Placental volume in twin and triplet pregnancies measured by three-dimensional ultrasound at 11 + 0 to 13 + 6 weeks of gestation.
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OBJECTIVE: To compare the placental volume at 11 + 0 to 13 + 6 weeks' gestation between singleton and multiple pregnancies and to examine the possible effect of chorionicity on placental volume. METHODS: The placental volume was measured by three-dimensional (3D) ultrasound using the Virtual Organ Computer-aided AnaLysis (VOCAL) technique in 290 consecutive twin and 37 triplet pregnancies at 11 + 0 to 13 + 6 weeks of gestation. For the comparison of twin, triplet and singleton placental volumes each measurement was expressed as a multiple of the median (MoM) for singletons, previously established from the study of 417 normal fetuses at 11 + 0 to 13 + 6 weeks of gestation. RESULTS: Median twin and triplet placental volumes were 1.66 and 2.28 MoM for singletons, respectively. In twins the placental volumes increased significantly with gestation from a median of 83.6 mL (5th and 95th centiles: 56.0 mL and 124.9 mL) at 11 + 0 weeks to 149.3 mL (5th and 95th centiles: 100.0 mL and 223.1 mL) at 13 + 6 weeks. The median MoM in monochorionic twins was not significantly different from that in dichorionic twins with fused placentas or dichorionic twins with separate placentas. In triplets the placental volumes increased significantly with gestation from a median of 114.9 mL (5th and 95th centiles: 77.6 mL and 170.1 mL) at 11 weeks to 217.9 mL (5th and 95th centiles: 147.2 mL and 322.5 mL) at 13 + 6 weeks. There were no significant differences in total placental volume between monochorionic and dichorionic triplets, monochorionic and trichorionic triplets, or dichorionic and trichorionic triplets. CONCLUSIONS: Placental volume in multiple pregnancies does not depend on chorionicity, and the rate of placental growth between 11 and 13 + 6 weeks is not significantly different between singletons, twins and triplets. Moreover, for a given gestational age the placental volume corresponding to each fetus in twins and triplets is 83% and 76%, respectively, of the placental volume in singletons. (+info)
Only six cases of spontaneous, unilateral, triplet ectopic gestations have previously been reported. We now present a seventh case. The patient's prior obstetrical history was significant for a term stillbirth and a term cesarean section for breech. Quantitative betahCG was normal for gestational age; however, the increased trophoblastic mass of an inappropriately implanted multiple gestation may produce sufficient betahCG to mimic an intrauterine singleton gestation. Resolution was achieved via salpingostomy. This case is significant for being spontaneously conceived and not the result of assisted reproductive technologies. Furthermore, this case supports an association between prior cesarean section and ectopic gestation. (+info)
Relative contribution of genetic and nongenetic modifiers to intestinal obstruction in cystic fibrosis.
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BACKGROUND & AIMS: Neonatal intestinal obstruction (meconium ileus [MI]) occurs in 15% of patients with cystic fibrosis (CF). Our aim was to determine the relative contribution of genetic and nongenetic modifiers to the development of this major complication of CF. METHODS: A total of 65 monozygous twin pairs, 23 dizygous twin/triplet sets, and 349 sets of siblings with CF were analyzed for MI status, significant covariates, and genome-wide linkage. RESULTS: Specific mutations in the CF transmembrane conductance regulator (CFTR), the gene responsible for CF, correlated with MI, indicating a role for CFTR genotype. Monozygous twins showed substantially greater concordance for MI than dizygous twins and siblings (P = 1 x 10(-5)), showing that modifier genes independent of CFTR contribute substantially to this trait. Regression analysis revealed that MI was correlated with distal intestinal obstruction syndrome (P = 8 x 10(-4)). Unlike MI, concordance analysis indicated that the risk for development of distal intestinal obstruction syndrome in CF patients is caused primarily by nongenetic factors. Regions of suggestive linkage (logarithm of the odds of linkage >2.0) for modifier genes that cause MI (chromosomes 4q35.1, 8p23.1, and 11q25) or protect from MI (chromosomes 20p11.22 and 21q22.3) were identified by genome-wide analyses. These analyses did not support the existence of a major modifier gene on chromosome 19 in a region previously linked to MI. CONCLUSIONS: The CFTR gene along with 2 or more modifier genes are the major determinants of intestinal obstruction in newborn CF patients, whereas intestinal obstruction in older CF patients is caused primarily by nongenetic factors. (+info)
The changing risk of infant mortality by gestation, plurality, and race: 1989-1991 versus 1999-2001.
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OBJECTIVE: Our aim was to quantify contemporary infant mortality risks and to evaluate the change by plurality, gestation, and race during the most recent decade. PATIENTS AND METHODS: The study population included live births of 20 to 43 weeks' gestation from the 1989-1991 and 1999-2001 US Birth Cohort Linked Birth/Infant Death Data Sets, including 11,317,895 and 11,181,095 live births and 89,823 and 67,129 infant deaths, respectively. Adjusted odds ratios and 95% confidence intervals were calculated to evaluate the change in risk by plurality and gestation and to compare the change with that for singletons. RESULTS: Overall, the infant mortality risk decreased significantly for singletons, twins, and triplets but nonsignificantly for quadruplets and quintuplets. Compared with singletons, significantly greater reductions were experienced by twins overall and at <37 weeks and triplets at <29 weeks. The largest reduction was for triplets at 20 to 24 weeks and for quadruplets and quintuplets at 25 to 28 weeks. For white infants, significant reductions were achieved overall for singletons, twins, and triplets and at every gestation. For black infants, significant reductions occurred for singletons overall and at every gestation, for twins at <37 weeks, and for triplets at 25 to 28 weeks. Compared with white infants, black infants had significantly lower risks before and higher risks after 33 weeks, although between 1989-1991 and 1999-2001 this survival advantage at earlier ages diminished, and the risk at later gestations increased. CONCLUSIONS: The improvements in survival were greater for multiples versus singletons and for white versus black infants. Within each plurality, at each gestation the racial disparity in mortality has widened. (+info)
Contemporary risks of maternal morbidity and adverse outcomes with increasing maternal age and plurality.
