Selective intrauterine growth restriction in monochorionic diamniotic twin pregnancies

Selective intrauterine growth restriction (sIUGR) occurs in 10 to 15% of monochorionic (MC) twins, and it is associated with a substantial increase in perinatal mortality and morbidity. Clinical evolution is largely influenced by the existence of intertwin placental anastomoses: pregnancies with similar degrees of fetal weight discordance are associated with remarkable differences in clinical behavior and outcome. We have proposed a classification of sIUGR into three types according to umbilical artery (UA) Doppler findings (I-normal, II-absent/reverse end-diastolic flow, III-intermittent absent/reverse end-diastolic flow), which correlates with distinct clinical behavior, placental features and may assist in counseling and management. In terms of prognosis, sIUGR can roughly be divided in two groups: type I cases, with a fairly good outcome, and types II and III, with a substantial risk for a poor outcome. Management of types II and III may consist in expectant management until deterioration of the IUGR fetus is observed, with the option of cord occlusion if this occurs before viability. Alternatively, active management can be considered electively, including cord occlusion or laser coagulation. Both therapies seem to increase the chances of intact survival of the larger fetus, while they entail, or increase the chances of, intrauterine demise of the IUGR fetus. Copyright © 2010 John Wiley & Sons, Ltd.     

Intrauterine rescue transfusion in monochorionic multiple pregnancies with recent single intrauterine death

To assess the role of fetal blood sampling and intrauterine transfusion in monochorionic (MC) multiple pregnancy complicated by single intrauterine death (IUD), we reviewed ten cases over a 4-year period in a tertiary referral centre which underwent fetal blood sampling within 24 h of death of its MC co-twin. Intrauterine rescue transfusion was performed in all seven anaemic fetuses (hematocrit; Hct<30%) to raise the fetal Hct to ≥40%. The rationale was to prevent death and/or brain injury. Two fetuses, which were severely acidaemic at blood sampling, died in utero within 24 h of the procedure. In two cases, the surviving twins manifested abnormal sonographic findings of the fetal brain 2–5 weeks later and underwent late termination. In two cases, the pregnancies continued uneventfully until delivery at 35 and 40 weeks' gestation with good neonatal outcome. In one case the co-twin delivered 1 week later at 29 weeks but died within 12 h. Fetuses without anaemia were not transfused and had normal clinical outcomes. We suggest that intrauterine rescue transfusion before the development of severe acidaemia in anaemic surviving MC co-twins may prevent fetal death, but does not necessarily prevent brain injury. Until its role becomes clearer, we recommend that its use be restricted to situations in which the parents and the local jurisdiction allow late termination as an option if brain injury subsequently manifests on ultrasound. Copyright © 2001 John Wiley & Sons, Ltd.     

Aortic isthmus Doppler velocimetry: role in assessment of preterm fetal growth restriction

Intrauterine fetal growth restriction (IUGR) is an important pregnancy complication associated with significant adverse clinical outcome, stillbirth, perinatal morbidity and cerebral palsy. To date, no uniformly accepted management protocol of Doppler surveillance that reduces mortality and cognitive morbidity has emerged. Aortic isthmus (AoI) evaluation has been proposed as a potential monitoring tool for IUGR fetuses. In this review, the current knowledge of the relationship between AoI Doppler velocimetry and preterm fetal growth restriction is reviewed. Relevant technical aspects and reproducibility data are reviewed as we discuss AoI Doppler and its place within the existing repertoire of Doppler assessments in placental insufficiency. The AoI is a link between the right and left ventricles which perfuse the lower and upper body, respectively. The clinical use of AoI waveforms for monitoring fetal deterioration in IUGR has been limited, but preliminary work suggests that abnormal AoI impedance indices are an intermediate step between placental insufficiency-hypoxemia and cardiac decompensation. Further prospective studies correlating AoI indices with arterial and venous Doppler indices and perinatal outcome are required before encorporating this index into clinical practice. Copyright © 2010 John Wiley & Sons, Ltd.     

Accuracy of ultrasound diagnoses in pregnancies complicated by suspected fetal anomalies

Referral of pregnancies complicated by suspected fetal anomalies to level III perinatal centres for further evaluation and management is increasing as use of real-time ultrasound spreads, but the sensitivity and specificity of the prenatal diagnoses made in this population are unknown. We undertook a prospective study that followed pregnancies referred to a designated programme dealing with suspected fetal abnormalities. Follow-up of 257 pregnancies revealed that 282 separate anomalies were accurately diagnosed in 212 cases. Normal anatomy was correctly predicted in 42 cases, 16 per cent of the referred population. False-positive and false-negative rates were 1·5 per cent (4/257) and 2 per cent (1/46), respectively. However, 37 per cent of those infants born with anomalies had additional problems not prenatally detected by ultrasound. These results indicate that prenatal ultrasound diagnoses are remarkably accurate overall but that they may be insensitive to associated anomalies in individual cases.     

Umbilical and uterine flow velocity waveforms in pregnancies complicated by major fetal anomalies

A continuous wave Doppler unit was used to obtain umbilical and uterine artery flow velocity waveforms in pregnancies complicated by a major fetal abnormality. A total of 139 examinations were performed on 32 women between 26 to 41 weeks' gestation, and the records were reviewed to determine the changes associated with fetal malformation. The systolic/diastolic (A/B) ratio was used as an index of blood flow resistance in the umbilical artery and the systolic minus diastolic divided by systolic (A–B)/A for the branches of the uterine artery. Seventeen out of 32 patients showed high systolic/diastolic ratio in waveforms taken from the umbilical artery. In 30 out of 32 patients the uterine artery waveform was normal (in two patients the results were equivocal). It appears that a fetal mechanism may determine the changes in the umbilical placental circulation resulting in an umbilical artery pattern of high flow resistance in more than half of the patients with congenital anomalies.     

Perinatal outcome after selective fetal reduction in monochorionic twin pregnancies: A comparison of techniques over a 20-year period

Objective

To assess the perinatal outcome after fetal reduction in complicated monochorionic (MC) twin pregnancies by comparing different techniques.

Methods

A retrospective cohort study at a national referral center comparing data between four techniques: interstitial laser coagulation, radiofrequency ablation (RFA), fetoscopic laser coagulation (FLC) and bipolar cord coagulation (BCC). The primary outcome was the mortality of the co-twins. Secondary outcomes were preterm pre-labor rupture of membranes (PPROM), gestational age at delivery and neonatal morbidity.

Results

259 MC twin pregnancies underwent selective fetal reduction: 29 IL, 64 RFA, 85 FLC and 81 BCC. The perinatal mortality rate was 29% and fetal demise of the co-twins occurred in 19%. The lowest mortality rate was seen after BCC (17%, p = 0.012). PPROM occurred in 18% patients without significant differences between techniques. The mean gestational age at delivery in liveborn children was 35 weeks and did not differ between techniques. Severe cerebral injury and neonatal morbidity were reported in 4% and 14%, respectively, without significant differences between techniques.

Conclusions

Selective fetal reductions in MC twins are precarious procedures with an increased risk of perinatal mortality of the co-twins. Our results show the lowest mortality rates after BCC. However, high PPROM rates were seen irrespective of the technique.