Alyson Hunter

National University of Ireland, Galway, Gaillimh, Connaught, Ireland

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Publications (15)34.71 Total impact

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    ABSTRACT: To determine the cause of adverse perinatal outcome in fetal growth restriction(FGR) where umbilical artery Doppler(UA) was normal, as identified from the Prospective Observational Trial to Optimize Pediatric Health(PORTO). We compared cases of adverse outcome where UA Doppler was normal and abnormal.
    American journal of obstetrics and gynecology. 07/2014;
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    ABSTRACT: To evaluate the significance of an abnormal cerebroplacental ratio (CPR) in twin pregnancies.
    Archives of Disease in Childhood - Fetal and Neonatal Edition 06/2014; 99(Suppl 1):A1. · 3.45 Impact Factor
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    ABSTRACT: The aim of the Prospective Observational Trial to Optimize Pediatric Health in IUGR (PORTO) Study was to evaluate the optimal management of fetuses with estimated fetal weight (EFW) <10(th) centile. The objective of this secondary analysis was to describe the role of the cerebroplacental ratio (CPR) in the prediction of adverse perinatal outcome. Over 1,100 consecutive singleton pregnancies with IUGR were recruited over two years at seven centers, undergoing serial sonographic evaluation including multi-vessel Doppler measurement. CPR was calculated using the pulsatility (PI) and resistance (RI) indices of the middle cerebral (MCA) and umbilical artery (UA) Adverse perinatal outcome was defined as a composite of intraventricular haemorrhage, periventricular leukomalacia, hypoxic ischaemic encephalopathy, necrotizing enterocolitis, bronchopulmonary dysplasia, sepsis, and death. Data for CPR calculation was available in 881 cases which was performed at a mean gestational age of 33 weeks (IQR 28.7-35.9) Of the 146 cases with CPR <1, 18% (n=27) had an adverse perinatal outcome. This conferred an 11-fold increased risk (OR 11.7, p<0.0001) when compared to cases with normal CPR (2%; 14/735). An abnormal CPR was present in all 3 cases of mortality. Prediction of adverse outcomes was comparable when using all definitions of abnormal CPR. Irrespective of the CPR calculation employed, brainsparing is significantly associated with adverse perinatal outcome in IUGR. This adds further weight to integrating CPR evaluation into the clinical assessment of IUGR pregnancies. The impact of this finding on long term neurodevelopmental outcomes in this patient cohort is underway.
    American journal of obstetrics and gynecology 05/2014; · 3.28 Impact Factor
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    ABSTRACT: Intrauterine growth restriction (IUGR) is the single largest contributing factor to perinatal mortality in non-anomalous fetuses. Advances in antenatal and neonatal critical care have resulted in a reduction in neonatal deaths over the past decades, while stillbirth rates have remained unchanged. Antenatal detection rates of fetal growth failure are low, and these pregnancies carry a high risk of perinatal death. The Prospective Observational Trial to Optimize Paediatric Health in IUGR (PORTO) Study recruited 1,200 ultrasound-dated singleton IUGR pregnancies, defined as with EFW <10th centile, between 24+0 and 36+6 weeks gestation. All recruited fetuses underwent serial sonographic assessment of fetal weight and multi-vessel Doppler studies until birth. Perinatal outcomes were recorded for all pregnancies. Case records of the perinatal deaths from this prospectively recruited IUGR cohort were reviewed, their pregnancy details and outcome were analysed descriptively and compared to the entire cohort. Of 1,116 non-anomalous singleton infants with EFW <10th centile, 6 resulted in perinatal deaths including 3 stillbirths and 3 early neonatal deaths. Perinatal deaths occurred between 24+6 and 35+0 weeks gestation corresponding to birthweights ranging from 460 to 2260grams. Perinatal deaths occurred more commonly in pregnancies with severe growth restriction (EFW <3rd centile) and associated abnormal Doppler findings resulting in earlier gestational ages at delivery and lower birthweights. All of the described pregnancies were complicated by either significant maternal comorbidities, e.g. hypertension, systemic lupus erythematosus (SLE) or diabetes, or poor obstetric histories, e.g. prior perinatal death, mid-trimester or recurrent pregnancy loss. Five of the 6 mortalities occurred in women of non-Irish ethnic backgrounds. All perinatal deaths showed abnormalities on placental histopathological evaluation. The PNMR in this cohort of prenatally identified IUGR cases was 5.4/ 1,000 and compares favourably to the overall national rate of 4.1/ 1,000 births, which can be attributed to increased surveillance and timely delivery. Despite antenatal recognition of IUGR and associated maternal risk factors, not all perinatal deaths can be prevented.
