Stephen Carroll

Prediction of chorionicity in twin pregnancies at 10–14 weeks of gestation

Objective To examine the accuracy of sonographic determination of chorionicity in twin pregnancies at 10–14 weeks of gestation.

Analysis of outcome in hydrops fetalis in relation to gestational age at diagnosis, cause and treatment.

Objective. To examine fetal outcome in hydrops fetalis in relation to gestational age at diagnosis and following investigation and treatment.

Placental cord insertion and birthweight discordance in twin pregnancies: results of the national prospective ESPRiT Study

OBJECTIVE The purpose of this study was to evaluate the impact of noncentral placental cord insertion on birthweight discordance in twins. STUDY DESIGN We performed a multicenter, prospective trial of twin pregnancies. Placental cord insertion was documented as central, marginal, or velamentous according to a defined protocol. Association of the placental cord insertion site with chorionicity, birthweight discordance, and growth restriction were assessed. RESULTS Eight hundred sixteen twin pairs were evaluated; 165 pairs were monochorionic, and 651 pairs were dichorionic. Monochorionic twins had higher rates of marginal (P = .0068) and velamentous (P < .0001) placental cord insertion. Noncentral placental cord insertion was more frequent in smaller twins of discordant pairs than control pairs (29.8% vs 19.1%; P = .004). Velamentous placental cord insertion in monochorionic twins was associated significantly with birthweight discordance (odds ratio, 3.5; 95% confidence interval, 1.3-9.4) and growth restriction (odds ratio, 4; 95% confidence interval, 1.1-14.3). CONCLUSION Noncentral placental cord insertion contributes to birthweight discordance in monochorionic twin pregnancies. Sonographic delineation of placental cord insertion may be of value in antenatal assessment of twin pregnancies.

Prediction of safe and successful vaginal twin birth

OBJECTIVE The objective of the study was to establish predictors of vaginal twin birth and evaluate perinatal morbidity according to mode of delivery. STUDY DESIGN One thousand twenty-eight twin pregnancies were prospectively recruited. For this prespecified secondary analysis, obstetric characteristics and a composite of adverse perinatal outcome were compared according to the success or failure of a trial of labor and further compared with those undergoing elective cesarean delivery. Perinatal outcomes were adjusted for chorionicity and gestational age using a linear model for continuous data and logistic regression for binary data. RESULTS Nine hundred seventy-one twin pregnancies met the criteria for inclusion. A trial of labor was considered for 441 (45%) and was successful in 338 of 441 (77%). The cesarean delivery rate for the second twin was 4% (14 of 351). Multiparity and spontaneous conception predicted vaginal birth. No statistically significant differences in perinatal morbidity were observed. CONCLUSION A high prospect of successful and safe vaginal delivery can be achieved with trial of twin labor.

Ultrasound-guided, intra-abdominal laser to treat acardiac pregnancies

A 19 year old woman in her first pregnancy at 18 weeks of gestation was referred to the fetal medicine unit because of an abnormal twin pregnancy in which it was believed that one of the fetuses had died. At ultrasound examination, there was one live fetus whose measurements were consistent with gestational age by her last menstrual period, with no obvious fetal abnormalities except a single umbilical artery. There were no signs of hydrops although the umbilical artery Doppler pulsatility index was elevated at 1.73, and there was a full bladder with a moderate increase in the amniotic fluid volume (amniotic fluid index 1⁄4 25.2 cm). No heart action was present in the other fetus, which was extremely hydropic and the lower body was more developed than the upper body. No face, neck or arms could be identified and the body consisted of a chest, abdomen and relatively well-developed legs, which showed movements. The diagnosis of an acardiac twin pregnancy was made. Perfusion at the cord insertion was demonstrated and using colour Doppler it was possible to identify that the blood was moving away from the acardiac twin via the umbilical vein and towards it in the umbilical arteries. The woman was told of the findings and the overall poor prognosis of this condition. She was given the options of either doing nothing with a high risk of preterm delivery, having laser coagulation of the acardiac fetal circulation or having a termination of pregnancy. She chose laser ablation, which was performed a week later. After infiltration of local anaesthetic into the maternal abdomen, a 17-gauge chorion villus sampling needle was passed into the abdomen of the acardiac twin under ultrasound guidance (Aspen, Acuson, Mountain View, California, USA) until its tip was in close proximity to the superior vesical arteries, as identified by colour Doppler. A laser fibre of 1.05 mm diameter (Surgical Laser Technologies, Philadelphia, Pennsylvania, USA) connected to a neodymium yttrium aluminium garnet laser (Surgical Laser Technologies, Philadelphia, Pennsylvania, USA) was then passed through the needle under ultrasound-guidance and the superior vesical arteries on both sides of the bladder were coagulated using pulses of 20 W to 30 W lasting three to five seconds until there was no visible flow on colour Doppler. The entire procedure lasted twenty minutes and the fetal heart rate of the other twin remained normal throughout the procedure. Subsequent serial scans showed normal growth, umbilical artery pulsatility index and amniotic fluid volume in the sac of the surviving fetus. In addition, no abnormalities of the brain were detected. Although the acardiac twin remained visible, it did not grow and no blood flow could be demonstrated within it at any time. Labour was induced at 38 weeks of gestation, and the woman had a vaginal delivery of a 3.52 kg well baby boy. Postnatal cranial ultrasound and magnetic resonance imaging of the brain of the baby were normal and at 18 months of age the child is developmentally normal. Postmortem examination of the acardiac twin, which was severely macerated, confirmed the ultrasound findings and in addition, the foot length was consistent with 17–18 weeks of gestation. It was not possible to identify the ablated superior vesical arteries during the internal examination or the site of insertion of the umbilical cord of the acardiac fetus into the placenta.

