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Biomedical subjects

N J Sebire

Publications and source records attributed to N J Sebire.

At least 91 records · Page 5Linked to original sources
PubMed2001

Is maternal underweight really a risk factor for adverse pregnancy outcome? A population-based study in London.

OBJECTIVE: To determine the maternal and fetal risk of adverse outcome during pregnancy in relation to low maternal body mass index in an unselected population. DESIGN: Retrospective analysis. METHODS: Information for the years between 1988 and 1997 was extracted from a validated maternity database, including all but one of the maternity units in the North West Thames Region; 215,105 completed singleton pregnancies were studied. Comparison of pregnancy outcome was made on the basis of maternal body mass index at booking. There were 176,923 with a normal weight body mass index ( = 20 < 25). There were 38,182 with an underweight body mass index (< 20). Comparisons included antenatal complications (e.g. gestational diabetes, pre-eclampsia); intervention in labour, maternal morbidities (e.g. infection, postpartum haemorrhage, pulmonary thromboembolism); and neonatal outcome (admitted to special care baby unit at 24 hour of age, gestation at delivery, birthweight, stillbirth). Data are presented as percentages of outcomes in the normal and underweight groups with adjusted odds ratios and confidence intervals according to body mass index group. RESULTS: In the underweight group only antenatal anaemia, preterm delivery and birthweight below the 5th centile were more frequent than in women of normal body mass index. The prevalence of certain complications, including development of gestational diabetes mellitus, pre-eclampsia, obstetric intervention and postpartum haemorrhage, were significantly lower in those with low body mass index. CONCLUSION: Low maternal body mass index is associated with increased prevalence of some pregnancy complications, notably preterm delivery and low birthweight, but overall the outcome is favourable and several adverse outcomes are less common in this group of women.

Body Mass Index↗
PubMed2001

Outcome for children born after in utero laser ablation therapy for severe twin-to-twin transfusion syndrome.

OBJECTIVE: To examine the postnatal development of a group of children born after in utero laser ablation therapy for severe twin-to-twin transfusion syndrome. DESIGN: Retrospective cohort outcome study involving assessment of neurodevelopment and physical well being. SETTING: Harris Birthright Centre, King's College Hospital, London. PARTICIPANTS: Twins and singleton survivors treated via laser ablation therapy for twin-to-twin transfusion syndrome over a four-year period. METHODS: Of 54 families contacted to participate in the study, who had been treated for twin-to-twin transfusion syndrome during a four-year period, 24 families attended for paediatric assessment; 12 pairs of twins and 12 singleton survivors were assessed for perinatal, neurological and neurodevelopmental outcome using the Griffiths scales of mental development. A further 20 families were assessed via a proforma after contact with their general practitioner. A comparison of these groups showed no significant differences in sociodemographic factors or severity of disease between responders (44 families, 81.5%) and non-responders (10 families). RESULTS: The group of children assessed by a paediatrician had low birthweight (1619g donor, 1814g recipient, 1877g singleton) and had been born preterm (33 weeks twins, 31.2 weeks singleton) with attendant increased resuscitation, neonatal unit admission (mean 40 days) and instrumental delivery. Mean Griffiths scores were within the normal range of ability (91.2 donor vs 97.7 recipient and 101.6 singletons) with the only significant difference being in the locomotor subscale where donor (82.6) and recipient (85.3) were less than singletons: -99.1 (P < 0.05). There was no cerebral palsy in the singleton survivors, but there were five cases in the twin group. All except one affected child (with quadriplegia) had mean Griffiths scores in the normal range. In the GP proforma group there was one case, in a twin, of cerebral palsy. CONCLUSION: The overall cerebral palsy rate was 9%: 0% in the singleton survivors group and 13.3% in the twin survivors group. This pilot data highlights the need for careful long term follow up of children affected by twin-to-twin transfusion syndrome.

Child, Preschool↗
PubMed2000

First trimester diagnosis of monoamniotic twin pregnancies.

This study reports the ultrasound findings and pregnancy outcome for a series of monoamniotic twin pregnancies diagnosed at 11-14 weeks' gestation. Of 315 monochorionic twin pregnancies examined, there were 12 (3.8%) monoamniotic, including four sets of conjoined twins (1.3%). The parents opted for termination of pregnancy in all cases of conjoined twins. In four other cases, there was discordancy for major structural fetal abnormality (kyphoscoliosis, anencephaly, body stalk defect, diaphragmatic hernia), and the cotwin was structurally normal. In the four cases in which both twins were structurally normal, ultrasound examination demonstrated normal nuchal translucency thickness in all cases but cord entanglement was demonstrated from the first trimester. Two cases were managed expectantly; one resulted in livebirth of both twins at 31 weeks' gestation and the second in intrauterine death of both fetuses at 21 weeks. Two pregnancies were treated with Sulindac; one resulted in a single intrauterine death at 30 weeks and delivery of a normal cotwin, the other, in intrauterine death of both fetuses at 31 weeks'. Monoamniotic twin pregnancies are associated with a high risk of fetal abnormalities and perinatal death and the mortality rate is higher than previously reported from series with recruitment later in gestation.