    BMC Pregnancy and Childbirth 02/2014; 14(1):63. · 2.52 Impact Factor
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    ABSTRACT: Fetal Doppler evaluation forms an important part of twin pregnancy assessment, however no twin-specific fetal Doppler centiles are available for clinical practice. To construct monochorionic and dichorionic twin reference ranges for umbilical artery (UA) pulsatility index (PI), UA resistance index (RI), middle cerebral artery (MCA) PI and peak systolic velocity (PSV) and cerebroplacental ratio (CPR) from 24 weeks' to 38 weeks' gestation and compare these to published normative values for singleton pregnancies. This prospective multicentre cohort study included 1,028 unselected twin pairs recruited over a 2 year period. Participants with dichorionic twins underwent two weekly ultrasound surveillance from 24 weeks' gestation with monochorionic twins being followed every two week from 16 weeks' gestation until delivery. The UA PI and RI appear to be higher in twins in comparison to singletons. The MCA PI and PSV appear to be lower. The CPR also appears to be lower in twins compared with singletons. Monochorionic diamniotic (MCDA) and dichorionic (DC) twins exhibited similar MCA indices. We have established longitudinal reference ranges for UA PI and RI, MCA PI, PSV and cerebroplacental ratio in twin pregnancies which appear to differ from singleton reference ranges. These reference ranges may be more appropriate in the surveillance of these high risk pregnancies. Applying the singleton CPR cut-off of ≤ 1.0 may lead to a large number of false positive diagnoses of cerebral redistribution in twin fetuses.
    Ultrasound in Obstetrics and Gynecology 01/2014; · 3.56 Impact Factor
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    ABSTRACT: To evaluate opinions among Irish obstetricians and obstetric trainees regarding the optimal definition, assessment and management of pregnancies affected by intrauterine growth restriction (IUGR). An anonymous, structured, web-based survey that comprised 14 questions was sent to 200 obstetricians and obstetric trainees in Ireland. Of the 113 participants (57% response rate), the majority (50%) were consultants, with over 10 years' clinical experience (46%), who worked in large maternity units (58%) with neonatal units providing care for preterm IUGR fetuses (94%). Eighty-three clinicians (74%) agreed that an estimated fetal weight (EFW) below the 10th centile constitutes small-for-gestational age (SGA). The majority (n=93; 82%) would deliver the SGA fetus between 37(+0) and 39(+6) weeks gestation. In total, the survey yielded 30 different IUGR definitions; the top three definitions were (i) an EFW below the 5th centile (n=18; 16%), (ii) an EFW below the 10th centile with oligohydramnios and abnormal umbilical artery (UA) Doppler (n=16; 14%), and (iii) an EFW below the 10th centile (n=12; 11%). In the evaluation of the preterm IUGR fetus with abnormal UA Doppler, the assessment of amniotic fluid volume, middle cerebral artery, ductus venosus, cardiotocograph (CTG) and biophysical profiling was performed in 74%, 60%, 60%, 54% and 52% respectively. The majority of clinicians applied three or more assessment modalities and 60% referred to a maternal-fetal medicine (MFM) subspecialist. Interestingly, even among MFM subspecialists there was no common consistent management approach. Most doctors (81%) would deliver the IUGR fetus for CTG abnormalities but MFM subspecialists more commonly deliver on the basis of absent end-diastolic flow in the UA alone (37% vs. 10%; p=0.006). Two-thirds of doctors (n=74) would implement customised growth charts if they became available for their population and over 80% thought that a national guideline on IUGR would be beneficial. The results of this survey confirm the inconsistencies surrounding the clinical management of IUGR pregnancies and highlight the need for standardisation of terminology and antenatal surveillance, implementation of fetal weight customisation and national guidance for Ireland.
