Sarah Bower

Middle cerebral artery flow velocity waveforms in fetal hypoxaemia

Summary. In 81 small‐for‐gestational age fetuses (SGA) colour flow imaging was used to identify the fetal middle cerebral artery for subsequent pulsed Doppler studies. Impedence to flow (pulsatility index; PI) was significantly lower, and mean blood velocity was significantly higher, than the respective reference ranges with gestation. Fetal blood sampling by cordocentesis was performed in all SGA fetuses and a significant quadratic relation was found between fetal hypoxaemia and the degree of reduction in the PI of FVWs from the fetal middle cerebral artery. Thus, maximum reduction in PI is reached when the fetal PO2 is 2‐4 SD below the normal mean for gestation. When the oxygen deficit is greater there is a tendency for the PI to rise, and this presumably reflects the development of brain oedema.

Doppler ultrasound screening as part of routine antenatal scanning: prediction of pre‐eclampsia and intrauterine growth retardation

Objective To assess the value of incorporating continuous wave Doppler ultrasound of the uterine arteries into the routine scan as a screening test in an unselected population.

Computerized fetal heart rate analysis, Doppler ultrasound and biophysical profile score in the prediction of acid-base status of growth-restricted fetuses

To investigate the performance of non‐stress test (NST), computerized fetal heart rate analysis (cCTG), biophysical profile scoring (BPS) and arterial and venous Doppler ultrasound investigation in the prediction of acid–base status in fetal growth restriction.

Maternal abdominal pressure alters fetal cerebral blood flow

The aim of this study was to examine systematically the effect of fetal head compression caused by the ultrasound transducer on flow velocity wavaforms from the middle cerbral and internal carotid arteries. Minimal transducer pression should be exerced during doppler examination of foetal head to avoid an artefactual increase of impedence to blood flow, and thus, a high false negative rate in the detection of foetal hypoxia.

Prediction of miscarriage and stillbirth at 11–13 weeks and the contribution of chorionic villus sampling

To derive models for estimating risk of miscarriage and stillbirth from maternal characteristics and findings of first‐trimester screening for aneuploidies and to define the procedure‐related risk of chorionic villus sampling (CVS) after adjusting for these factors.

Cerebral and renal artery blood flow velocity before and after birth

OBJECTIVEnTo document perinatal changes in cerebral and renal artery haemodynamics in premature growth-retarded and normal term infants.nnnDESIGNnLongitudinal study of individual infants. Doppler ultrasound measurements of blood flow velocity (BFV) in the middle cerebral and renal arteries were obtained before delivery, soon after delivery and during the first week of postnatal life.nnnSETTINGnTeaching hospital obstetric and neonatal units.nnnSUBJECTSn13 severely growth retarded infants born at 28-36 weeks gestation, and eight normally grown infants born at term.nnnRESULTSnIn both groups, BFV in the cerebral artery was significantly lower in the first few hours after birth than in fetal life, but subsequently increased to reach pre-delivery values by the end of the first week. In contrast, BFV in the renal artery during the first postnatal day was not significantly different from fetal values, but it also increased during the subsequent week. In six of the preterm growth-retarded infants, fetal blood gases were measured in samples obtained by cordocentesis, and in these cases an increase in blood oxygen content at birth was documented.nnnCONCLUSIONSnCerebral artery BFV falls at birth and is relatively low during the time that premature infants are at the greatest risk of developing periventricular haemorrhage.