Crown-Rump Length↗
PubMed2000

Histomorphological features of chorionic villi at 10-14 weeks of gestation in trisomic and chromosomally normal pregnancies.

This study examines histomorphometric features in chorionic villi obtained by chorionic villus sampling (CVS) at 11-14 weeks of gestation from 124 ongoing pregnancies (38 with trisomy 21, 14 with trisomy 18, 11 with trisomy 13 and 61 chromosomally normal controls). In the trisomy 21 group there was an inverse relationship between fetal nuchal translucency thickness (NT) and villus diameter and number of capillaries per villus cross-section. In about half of the cases there was perivillous fibrinoid present, and the amount of this increased with gestation. Compared to the chromosomally normal group, in trisomy 18 the villus diameter was smaller and the number of capillaries per villus cross-section was reduced. In the trisomy 21 group, villi had an increased percentage of two layered trophoblast present and an increased proportion of villus capillaries with nucleated red blood cells present. In all three trisomies, but particularly in trisomies 18 and 13, both the amount of basophilic stippling of the basement membrane and the proportion of cases with stippling was increased. These results provide data on the possible mechanisms of increased fetal NT and on abnormal placental development in fetal trisomies.

Chorionic Villi↗
PubMed2000

Early prediction of severe twin-to-twin transfusion syndrome.

This extended series of 303 monochorionic twin pregnancies examined at 10-14 weeks gestation explores the possible association of increased fetal nuchal translucency thickness (NT) in the early prediction of severe twin-to-twin transfusion syndrome (TTS). Of 303 pregnancies, there were 16 in which at least one fetus was structurally or chromosomally abnormal and in the remaining 287 ongoing pregnancies there were 43 (15%) which developed severe TTS. The median fetal NT was 1.0 multiples of the median (MOM) and NT was >95th centile in 47 (8.2%) fetuses and in at least one fetus in 37 (12.9%) pregnancies. The prevalence of increased NT in the pregnancies that developed TTS [17.4% (n = 15) of fetuses and 28% (n = 12) of pregnancies] was significantly higher than in the non-TTS group [6.6% (n = 32) and 10.2% (n = 25) respectively; Z: = -3.4, P: < 0.001 and Z: = 3.2, P: < 0.001 respectively], likelihood ratio of increased fetal NT for prediction of TTS = 3.5 [95% confidence interval (CI) 1.9-6.2]. In 153 of the pregnancies, an ultrasound examination was also performed at 15-17 weeks gestation and intertwin membrane folding was seen in 49 (32%) cases; 21 of these (43%) subsequently developed TTS compared to two (1.9%) of the 104 pregnancies without membrane folding (Z: = 6.6, P: < 0.001), likelihood ratio of membrane folding for prediction of TTS = 4.2 (95% CI 3.0-6.0).

Diseases in Twins↗
PubMed1999

Increased nuchal translucency in trisomy 13 fetuses at 10-14 weeks of gestation.

In a multicenter screening study for trisomy 21 involving ultrasonographic measurement of fetal nuchal translucency thickness (NT) at 10-14 weeks of gestation, 100,311 singleton pregnancies with a live fetus were examined. There were 46 cases of trisomy 13, and in 33 (72%) of these, the NT was above the 95th centile. The estimated risk for trisomy 21, based on maternal age-related risk for this chromosomal abnormality and fetal NT, was above 1 in 300 in 37 (80.1%) of the trisomy 13 fetuses. The fetal crown-rump length was significantly reduced, but the fetal heart rate was increased, being above the 95th centile in 64% of cases. Additionally, 24% of trisomy 13 fetuses had holoprosencephaly and 10% had exomphalos. This study has demonstrated that at 10-14 weeks of gestation, about 80% of fetuses with trisomy 13 can be identified in a screening program for trisomy 21, based on a combination of maternal age and fetal NT.

Chromosomes, Human, Pair 13↗
PubMed1998

Intertwin disparity in fetal size in monochorionic and dichorionic pregnancies.