    European journal of obstetrics, gynecology, and reproductive biology 12/2013; · 1.97 Impact Factor
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    ABSTRACT: Sonographic estimation of fetal weight (EFW) is important in the management of high-risk pregnancies. The possibility that increased maternal body mass index (BMI) adversely affects EFW assessments in twin pregnancies is controversial. The aim of this study was to investigate the effect of maternal BMI on the accuracy of EFW assessments in twin gestations prospectively recruited for the ESPRiT (Evaluation of Sonographic Predictors of Restricted growth In Twins) study. 1001 twin pair pregnancies were recruited. After exclusion, BMI, birthweights, and ultrasound determination of EFW (within 2 weeks of delivery) were available for 943 twin pairs. The accuracy of EFW determination was defined as the difference between EFW and actual birthweight for either twin (absolute difference and percent difference). Cells with < 5% of the population were combined for analysis resulting in the following three maternal categories: 1.Normal/Underweight; 2.Overweight; and 3.Obese/Extremely Obese. Analysis of the three categories revealed mean absolute variation values of 184 grams (8.0%) in the normal / underweight group (n=531), 196 grams (8.5%) in the overweight group (n=278) and 206 grams (8.6%) in the obese/ extremely obese group (n=134)(p-value = 0.028, non-significant after adjustment for multiple testing). Regression analysis showed no linear or log-linear relationship between BMI and the accuracy of EFW (p-value for absolute difference=0.11, p-value for percentage difference=0.27). Contrary to a commonly held clinical impression, increasing maternal BMI has no significant impact on the accuracy of EFW estimations in twin pregnancy.
    American journal of obstetrics and gynecology 11/2013; · 3.28 Impact Factor
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    ABSTRACT: An objective of the PORTO Study was to evaluate multi-vessel Doppler changes in a large cohort of IUGR fetuses to establish whether a predictable progressive sequence of Doppler deterioration exists and to correlate these Doppler findings with respective perinatal outcomes. Over 1,100 unselected consecutive ultrasound-dated singleton pregnancies with EFW<10th centile were recruited between January 2010 and June 2012. Eligible pregnancies were assessed by serial Doppler interrogation of umbilical (UA) and middle cerebral (MCA) arteries, ductus venosus (DV), aortic isthmus (AoI) and myocardial performance index (MPI). Intervals between Doppler changes and patterns of deterioration were recorded and correlated with respective perinatal outcomes. Our study of 1,116 non-anomalous fetuses comprised 7,769 individual Doppler datapoints. 511 (46%) patients had an abnormal UA, 300 (27%) had an abnormal MCA and 129 (11%) had an abnormal DV Doppler. The classic pattern from abnormal UA to MCA to DV existed but no more frequently than any of the other potential pattern. Doppler interrogation of the UA and MCA remains the most useful and practical tool in identifying fetuses at risk of adverse perinatal outcome, capturing 88% of all adverse outcomes. In contrast to previous reports, we have demonstrated multiple potential patterns of Doppler deterioration in this large prospective cohort of IUGR pregnancies which calls into question the usefulness of multi-vessel Doppler assessment to inform frequency of surveillance and timing of delivery of IUGR fetuses. These data will be critically important for planning any future intervention trials.
    American journal of obstetrics and gynecology 08/2013; · 3.28 Impact Factor
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    ABSTRACT: To examine the validity of a growth trajectory method to discriminate between pathologically and constitutionally undergrown fetuses using repeated measures of estimated fetal weight. In a prospective, observational, multicenter study in Ireland, 1,116 women with a growth-restricted fetus diagnosed participated with the objective of evaluating ultrasound findings as predictors of pediatric morbidity and mortality. Fetal growth trajectories were based on estimated fetal weight. Between 22 weeks of gestation and term, two fetal growth trajectories were identified: normal (96.7%) and pathologic (3.3%). Compared with the normal trajectory, the pathologic trajectory was associated with an increased risk for preeclampsia (odds ratio [OR] 8.1, 95% confidence interval [CI] 2.6-23.4), increased umbilical artery resistance at 30 weeks of gestation (OR 12.6, 95% CI 4.6-34.1) or 34 weeks of gestation (OR 28.0, 95% CI 8.9-87.7), reduced middle cerebral artery resistance at 30 weeks of gestation (OR 0.33, 95% CI 0.12-0.96) or 34 weeks of gestation (OR 0.14, 95% CI 0.03-0.74), lower gestational age at delivery (mean 32.02 weeks of gestation compared with 38.02 weeks of gestation; P<.001), and higher perinatal complications (OR 21.5, 95% CI 10.5-44.2). In addition, 89.2% of newborns with pathologic fetal growth were admitted to neonatal intensive care units compared with 25.9% of those with normal growth. Fetal growth trajectory analysis reliably differentiated fetuses with a pathologic growth pattern among a group of women with growth-restricted fetuses. With further development, this approach could provide clarity to how we define, identify, and ultimately manage pathologic fetal growth. LEVEL OF EVIDENCE:: II.