Monochorionic diamniotic twin pregnancy with selective fetal growth restriction Type II: sonographic and fetoscopic findings of poor prognosis

Monochorionic diamniotic (MCDA) twin pregnancies pose a challenge for the fetal medicine specialist in terms of diagnosis and management, largely attributable to complications arising from a shared placental circulation. About 95% of MC twins have vascular anastomoses on the placental surface that connect the two circulations. The almost continuous blood exchange between these twins accounts for unique complications, including twin-to-twin transfusion syndrome, twin anemia–polycythemia sequence and twin reversed-arterial perfusion sequence1. This should be borne in mind when considering options for management in cases complicated by selective fetal growth restriction (sFGR). We describe here the sonographic and fetoscopic findings in a MCDA twin pregnancy with sFGR. A 23-year-old primigravida with spontaneous MCDA twin pregnancy was referred to our unit at 16 weeks of gestation due to a marked discrepancy in growth between the fetuses. In the first trimester, the discrepancy in nuchal translucency was not marked (1.7 mm vs 1.9 mm) but the intertwin difference in crown–rump length was 22% (63.4 mm vs 80.4 mm). At 17 weeks, the discrepancy between fetuses in estimated fetal weight (EFW) was 45%. Doppler assessment showed abnormal flow in both umbilical arteries, reversed a-wave in the ductus venosus of the smaller twin (Figure 1) but normal findings in the cotwin, prompting a diagnosis of sFGR Type II. In view of the rapid deterioration of the smaller twin and the high chance of intrauterine demise, laser separation of the placental circulations was recommended in order to avoid exsanguination of the healthy twin through the placental anastomoses. Fetoscopic surgery was performed uneventfully under local anesthesia.

OC112: Integrated fetal testing most accurately predicts perinatal outcome in intrauterine growth restriction (IUGR)

Objective: Longitudinal measurements of quantitative flow (QF) could clarify compensatory mechanisms to fetal hypoxia, and suggest predictive factors of fetal decompensation and adverse outcome. Our aims were to analyse in IUGR fetuses longitudinal changes of QF in umbilical vein (UV), ductus venosus (DV) and left cardiac output (LCO) and to identify which cardiovascular pattern is more frequently associated with adverse outcome. Methods: In 33 IUGR fetuses, two consecutive examinations were retrospectively considered: the last scan (LAST) within 3 days before delivery and the previous exam (FIRST) within 8 days before LAST. Doppler QF was measured at three different sites: intraamniotic UV, DV and ascending aorta, according to a standardized methodology. QF changes were compared between alive babies and perinatal deaths. A subset of viable fetuses delivered between 28 to 32 weeks was separately considered. QF changes suggestive of fetal decompensation (UV flow reduction, DV dilatation, DV flow increase, LCO reduction) were considered as a variation >10% from FIRST and LAST examination. Timing of delivery was independently decided by the clinical staff. Results: The gestational age at delivery was 29 ± 3.5 weeks (mean ± SD); the weight at delivery was 880 ± 450 g (mean ± SD).

OC113: Abnormal ductus venosus Doppler independently predicts poor perinatal outcome in fetuses delivered for severe early placental insufficiency: a multicenter cohort study

Objective: Longitudinal measurements of quantitative flow (QF) could clarify compensatory mechanisms to fetal hypoxia, and suggest predictive factors of fetal decompensation and adverse outcome. Our aims were to analyse in IUGR fetuses longitudinal changes of QF in umbilical vein (UV), ductus venosus (DV) and left cardiac output (LCO) and to identify which cardiovascular pattern is more frequently associated with adverse outcome. Methods: In 33 IUGR fetuses, two consecutive examinations were retrospectively considered: the last scan (LAST) within 3 days before delivery and the previous exam (FIRST) within 8 days before LAST. Doppler QF was measured at three different sites: intraamniotic UV, DV and ascending aorta, according to a standardized methodology. QF changes were compared between alive babies and perinatal deaths. A subset of viable fetuses delivered between 28 to 32 weeks was separately considered. QF changes suggestive of fetal decompensation (UV flow reduction, DV dilatation, DV flow increase, LCO reduction) were considered as a variation >10% from FIRST and LAST examination. Timing of delivery was independently decided by the clinical staff. Results: The gestational age at delivery was 29 ± 3.5 weeks (mean ± SD); the weight at delivery was 880 ± 450 g (mean ± SD).