The application of color power angiography to the longitudinal quantification of blood flow volume in the fetal middle cerebral arteries, ascending aorta, descending aorta, and renal arteries during gestation.

OBJECTIVE: This study was undertaken to determine by means of color power angiography the longitudinal changes in the diameters and the flow volumes of 4 major fetal arteries during gestation. STUDY DESIGN: The middle cerebral artery, the ascending aorta, the descending aorta, and the renal arteries in 81 appropriate-for-gestational-age fetuses were examined longitudinally between 24 and 38 weeks' gestation by means of color power angiography. In addition to measurement of the diameters of these arteries, Doppler velocimetry was performed. Flow volume was calculated from the cross-sectional areas of the arteries and the velocity integral of the Doppler waveforms. RESULTS: The mean (+/-SD) gestational age at delivery and birth weight were 39.8 +/- 1. 6 weeks and 3326 +/- 345 g, respectively. The diameters and flow volumes of all the arteries increased significantly as gestational age advanced. Flow volume increased from 39 +/- 19.0 mL/min to 140 +/- 63.9 mL/min in the middle cerebral artery, from 216.2 +/- 77.6 to 937.4 mL/min in the ascending aorta, from 124.4 +/- 76.6 to 390.0 mL/min in the descending aorta, and from 27.5 +/- 16.8 to 80.3 +/- 57.3 mL/min in the renal arteries. When blood flow volume was adjusted to milliliters per kilogram body weight, an initial significant fall in blood flow was seen in all the vessels to a minimal level at 30 weeks' gestation; blood flow rose thereafter, although not significantly, until term. The ratios of flow volume in the ascending aorta to those in the other vessels increased with gestation, with the highest ratio being that between the ascending aorta and the renal arteries. CONCLUSION: Identification of fetal arteries with color power angiography is easy and highly sensitive. The distributions of blood flow in various fetal arteries exhibited regional differences, with significantly more blood flow to the brain. These normative baseline values may be useful in the diagnosis of congenital cardiac anomalies and also in the diagnosis and monitoring of fetuses with intrauterine growth restriction.

Spontaneous superfetation diagnosed in the first trimester with successful outcome.

We report a twin pregnancy in which a 4-week discordance in size between the fetuses was identified in the first trimester. The discordance was maintained throughout the pregnancy, which was otherwise uneventful and resulted in the delivery of a live girl and boy.

Genetic amniocentesis: gestation-specific pregnancy outcome and comparison of outcome following early and traditional amniocentesis.

Amniocentesis remains the most common prenatal diagnostic invasive procedure for fetal karyotyping. During counselling prior to this procedure miscarriage rates are often quoted as a single figure. In this review of 2924 amniocenteses, we report that miscarriage rates vary with the gestational age at which the procedure is performed. The total miscarriage rate was 1.0 per cent after early amniocenteses (11 + 0-14 + 6 weeks) and 1.2 per cent after traditional mid-trimester amniocenteses (15 + 0-18 + 6 weeks). The rate was greatest (3.1 per cent) for amniocenteses performed after 18 + 6 weeks' gestation. The cumulative miscarriage risk increased from 0.03 per cent one week after the procedure to plateau at 1.1 per cent five weeks after the procedure. The preterm and still-birth rates following amniocenteses were similar in early and traditional mid-trimester amniocenteses but were significantly higher when amniocenteses were performed after 19 weeks' gestation. Although the incidence of talipes equinovarus was higher after early amniocentesis compared with traditional mid-trimester amniocenteses (1.4 per cent versus 0.2 per cent), none of the affected infants required corrective surgery. We conclude that counselling for this procedure should be tailored to each unit's unintended fetal loss rate based on cumulative rates. Such figures should be available to parents to assist them in their decision-making.

Gastroschisis associated with bladder evisceration complicated by hydronephrosis presenting antenatally.

We report here a case of gastroschisis associated with bladder evisceration and complicated by rapidly developing hydronephrosis diagnosed antenatally. The timing of delivery was determined by the hydronephrosis, associated bowel dilatation and polyhydramnios. The case highlights the need for continuing ultrasonographic surveillance of fetuses with gastroschisis to identify further associated complications which were hitherto absent but whose presence may influence the timing of delivery and neonatal care.

Characterization and specificity of lipoprotein binding to term human placental membranes.

The binding characteristics of very-low-density (VLDL), low-density (LDL) and high-density (HDL) lipoprotein fractions to a purified human term placental microvillous membrane preparation were determined. Binding of LDL was saturable with a maximal binding capacity of 270 ng LDL protein per mg of membrane protein. Scatchard analysis revealed the presence of a single population of 3.4 X 10(11) sites per mg of membrane protein and a mean affinity constant of 5.8 X 10(-9) M. Binding of VLDL was also saturable but the maximal capacity was 4.5-times greater than that of LDL. The Scatchard analysis revealed the presence of 2.1 X 10(11) binding sites and an affinity constant nearly one order of magnitude greater than that of LDL. Binding of HDL showed less tendency to saturate. Scatchard analysis showed a similar number of receptor sites to that calculated for VLDL and LDL but the affinity constant for HDL was over 100-fold less than that of VLDL. Self- and cross-inhibition studies of VLDL and LDL binding revealed that VLDL was better at blocking the binding of LDL than was LDL itself. This preferential binding of VLDL suggests that this lipoprotein fraction could be an important source of cholesterol for placental progesterone production.

Ritodrine-induced pulmonary oedema in labour. Successful management using epidural anaesthesia.

A case is described in which unusually high doses of intravenous ritodrine were used for 6 weeks to postpone premature labour. Treatment was complicated by tachydysrhythmias and pulmonary oedema. Epidural analgesia was used successfully for pain relief during labour and Caesarean section. The pathophysiology is discussed.