Size Discordance Research Articles

90: Impact of birthweight discordance and of non-vertex presentation of the second twin on successful vaginal birth – The Esprit Trial

OBJECTIVE: To determine the impact of intratwin birthweight discordance and of non-vertex presentation of the second twin on successful vaginal delivery. STUDY DESIGN: The ESPRIT Trial is a national prospective population study of 642 consecutive twin pregnancies managed and delivered at 8 tertiary referral centers in one country. All pregnancies are followed using a uniform sonographic surveillance protocol. RESULTS: Vaginal or cesarean delivery (CD) was planned for 310 (48%) and 332 (52%) women, respectively. Birthweight discordance of 20% was documented in 12% (37/310) of patients who underwent a trial of labor. The sensitivity of ultrasound within 2 weeks of delivery for detection of this degree of discordance was 86%, specificity 61%. While the overall CD rate was 64% (411/642), intrapartum CD was needed in 29% (90/310) of cases where vaginal delivery was planned. Successful trial of labor did not correlate with advancing gestational age (logistic regression p-value 0.2409), vertex presentation of the 2nd twin (p-value 0.3252), nor with concordant size (regression p-value 0.2988). CONCLUSION: Neither size discordance nor non-vertex presentation of the 2nd twin is predictive of CD. When the larger twin is not presenting, successful vaginal delivery can still be anticipated in most cases.

Palatine tonsil size and its correlation with subjective tonsil size in patients with sleep-disordered breathing

Objective To investigate the correlation of subjective tonsil size with real palatine tonsil size and to compare the differences of each parameter according to subjective tonsil size and between children and adults. Study Design Prospective evaluation of subjective tonsil size (0-4+) and real palatine tonsil size, including tonsil height (TH), tonsil width (TW), tonsil thickness (TT), total tonsil volume (TTV), and embedded tonsil volume (ETV) within the tonsillar fossa. Setting Tertiary-care rhinologic clinic. Subjects and Methods We measured TH, TW, TT, TTV, and ETV in 277 children and 63 adults with sleep-disordered breathing (SDB). Results In both children and adults, subjective tonsil size was significantly correlated with TTV, TH, TW, and TT (correlation coefficients 0.199-0.427 for children and 0.462-0.551 for adults). In children, TTV increased in proportion to subjective tonsil size, but about 45 percent and 34 percent of tonsils markedly deviated from the mean value of their TTV in size 2 and 3 groups, respectively. In adults, TTV of subjective tonsil size 3 and 4 groups was significantly larger than that of size 1 and 2 groups. Conclusions Real palatine tonsil size correlated with subjective tonsil size in both children and adults with SDB. Although there is a statistical correlation in children between TTV and subjective tonsil size, there is significant discordance in size 2 and 3 groups, thus greatly limiting the value of subjective tonsil size assessment in the majority of children. However, adult subjective tonsil size may reflect real palatine tonsil size and may help predict it preoperatively.

Presentation of Nonfinal Results of Randomized Controlled Trials at Major Oncology Meetings

To assess the frequency, implications, and factors associated with reporting nonfinal analyses (NFAs) of randomized controlled trials (RCTs) as abstract publications. We identified 138 consecutive reports of RCTs testing systemic therapy for lymphoma, breast, colorectal, or non-small-cell lung cancer published in six major journals between 2000 and 2004. We then searched proceedings of seven major cancer meetings, 1990 to 2004, for abstracts related to these publications which presented efficacy results. Articles and abstracts were compared for discordance in sample size, median follow-up, results, and conclusions. Abstracts were evaluated for statements explicitly noting or implying that results were not final. Factors associated with discordance were assessed by uni- and multivariate analyses. We identified 303 related abstracts; 197 were eligible. In 86 abstracts (44%), results were stated or implied to be NFA; this was explicitly stated in 41 (21%). The NFAs included 12 where accrual was ongoing. Discordance with article was found in 124 abstracts (63%) and was more common with NFAs (67 of 86 [78%] v 57 of 111 [51%]; P = .0001). When compared with articles, authors' conclusions were substantively different in 17 abstracts (10%). Factors most associated with data discordance were lymphoma trial (odds ratio [OR], 3.8; 95% CI, 1.5 to 10.8), cooperative group trial (OR, 2.8; 95% CI, 1.4 to 5.6), and presentation of a NFA (OR, 2.9; 95% CI, 1.5 to 5.8). Meeting abstracts often include NFAs and are frequently discordant with subsequent article publication.

Discordance in body size, colour pattern, and advertisement call across genetically distinct populations in a Neotropical anuran (Dendropsophus ebraccatus)

Patterns of intraspecific geographic variation in morphology and behaviour, when examined in a phylogenetic context, can provide insight into the microevolutionary processes driving population divergence and ultimately speciation. In the present study, we quantified behavioural and phenotypic variation among populations from genetically divergent regions in the Central American treefrog, Dendropsophus ebraccatus. Our fine-scale population comparisons demonstrated regional divergence in body size, colour pattern frequencies, and male advertisement call. None of the characters covaried with phylogenetic history or geographic proximity among sampled populations, indicating the importance of highly localized selection pressures and genetic drift in shaping character divergence among isolated regions. The study underscores how multiple phenotypic characters can evolve independently across relatively small spatial scales. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 298‐313.