OBJECTIVE: To compare monochorionic and dichorionic pregnancies for intertwin disparities in fetal size. METHODS: Monochorionic and dichorionic pregnancies, recruited from an ultrasound screening study at 10-14 weeks' gestation, were compared for intertwin disparities in crown-rump length and birth weight. The disparities were expressed as a percentage of the values of the larger twin. RESULTS: The study population was 123 monochorionic and 416 dichorionic twin pregnancies. In the 104 monochorionic and 381 dichorionic pregnancies resulting in two live births, there were no significant differences in median (range) intertwin disparity in crown-rump length (4.3% [0-18.8%] and 3.4% [0-25.5%]) or birth weight (10.2% [0-37.0%] and 9.3% [0-49.2%]). To determine that the observed 0.9% intertwin differences in crown-rump length and birth weight between the two groups were significant at alpha = .05 with 80% power, we would have had to examine a minimum of 984 and 926 twin pregnancies, respectively, assuming that the proportion of monochorionic to dichorionic twins remained the same as in the current study. In addition, there was no significant correlation between intertwin disparities in crown-rump length and intertwin disparities in birth weight in either the monochorionic (P = .40, Rho = 0.02, 95% confidence interval [CI] -0.17, 0.22) or dichorionic group (P = .44, Rho = 0.01, 95% CI -0.11, 0.09). The median (range) intertwin disparity in crown-rump length in 15 dichorionic pregnancies with chromosomally abnormal fetuses (6.6% [0-24.0%]) and in 20 dichorionic pregnancies that ended in miscarriage or intrauterine death of one or both fetuses (7.7% [0-43.9%]) was significantly higher than in dichorionic pregnancies resulting in two live births (Z = 2.49 and 3.26, respectively, and P = .01 and .001, respectively). However, in 19 monochorionic twins with adverse pregnancy outcome there was no significant difference in median (range) intertwin disparity in crown-rump length (4.5% [0-20.0%]) from monochorionic pregnancies resulting in two live births (4.3% [0-18.8%]). To determine that the observed 0.2% difference in intertwin difference in crown-rump length between the two groups was significant at alpha = .05 with 80% power we would have had to examine a minimum of 5652 monochorionic twin pregnancies, assuming that the proportion in each group remained the same as in the current study. CONCLUSION: The findings of this study demonstrate that monochorionic and dichorionic twin pregnancies do not differ significantly in intertwin disparity in fetal size, either in early pregnancy or at birth.

Crown-Rump Length↗
PubMed1998

Screening for fetal abnormalities in multiple pregnancies.

Multiple gestations account for 1-2% of all pregnancies but contribute disproportionately to the incidence of both perinatal loss and fetal structural abnormalities. Ultrasound examination provides essential information about screening for, and the management of, such defects, including accurate determination of chorionicity, assessment of risk, invasive testing and selective termination if appropriate.

Chorion↗
PubMed1998

Inter-twin membrane folding in monochorionic pregnancies.

This study examines the value of assessing inter-twin membrane folding in monochorionic twin pregnancies in the prediction of twin-to-twin transfusion syndrome. In 83 monochorionic twin pregnancies ultrasound scans were carried out at 10-14, 15-17 and 19-21 weeks to investigate folding of the inter-twin membrane as an early sonographic feature of inter-twin discrepancy in amniotic fluid volume. There were 23 (28%) cases of membrane folding, which was first observed in one case at 10-14 weeks, in 21 cases at 15-17 weeks and in another case at 24 weeks. In 12 (52%) of the 23 cases the pregnancy progressed to severe twin-to-twin transfusion syndrome and 10 of these were treated by endoscopic laser coagulation of the placental vascular anastomoses. In the other 11 cases there was a moderate syndrome with large discrepancies in amniotic fluid volume and fetal size, persisting throughout pregnancy. In the severe group, five pregnancies resulted in live birth of both babies, three in live birth of one and intrauterine death of the other twin and in four cases there were no survivors. In the moderate group, all babies survived and the inter-twin disparity in birth weight was more than 20%. Similarly, all 60 pregnancies with no membrane folding resulted in live births. In all three groups there was an increase in inter-twin disparity in fetal size with gestation and the greatest inter-twin disparities were in those with moderate twin-to-twin transfusion syndrome from as early as the 10-14 week scan. These findings demonstrate that folding of the inter-twin membrane occurs in about one-quarter of monochorionic twins and in about half of these there is subsequent development of severe twin-to-twin transfusion syndrome.

Extraembryonic Membranes↗
PubMed1998

Detection of sex chromosome abnormalities by nuchal translucency screening at 10-14 weeks.

At 10-14 weeks of gestation more than 80 per cent of fetuses affected by trisomy 21 can be detected by a screening programme based on a combination of maternal age and fetal nuchal translucency thickness (NT). The screen positive group in such a programme also identifies fetuses with sex chromosome abnormalities. In this ongoing multicentre screening study, involving 61,972 singleton pregnancies, 53 cases of sex chromosome abnormalities were identified. The fetal NT was above the 95th centile in 87.9 per cent of the 33 cases with 45,XO, and in 40 per cent of the 20 cases with 47,XXX, 47,XYY or 47,XXX. However, it was estimated that at 12 weeks of gestation our population would contain 42 cases with 45,XO and 104 cases with 47,XXY, 47,XYY or 47,XXX. Since the rate of intra-uterine lethality, between 12 and 40 weeks of gestation, is about 65 per cent for 45,XO and four per cent for 47,XXY, 47,XYY or 47,XXX, the respective number of livebirths with these chromosomal abnormalities would have been 15 and 100, respectively, without prenatal diagnosis. Assuming that all intra-uterine deaths are from those with increased NT, screening for trisomy 21 by maternal age and fetal NT would have identified only 20 per cent of potential livebirths in the 45,XO group and nine per cent of those with 47,XXY, 47,XYY or 47,XXX.

Down Syndrome↗