    Obstetrics and Gynecology 08/2013; 122(2, PART 1):248-254. · 4.80 Impact Factor
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    ABSTRACT: Abstract Objective: To compare the outcomes of twin pregnancies conceived by artificial reproductive techniques (ART) with those of spontaneous conception. Study design: In this multicenter prospective trial, comparisons were made between methods of conception in twin pregnancies, for maternal and perinatal outcomes. Results: Of 1001 twin pairs, 763/1001 (72.7%) were spontaneously conceived and 238/1001(27.3%) were conceived by ART. There were no significant differences between the two groups with respect to obstetric complications. There were 13 per 1000 (20/1504; 1%) perinatal deaths in the spontaneously conceived group and 6 per 1000 (3/466; 0.6%) in the ART group (p = 0.8141). We found no differences in gestational age at delivery (median 36.9 versus 37.0 weeks), birth weight (median 2520 g versus 2538 g), or in a composite measure of adverse perinatal outcome (17% versus 15%) between the groups. Conclusion: There were no differences in the rate of adverse obstetric or perinatal outcomes between twins conceived naturally compared with twins conceived by assisted conception.
    The journal of maternal-fetal & neonatal medicine: the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstetricians 07/2013; · 1.36 Impact Factor
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    ABSTRACT: The objective of the Prospective Observational Trial to Optimize Pediatric Health in Intrauterine Growth Restriction (IUGR) (PORTO Study), a national prospective observational multicenter study, was to evaluate which sonographic findings were associated with perinatal morbidity and mortality in pregnancies affected by growth restriction, originally defined as estimated fetal weight (EFW) <10th centile. Over 1100 consecutive ultrasound-dated singleton pregnancies with EFW <10th centile were recruited from January 2010 through June 2012. A range of IUGR definitions were used, including EFW or abdominal circumference <10th, <5th, or <3rd centiles, with or without oligohydramnios and with or without abnormal umbilical arterial Doppler (pulsatility index >95th centile, absent or reversed end-diastolic flow). Adverse perinatal outcome, defined as a composite outcome of intraventricular hemorrhage, periventricular leukomalacia, hypoxic ischemic encephalopathy, necrotizing enterocolitis, bronchopulmonary dysplasia, sepsis, and death was documented for all cases. Of 1116 fetuses, 312 (28%) were admitted to neonatal intensive care unit and 58 (5.2%) were affected by adverse perinatal outcome including 8 mortalities (0.7%). The presence of abnormal umbilical Doppler was significantly associated with adverse outcome, irrespective of EFW or abdominal circumference measurement. The only sonographic weight-related definition consistently associated with adverse outcome was EFW <3rd centile (P = .0131); all mortalities had EFW <3rd centile. Presence of oligohydramnios was clinically important when combined with EFW <3rd centile (P = .0066). Abnormal umbilical artery Doppler and EFW <3rd centile were strongly and most consistently associated with adverse perinatal outcome. Our data call into question the current definitions of IUGR used. Future studies may address whether using stricter IUGR cutoffs comparing various definitions and management strategies has implications on resource allocation and pregnancy outcome.
    American journal of obstetrics and gynecology 04/2013; 208(4):290.e1-6. · 3.28 Impact Factor
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    ABSTRACT: Background: The Prenatal Distress Questionnaire (PDQ) is a short measure designed to assess specific worries and concerns related to pregnancy. The aim of this study was to confirm the factor structure of the PDQ in a group of pregnant women with a small for gestational age infant (Methods: The first PDQ assessment for each of 337 pregnant women participating in the Prospective Observational Trial to Optimise paediatric health (PORTO) study was analysed. All women enrolled in the study were identified as having a small for gestational age foetus (Results: The three-factor model offered the best fit to the data while maintaining sound theoretical grounds(χ2 (51df) = 128.52; CFI = 0.97; TLI = 0.96; RMSEA = 0.07). Factor 1 contained items reflecting concerns about birth and the baby, factor 2 concerns about physical symptoms and body image and factor 3 concerns about emotions and relationships. Conclusions: CFA confirmed that the three-factor model provided the best fit, with the items in each factor reflecting the findings of an earlier exploratory data analysis.
    Journal of Reproductive and Infant Psychology 01/2013; 31(5). · 0.67 Impact Factor
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    ABSTRACT: We sought to evaluate the association between placental histological abnormalities and birthweight discordance and growth restriction in twin pregnancies. 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. 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. 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.
    American journal of obstetrics and gynecology 07/2012; 207(3):220.e1-5. · 3.28 Impact Factor
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    American Journal of Obstetrics and Gynecology. 208(1):S15.
  • American Journal of Obstetrics and Gynecology. 208(1):S13–S14.