Superfœtation : à propos d’un cas et revue de la littérature

We report the case of a dichorionic-diamniotic pregnancy in which a discordance in the size of the fetuses was observed as early as the first trimester. This discordance in size was maintained over time and the two fetuses continued their respective growths. We suggest the very rare phenomenon of superfetation as a diagnosis because less than 10 cases are described in the literature. Even though a formal proof of the diagnosis is difficult to obtain, the elements described in this article rally in favor of this hypothesis. Superfetation is defined by the fertilization and the implantation of a second oocyte in a uterus already containing the product of a previous conception. After a description of the case, a review of the literature enables us to describe the frequency, the possible risk factors and the existing case reports on the subject. The rarity of this case justifies its publication for the information of clinicians.

Presentation of non-final results of randomized controlled trials (RCTs) at major oncology meetings

6550 Background: Presentation of non-final analyses of RCTs may be misleading and introduce bias to trial conduct. Here we evaluate presentation of non-final analyses of RCTs at seven major oncology meetings. Methods: We identified 138 consecutive article reports of systemic therapy RCTs for lymphoma, breast, colorectal, or non-small cell lung cancer published in six major journals 2000–2004. We then searched proceedings of seven major cancer meetings 1990–2004 for all related abstracts reporting primary efficacy outcomes. Study methodology and results were extracted from each article and abstract. Conference abstracts with suggestive language (eg, interim, results to date, current results) were recorded as implying that data were preliminary. Disagreement between article and abstract was defined as discordance in sample size, median follow-up, or results. Factors associated with disagreement were assessed by uni- and multivariate analyses. Strength of author conclusion was evaluated using a 7-point Likert scale. Results: We identified 303 abstracts of which 197 were eligible. Results were implied to be preliminary in 86 (44%) abstracts. Only 41 (21%) abstracts explicitly stated data were preliminary. Disagreement of data between article and conference abstract was found in 124/197 abstracts (63%) and was more common in abstracts implying data were preliminary (67/86 [78%] vs. 57/111 [51%]; p=.0001). By multivariate analysis, factors most associated with disagreement between article and abstract include implication that data were preliminary (OR 3, p=.0007), lymphoma trial (OR 4, p=.01) and trial not exclusively sponsored by industry (OR 3, p=.04). Author conclusion to adopt experimental regimen differed between abstract and article in 23 (14%) cases. No differences in conclusion to adopt were detected between RCTs showing disagreement and those showing no disagreement of data. Conclusions: The majority of RCT abstracts presented at major oncology conferences include important items of data that are discordant with published articles, suggesting that reporting of non-final analyses is common. While discordance is most frequent in abstracts that indicate analyses are preliminary, it is also common in abstracts that do not indicate preliminary reporting. No significant financial relationships to disclose.

Stage I twin–twin transfusion syndrome: rates of progression and regression in relation to outcome

Twin-twin transfusion syndrome (TTTS) results in high rates of perinatal mortality and neurological morbidity. Fetoscopic laser ablation of placental anastomoses is now established as the treatment of choice for advanced disease. However, there remains controversy about its use in early-stage TTTS, in which laser-related fetal losses need to be balanced against relatively favorable outcomes with more conservative approaches. We investigated rates of progression and regression in Stage I TTTS and determined factors influencing the course of the disease. We undertook a retrospective observational study of all TTTS cases referred to our tertiary referral fetal medicine service from 2000 to 2006. In patients presenting with Stage I TTTS, the following variables were evaluated for their ability to predict the course and progression of the disease: gestational age (GA) at presentation, amniotic fluid index, recipient and donor deepest vertical pool, presence of artery-artery anastomoses, small-sized bladder compared to normal donor bladder and fetal size discordance. Study end-points were disease regression or progression, and neonatal survival at 28 days. Among 132 consecutive cases of TTTS, 46 women presented with Stage I disease. In the majority (69.6%), disease remained stable (28.3%) or regressed (41.3%). Of cases that progressed, 79% did so within 2 weeks and 93% progressed to at least Stage III. No factor was significantly linked with progression or regression, although there was a trend towards the absence of an artery-artery anastomosis (P = 0.10) and the presence of a small rather than normal donor bladder (P = 0.10) influencing progression, and later GA at presentation (P = 0.07) influencing regression. At least one infant survived in 83% of cases and there was double survival in 59%. Perinatal outcome was significantly better in cases that regressed (the rates of at least one survivor and double survival being 89% and 89%, respectively) or remained Stage I (77% and 61%, respectively), compared with those cases that progressed (79% and 14%, respectively). Treatment with amnioreduction at first presentation did not influence progression or regression. This study demonstrates that a high percentage of Stage I TTTS cases regress or remain early stage. Identification of factors predicting progression would facilitate the selection of patients for definitive therapy, while avoiding treatment-related morbidities in mild or transient disease.