Placental pathology, birthweight discordance, and growth restriction in twin pregnancy: results of the ESPRiT Study.

OBJECTIVE We sought to evaluate the association between placental histological abnormalities and birthweight discordance and growth restriction in twin pregnancies. STUDY DESIGN We performed a multicenter, prospective study of twin pregnancies. Placentas were examined for evidence of infarction, retroplacental hemorrhage, chorangioma, subchorial fibrin, or abnormal villus maturation. Association of placental lesions with chorionicity, birthweight discordance, and growth restriction were assessed. RESULTS In all, 668 twin pairs were studied, 21.1% monochorionic and 78.9% dichorionic. Histological abnormalities were more frequent in placentas of smaller twins of birthweight discordant pairs (P = .02) and in placentas of small for gestational age infants (P = .0001) when compared to controls. The association of placental abnormalities with both birthweight discordance and small for gestational age was significant for dichorionic twins (P = .01 and .0001, respectively). No such association was seen in monochorionic twins. CONCLUSION In a large, prospective, multicenter study, we observed a strong relationship between abnormalities of placental histology and birthweight discordance and growth restriction in dichorionic, but not monochorionic, twin pregnancies.

Parvovirus as a Differential Diagnosis of Hydrops fetalis in the First Trimester

We report a case of fetal parvovirus B19 infection which appears to have resulted in hydrops in the first trimester. An ultrasound scan performed at the booking visit of a woman in the first trimester showed generalised oedema. Karyotyping to exclude a fetal abnormality was normal. Maternal radioimmunoassay serological investigations showed parvovirus B19 IgG and IgM. Post-mortem analysis revealed intranuclear inclusion bodies typical of parvovirus in the erythroid cells in the liver and in the myocardium.

Fetal death in twins

Objective. To examine the pattern and prospective risk of intrauterine fetal death (IUFD) in twin pregnancy by chorionicity. Design. Retrospective cohort analysis. Setting. Large national tertiary referral center. Population. All consecutive twin deliveries (1997–2006) ≥24 weeks. Methods. Retrospective review of all consecutive twin deliveries over 10 years to identify patterns of IUFD in twins and calculate gestation‐specific prospective risks of IUFD. Fetal death was defined as intrauterine demise of a fetus ≥24weeks, intertwin birthweight discordance as ≥20% difference and growth restriction as birthweight <5th centile. Chorionicity was confirmed by postnatal placental examination. Main outcome measures. Fetal death. Results. 1094 twin pairs including 276 monochorionic‐diamniotic (MCDA) (25.3%) and 818 dichorionic‐diamniotic (DCDA) twin pregnancies (74.7%) were studied. Twenty‐nine fetal deaths occurred affecting 22 twin pregnancies. The incidence of IUFD (death of one or both fetuses) in MCDA twin pregnancies was three times that in DCDA pregnancies [11/276 (3.9)% vs. 11/818 (1.3%) p<0.001]. The majority of deaths in MCDA twins were associated with twin–twin transfusion syndrome (TTTS) prior to 30 weeks. In normally grown twins the prospective risk of IUFD was similarly low in MCDA and DCDA pregnancies after 34 weeks but in pregnancies complicated by abnormal growth, the prospective risk of IUFD was 3.4 in MCDA and 2.0 in DCDA pregnancies. Conclusion. Twin pregnancies complicated by growth restriction or growth discordance were associated with a high risk of IUFD, particularly in affected MCDA twins. Conversely, in normally grown twins the risk was similarly low in MCDA and DCDA pregnancies after 34 weeks.

Prenatal detection of structural cardiac defects and presence of associated anomalies: a retrospective observational study of 1262 fetal echocardiograms

The aim of this study is to document the detection of fetal congenital heart defect (CHD) in relation to the following: (1) indication for referral, (2) chromosomal and (3) extracardiac abnormalities.

Outcome following selective fetoscopic laser ablation for twin to twin transfusion syndrome: an 8 year national collaborative experience

OBJECTIVE With the recognition of the role of fetoscopic laser ablation for twin to twin transfusion syndrome (TTTS), there is a requirement for auditable standards for this technically challenging and specialized treatment. The purpose of this study is to report on the perinatal and medium-term neurodevelopmental outcomes following an 8-year national single center experience in the management of TTTS using the selective fetoscopic laser ablation technique. STUDY DESIGN An audit of all cases of TTTS treated with selective laser ablation by a single national fetal medicine team was performed. Overall perinatal survival and medium-term neurodevelopmental outcomes were reported and correlated with gestational age at diagnosis, placental location, volume of amnio-reduction, Quintero staging and percentage inter-twin growth discordance. Procedure-related complications were recorded. RESULTS The overall fetal survival for the first 105 consecutive cases of TTTS was 61% (128/210 fetuses). Dual survival occurred in 47% (49/105) of cases, and with a single survival rate of 28% (30/105), perinatal survival of least one infant was achieved in 75% (79/105) of cases. No correlation was found between any clinical or sonographic marker and perinatal outcome, although dual survival was noted to be significantly decreased with increasing Quintero stage (p=0.041). Currently, 86% of survivors have been reported to have a normal medium-term neurological outcome. CONCLUSION Fetoscopic laser ablation is the established optimal treatment for severe twin to twin transfusion syndrome (TTTS). We report comparable short and medium-term outcomes following the selective fetoscopic technique comparing results from our national program with internationally published single-center outcomes, supporting the efficacy and safety of this treatment at our center.