Z. Weinraub

Dynamic ultrasonographic imaging of the third stage of labor: New perspectives into third-stage mechanisms

OBJECTIVE Dynamic ultrasonographic imaging of the third stage of labor was performed to document ultrasonographic findings and to present new perspectives into third-stage mechanisms. STUDY DESIGN Twenty-five normal deliveries and five with prolonged third-stage labor were studied. RESULTS Normal third-stage labor could be divided into four phases: (1) latent phase, characterized by thick, placenta-free wall and thin, placenta-site wall; (2) contraction phase, with thickening of placenta-site wall (from < 1 cm to > 2 cm); (3) detachment phase, in which the placenta completes its separation and detaches; and (4) expulsion phase, with a sliding movement of the placenta. Although oxytocic agents were routinely used, they do not seem to influence the findings. In five cases with retained placenta the placenta-site wall was initially thin. In four of them it became thick, and the placenta was removed by traction of the cord, whereas in the fifth case the placenta-site wall remained thin and the placenta had to be removed manually. CONCLUSION Shearing forces seem to tear the decidual septae and thereby separate the placenta. This process is completed only when the placenta-site wall attains full thickness. In cases of prolonged third-stage labor, traction of the cord should be applied only when this phase is completed and the actual sliding movement of the placenta is observed.

Comparison of nuchal translucency measurement and second-trimester triple serum screening in twin versus singleton pregnancies

Maternal serum screening for Down syndrome (DS) in twin pregnancies poses difficulties due to a lack of precise biochemical information about each co‐twin. The current study attempts, for the first time, to compare two screening methods: nuchal translucency (NT) measurement and serum screening for DS, in twin pregnancies. 60 women with twin pregnancies (study group) underwent both first‐trimester NT scanning and mid‐trimester triple‐marker serum screening, and were followed throughout their gestation. Nuchal translucency measurements were compared with a matched control of 120 singleton pregnancies with a similar (±2 years) maternal age and fetal crown–rump length (CRL) (±3 mm). In both analyses, a risk of 1:380, or higher, of having a DS newborn was considered screen positive. Both mean maternal age (31±3 years) and CRL (62±11 mm) were similar in the study and control groups. The median NT measurement expressed as multiples of the median (MOM) for CRL was similar in the study and control groups (0.85 and 0.88, respectively). Based on NT measurements, 5 per cent of the pregnancies in the study group and 2.5 per cent in the control group were defined as screen positive (p =N · S). Mid‐gestation serum screening was associated with 15 per cent and 6 per cent screen‐positive rate in study and control groups, respectively (p<0.05). There was a ratio of 1:3 screen‐positive rate between first and second‐trimester screening tests within the study group. This high false‐positive rate results led to 18.3 per cent amniocentesis rate in the study group compared with 7.5 per cent of the control group (p<0.03). Only one co‐twin which was picked up by the NT screen was further diagnosed as trisomy 21, and one co‐twin with cardiac and neural tube defect was missed by the two screening tests and was later picked up in an anomaly scan. Although the current series is too small to provoke any changes in screening practice, when twin pregnancies are diagnosed, it seems very reasonable to offer them NT measurement. A larger group may be needed to clarify which approach is the most beneficial screening policy for this highly selected group of pregnant women. Copyright

Changes in amniotic fluid lecithin-sphingomyelin ratio following maternal dexamethasone administration.

The effect of dexamethasone on amniotic fluid lecithin-sphingomyelin (L/S) ratio was measured in 15 fetuses of 34 weeks or less of gestation. Six of the patients presented with premature rupture of the membranes. A rise in the L/S ratio is mature levels (two or more) was observed 24 hours to 11 days after the start of treatment in 12 patients. In 2 patients (one second twin and one anencephalic fetus), no rise in L/S ratio occurred. Of 12 cases whch ended in premature delivery (29 to 35 weeks) only one infant, a second twin delivered at the thirtieth week with a posttreatment L/S ration o1.4 weighing 1,240 grams, developed severe respiratory distress syndrome and died. Tt is suggested that dexamethasome accelerates fetal lung maturation by increasing surfactant synthesis or release, and this may be achieved as early as the twenty-eighth week of pregnancy.

Triplet, quadruplet and quintuplet pregnancies: Management and outcome

The management and outcome of 46 pregnancies, 37 triplets, 7 quadruplets and 2 quintuplets, were analysed. Management of pregnancies, initiated upon diagnosis of multiple pregnancy, included bed rest, β‐mimetic agents, dexamethasone late in the second trimester and selective cerclage. The mean gestational age at labor was 235 days in triplet pregnancies, 241 for quadruplets and 220 days for quintuplets. Fifty‐four percent of the deliveries were by cesarean section and the remainder per vaginam. The mean weight of the neonates was 1809 g for the triplets, 1837 g for quadruplets and 1284 g for the quintuplets. The mean overall Apgar score was 8.13, total perinatal mortality 14.8% and 9.4% in cases more than 28 weeks. There was no statistically significant difference in the outcome for triplets born vaginally or by cesarean section. In recent years there has been a pronounced reduction in neonatal mortality, dropping from 17.3% during 1970–78 to 5.9% from 1979 to 1983 (p<0.05), probably due to the improved neonatal treatment.

