Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology
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Ultrasound Obstet Gynecol · Feb 1999
Individual growth patterns in the first trimester: evidence for difference in embryonic and fetal growth rates.
To evaluate individual fetal growth during the first trimester in pregnancies resulting from spontaneous and in vitro fertilization (IVF). ⋯ First-trimester growth studies in individual fetuses indicate that there is a change in length growth rate between 9 and 10 weeks, menstrual age. This is consistent with a shift in development from organogenesis to growth. These results can be used for more accurate assessment of first-trimester growth and may aid in the detection of fetal problems that manifest themselves as growth abnormalities.
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Ultrasound Obstet Gynecol · Feb 1999
The effects of maternal indomethacin therapy on human fetal branch pulmonary arterial vascular impedance.
To examine whether maternal indomethacin therapy affects human fetal pulmonary arterial vascular impedance without constriction of the ductus arteriosus and to determine the changes in the pulmonary arterial vascular impedance in the presence of ductal constriction. ⋯ Human fetal pulmonary arterial vascular impedance is increased by maternal indomethacin therapy even without ductal constriction. In the presence of ductal constriction, the magnitude of the increase in the vascular impedance is related to the gestational age.
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Ultrasound Obstet Gynecol · Dec 1998
Case ReportsA strategy for reducing the mortality rate from vasa previa using transvaginal sonography with color Doppler.
Vasa previa is a cause of sudden unanticipated fetal death, with a fetal mortality of 33-100%. Transvaginal sonography (TVS) and color Doppler may aid in making the diagnosis antenatally, allowing elective Cesarean delivery, thereby avoiding fetal death from exsanguination which would occur if the membranes were allowed to rupture in labor. Whilst it is not feasible to screen all pregnant women for vasa previa, antenatal examination with TVS and color Doppler of women at risk, specifically those with low-lying placentas, bi-lobed, multi-lobed and succenturiate-lobed placentas, multiple pregnancies and pregnancies resulting from in vitro fertilization may lead to antenatal diagnosis of the condition. ⋯ In all three cases, routine 20-week obstetric sonography revealed low-lying placentas; in only one of these did the placenta remain low at term. A low-lying placenta at 20 weeks may be a risk factor for vasa previa; we suggest that further studies be carried out to ascertain this. Judicious use of TVS and color Doppler in women considered at risk of vasa previa may help to reduce the mortality from this condition.
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Ultrasound Obstet Gynecol · Jul 1998
Arterial and venous Doppler velocimetry in the severely growth-restricted fetus and associations with adverse perinatal outcome.
To evaluate the association between arterial and venous Doppler waveforms and adverse perinatal outcome in severe intrauterine growth restriction. ⋯ Our data suggest that management of severely growth-restricted fetuses may be aided by the study of ductus venosus Doppler velocimetry.
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Ultrasound Obstet Gynecol · Jun 1998
Case ReportsSuggested ultrasound parameters for the assessment of fetal well-being during chronic hemodialysis.
There are no published guidelines on how to assess fetal well-being during hemodialysis. We have developed a specific protocol of renal and obstetric interventions to ensure that hemodialysis is associated with minimal changes in fetal status. ⋯ We found that, by strict adherence to these guidelines, there were no significant alterations in maternal mean arterial blood pressure, continuous fetal heart rate tracings, uterine artery systolic/diastolic ratios, or umbilical artery systolic/diastolic ratios. We conclude that stable uteroplacental and fetal perfusion can be maintained during chronic hemodialysis in pregnancy by adhering to a specific set of precautions.