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OBJECTIVE: To evaluate the risks of pregnancy complications and adverse outcomes associated with increasing maternal age and higher plurality. DESIGN: Population-based, historic cohort study. SETTING: US birth certificates and infant death certificates. PATIENT(S): Live births of > or =20 weeks gestation between 1995-2000: 22,991,306 singleton, 316,696 twin, and 12,193 triplet pregnancies. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Pregnancy-associated hypertension, incompetent cervix, tocolysis, premature rupture of membranes, excessive bleeding at delivery, delivery <29 weeks, and infant death. RESULT(S): Compared to singletons, the risks for all adverse outcomes among multiple pregnancies were significantly elevated, and were highest for tocolysis, delivery <29 weeks, and infant mortality. Within pluralities, increasing maternal age was associated with significantly higher risks of pregnancy-associated hypertension, excessive bleeding, and incompetent cervix, but for twin and triplet pregnancies, significantly lower risks for tocolysis (ages > or =40, singleton adjusted odds ratio [AOR] 0.97, twin AOR 0.67, triplet AOR 0.72), delivery <29 weeks (ages > or =40, singleton AOR 1.55, twin AOR 0.72, triplet AOR 0.52), and infant mortality (ages > or =40, singleton AOR 1.34, twin AOR 0.71, triplet AOR 0.42). CONCLUSION(S): Older maternal age and higher plurality are each associated with increasing risks for many pregnancy complications, but with significantly lower risks of tocolysis, early preterm birth, and infant mortality. (+info)
An exact nonparametric method for inferring mosaic structure in sequence triplets.
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Statistical tests for detecting mosaic structure or recombination among nucleotide sequences usually rely on identifying a pattern or a signal that would be unlikely to appear under clonal reproduction. Dozens of such tests have been described, but many are hampered by long running times, confounding of selection and recombination, and/or inability to isolate the mosaic-producing event. We introduce a test that is exact, nonparametric, rapidly computable, free of the infinite-sites assumption, able to distinguish between recombination and variation in mutation/fixation rates, and able to identify the breakpoints and sequences involved in the mosaic-producing event. Our test considers three sequences at a time: two parent sequences that may have recombined, with one or two breakpoints, to form the third sequence (the child sequence). Excess similarity of the child sequence to a candidate recombinant of the parents is a sign of recombination; we take the maximum value of this excess similarity as our test statistic Delta(m,n,b). We present a method for rapidly calculating the distribution of Delta(m,n,b) and demonstrate that it has comparable power to and a much improved running time over previous methods, especially in detecting recombination in large data sets. (+info)
Genetic and environmental bases of childhood antisocial behavior: a multi-informant twin study.
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Genetic and environmental influences on childhood antisocial and aggressive behavior (ASB) during childhood were examined in 9- to 10-year-old twins, using a multi-informant approach. The sample (605 families of twins or triplets) was socioeconomically and ethnically diverse, representative of the culturally diverse urban population in Southern California. Measures of ASB included symptom counts for conduct disorder, ratings of aggression, delinquency, and psychopathic traits obtained through child self-reports, teacher, and caregiver ratings. Multivariate analysis revealed a common ASB factor across informants that was strongly heritable (heritability was .96), highlighting the importance of a broad, general measure obtained from multiple sources as a plausible construct for future investigations of specific genetic mechanisms in ASB. The best fitting multivariate model required informant-specific genetic, environmental, and rater effects for variation in observed ASB measures. The results suggest that parents, children, and teachers have only a partly "shared view" and that the additional factors that influence the "rater-specific" view of the child's antisocial behavior vary for different informants. This is the first study to demonstrate strong heritable effects on ASB in ethnically and economically diverse samples. (+info)
Impact of a multiple, IVF birth on post-partum mental health: a composite analysis.
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BACKGROUND: This study explored the impact of a multiple IVF birth on maternal mental health in the early post-partum period. METHODS: A prospective study of 207 women who had conceived following IVF treatment and followed up at 6 weeks post-partum. Mothers rated their mood using the Edinburgh postnatal depression scale (EPDS) and their baby's behaviour using the Unsettled and Irregular Behaviour scale. Mothers' emotional well-being was explored using theme analysis of semi-structured telephone interviews. RESULTS: Of the 175 (84.5%) followed up post-partum, 56 (32%) had a multiple birth (7 triplets, 49 twins). Nearly 16% of mothers in the multiple group scored>12 on the EPDS indicating clinically significant symptoms, which represented a 3-fold increased risk compared to mothers of singletons (Odds ratio=3.4, Confidence Interval=1.011-11.618, P=0.048). Unsettled and irregular infant behaviour was another independent risk factor. Qualitative analysis of interviews identified 12 themes. Mothers of multiples were more likely to express negative themes including 'tiredness' (P<0.01), 'feelings of stress/depression' (P<0.05) and 'questioning parenthood' (P<0.05). Mothers of singletons were more likely to be 'feeling wonderful', reflecting their delight in parenthood (P<0.05). CONCLUSIONS: Mothers of multiples are at increased risk of poorer emotional well-being. Clinicians should focus on the psychological benefits of a singleton birth. (+info)