Correlation between nuchal translucency and nuchal skin‐fold measurements in Down syndrome and unaffected fetuses

To assess whether there is a correlation between nuchal translucency (NT) and nuchal skin‐fold (NF) measurements, in Down syndrome and in normal pregnancies.

Utilization of the nuchal translucency image-scoring method during training of new examiners.

Training of new examiners, utilizing 1st-trimester nuchal translucency ultrasound screening, is mandatory for obtaining reproducible measurements. This study examined the contribution of the nuchal translucency image-scoring method to the process of training and its utilization as an objective tool of image evaluation and a tool for approving qualification. The study included an evaluation of the performance of two new examiners (examiners A and B) before and after intervention, using the image-scoring method. The preintervention period included 75 images evaluated by two reviewers using general evaluation and the scoring method. The report of the scoring method was submitted to the examiners and was applied to 55 images performed afterwards. The agreement between two reviewers in classifying the first 75 images as ‘accepted’ or ‘rejected’ was tested using general evaluation versus the scoring method. The effect of the intervention was examined by comparing the quality of the images between the two time periods. A chart indicating final scores of 80 successive images analyzed by examiner A was used to set criteria for assessing qualification. Using general evaluation, the reviewers disagreed on 19 (25%) of the images, whereas using the scoring method they disagreed on only 5 (7%, p < 0.01). Comparison before and after application of the intervention demonstrated significant improvement expressed by the increased rate of better quality groups (p < 0.001) and improved mean scores from 4.31 ± 0.31 to 6.15 ± 0.32 (p < 0.001). Enhanced improvement of examiner’s A performance could be attributed to the intervention rather than to his learning curve. Improvement was demonstrated in all the criteria examined; however, it was significant only for images size (from 33 to 98%), amnion demonstration (from 13 to 42%), and caliper placement (from 49 to 71%). Examiner’s A chart enabled us to set standards for assessing competence, based on the scoring method. These included a minimum of 40 scans, followed by more than ten sequential images of acceptable quality. The scoring method contributed to the process of training, as it made possible to objectively evaluate the images, pointed out specific erros, served as an efficient tool of intervention, and might be used for ascertaining competence. We recommend to consider its utilization in centers running 1st-trimester ultrasound screening during training new examiners.

Antenatal sonographic findings of right pulmonary agenesis with ipsilateral microtia: a possible new laterality association

Right pulmonary agenesis is a rare congenital malformation which results in secondary dextrocardia in situs solitus. Ipsilateral microtia in this context composes a laterality syndrome. The prenatal sonographic findings of this abnormality have not been previously reported. We describe the association of dextrocardia in situs solitus, intact diaphragm and right microtia. This was sonographically diagnosed at mid‐gestation in an euploid fetus. Surgical evacuation of the pregnancy confirmed the external malformation. Laterality association should be assessed in a fetus with sonographic findings of pulmonary agenesis. The differential diagnosis and updated literature review is presented. Copyright

Bedside estimation of Down syndrome risk from second‐trimester ultrasound prenasal thickness

To construct tables for ‘bedside’ estimation of Down syndrome risk based on maternal age and ultrasound prenasal thickness (PT) measurements.

On-to-on versus on-to-out nuchal translucency measurements

Objective To analyze variables affecting the differences between on‐to‐on and on‐to‐out methods of nuchal translucency measurement.

Combined first trimester nuchal translucency and second trimester biochemical screening tests among normal pregnancies

We prospectively examined whether first trimester nuchal translucency (NT) and second trimester triple test (TT) results are correlated, and determined overlapping and mutual screen‐positive rates. Results of NT, TT, amniocentesis and pregnancy outcome were obtained in 508 normal pregnancies. Inter‐test correlation was performed by comparing the likelihood ratios (LR). Overlapping of screen‐positive cases, of NT and TT, was determined by comparing mutual risks for Down syndrome (DS) livebirth of ≥1:380. Combined screen‐positive rates were evaluated by using summation risk (NT and/or TT exhibiting a risk ≥1:380) and calculated risk (new risk ≥1:380, based on multiplication of LRNT and LRTT). Screen‐positive rates between NT and TT differed significantly and when either test showed an increased risk for DS, the probability of the other to predict the same was negligible (p<0.001). Overall screen‐positive rates, at a risk ≥1:380, were 2% and 5.7% for NT and TT, respectively. Summation and calculated combining methods were associated with 7.5% and 2.0% screen‐positive rates, respectively. Amniocentesis was performed on 20.7% of the cases, mostly screen‐negative ones. Our results showed that, in normal pregnancies, NT and TT do not correlate and that their combined calculated risk in normal pregnancies is associated with a low screen‐positive rate of 2.0%. Copyright