). Conclusion The increasing utilization trend, in conjunction with the fact that an abnormal sonogram was the most influential factor in womens decision to undergo genetic amniocentesis, suggests that genetic sonogram services for detection of trisomy 21 should be added to the armamentarium of all prenatal diagnostic centers.

Incarceration of the Gravid Uterus

Retroversion of the first trimester uterus occurs in 6 to 19 per cent of all pregnancies and usually does not cause problems. If the uterus remains retroverted as the pregnancy advances, it may become wedged into the pelvic cavity. This complication is referred to as uterine incarceration which can lead to spontaneous abortion, preterm labor, uterine dystocia, and inadvertent incision into the cervix or the bladder during cesarean section in cases of unrecognized incarceration. Seven cases of uterine incarceration are presented with a detailed review including clinical signs and symptoms, physical findings, ultrasound findings, and treatment modalities for each stage of pregnancy. Moreover, we present a new method of treatment for second trimester uterine incarceration.

Foot Length in Fetuses with Abnormal Growth

Sonographic fetal foot length is highly predictive of gestational age. In order to assess the reliability of this parameter in predicting gestational age in cases of abnormal fetal growth, we examined fetal foot length in small‐ and large‐for‐gestational‐age fetuses. A nomogram of foot length versus gestational age between 15 and 37 weeks was constructed using cross‐sectional data obtained from 5372 singleton fetuses. Fetal foot lengths for small‐for‐gestational‐age fetuses (estimated fetal weight below the 10th percentile) and large‐for‐gestational‐age fetuses (above the >90th percentile) fetuses were plotted against the foot length nomogram in order to determine the number of small‐for‐gestational‐age fetuses and large‐for‐gestational‐age fetuses with foot lengths below the 10th and above the 90th percentiles, respectively. Of the 586 small‐for‐gestational‐age fetuses, 355 (60.6%) had foot lengths below the 10th percentile on the nomogram. When foot lengths from large‐for‐gestational‐age fetuses were plotted on the foot length nomogram, 29.4% (219 of 744) had measurements above the 90th percentile. Fetal foot length can be influenced by growth restriction as well as states of accelerated fetal growth. Our findings imply that there are limitations to the use of fetal foot length for gestational age assessment, particularly in fetuses with growth abnormalities.

Fetal intracardiac echogenic foci: visualization depends on the orientation of the 4-chamber view.

To compare the frequency of visualization of echogenic intracardiac foci in different cardiac views.

Arteriovenous Cord Blood pH Discordancy in a High-Risk Population and Its Clinical Significance

Five hundred and twenty patients with gestational ages between 24 and 42 weeks who had both umbilical cord venous (V) and arterial (A) gases recorded were studied retrospectively to 1) establish th...

Blepharophimosis, hypoplastic radius, hypoplastic left heart, telecanthus, hydronephrosis, fused metacarpals, and “prehensile” halluces: A new syndrome?

We report on the prenatal ultrasound and postnatal findings in an infant born to a healthy, nonconsanguineous couple. The infant had microcephaly, telecanthus, blepharophimosis, cleft palate, micrognathia, abnormally modeled ears, hypoplastic left heart, hypoplastic radii and ulnae with radial subluxation, pseudoarthrotic distal humeri, fused metacarpals, tibial bowing, unusual feet with long halluces, hydronephrosis, patent urachus, abnormal electroencephalogram, and normal karyotype. To our knowledge, this combination of anomalies has not been recognized previously and may represent a new condition.