Clinical consequences of first-trimester growth discordance in twins

Objectives: To evaluate the clinical consequences of size discordance in the first-trimester of pregnancy in twins. Study design: This study was performed in a university tertiary referral centre. Nineteen pairs of twins identified as discordant were compared with 41 concordant twins. The rates of intrauterine growth restriction (IUGR), congenital malformations, and growth discordance in late pregnancy and at delivery were compared using chi-squared test and Fisher's exact test. Results: There was not a significant difference in the rate of congenital malformations between the studied groups. The rates of IUGR and fetal growth discordance in late pregnancy were significantly higher in the first-trimester discordant group (57.2 and 35.7%, respectively) than in the control group (24.4 and 7.3%; P = 0.03 and 0.02, respectively). Conclusions: First-trimester growth discordant twins have an increased risk of IUGR and growth discordance in late pregnancy, and therefore they are a high-risk subgroup among multiple pregnancies.

OC224: First trimester intertwin size discordance

What is the clinical significance of first trimester discordance in the crown-rump lengths (CRL) in twin pregnancies. During a 40 months period, interfetal age differences were analyzed in 205 consecutive twin pregnancies by CRL measurements between 21–79 mm. Eight patients were lost for follow-up and hence excluded. Discordant fetal size was defined as a difference in CRL equal to 5 or more days. Differences in chorionicity, pregnancy and fetal loss rates, mean gestational ages at birth, mean birth weights and congenital malformations were analyzed and compared with concordant pregnancies. Statistical analysis was carried out by Fisher exact or c2 tests. Fetal size was concordant in 179/197 twin pregnancies (91%) (group A) and discordant in 18/197 twin pregnancies (9%) (group B). Significantly more monochorionic pregnancies than dichorionic pregnancies showed a first trimester discordant twin size (9/35 versus 9/162: p < 0.001). Compared with group A, group B revealed significantly more intentional pregnancy (4/18 versus 12/179: p = 0.0216) and fetal (10/36 versus 28/358 p = 0.0001) losses and more congenital malformations (9/36 versus 16/358: p < 0.0001). The risk of spontaneous pregnancy loss (1/18 versus 4/179: p = 0.29) and fetal demise (2/36 versus 9/358: p = 0.4) were not significantly different in both groups. Mean birth weights and mean gestational ages at the time of delivery in both groups were comparable. Discordant fetal size is more frequently found in monochorionic twin pregnancies. The presence of a CRL discordance is related with an increased risk for congenital anomalies. However abnormalities excluded, there is no further negative effect on pregnancy outcome.

Normal and abnormal growth of multiples

Growth curves of twins and triplets do not support a growth restriction patterns seen in singletons. At the same time that individual members of a twin or a triplet set may be smaller than singletons of the same gestational age, only a minority are indeed SGA by singleton standards. When comparing the entire ‘fetal mass’ of a multiple pregnancy to that of singletons, multiple gestations are in fact growth promoted, and their individual smaller size are better described as growth adaptation . Data from large twin and triplet series suggest that significant birth weight discordance result from the inability of the uterine milieu to equally nurture twins. In order to promote maturity – gestational age – mild compensation in the form of size discordance begins after mid-gestation. When the uterine environment competently nurtures multiples, total birth weight increases and discordance decreases. Failed adaptation, however, may result in significant growth discordance and restriction.

Is birthweight associated with thyroid autoimmunity? A study in twins.

Although extensive studies have suggested that an individual's predisposition to develop autoantibodies to thyroid peroxidase (TPOAb) and thyroglobulin (TgAb) has a genetic component, a recent report has suggested that growth restriction during fetal life may also contribute. We have therefore measured TPOAb and TgAb in a population-based study of twins (44 monozygous and 91 dizygous) born between 1950 and 1955 who were identified through a registry of birth records in Birmingham, United Kingdom. TPOAb and TgAb were measured by a highly sensitive immunoprecipitation assay in which 0.01 U/mL and 0.1 U/mL, respectively, were detectable. TPOAb were found in 49 of 156 (31%) of women and 7 of 116 (6%) of men with similar values for TgAb (31% and 9%, respectively). Of 28 monozygous pairs, 10 were concordant for TgAb and 7 discordant giving a probandwise concordance rate of 74%. Concordance rates for TPOAb were similar (64%) and were higher than concordance rates in dizygous twins. Monozygous twins had a higher prevalence of TgAb than dizygous twins (30% vs. 17%, p = 0.01). In addition, we found that where there was discordance in birth size within monozygous twin pairs, the smaller twin had a higher prevalence of TPOAb (p = 0.01). Our results suggest that both heritable and early environmental components contribute to the susceptibility to thyroid autoimmunity.

The Foetal Origins of Adult Disease: Interpreting the Evidence From Twin Studies

AbstractTwin studies have a contribution to make to the debate concerning the foetal origins of adult disease. Twins are growth retarded compared to singletons and experience post-natal catch-up growth. However, there is no evidence that twins are at increased risk of cardiovascular disease. Studying whether discordance in size at birth within monozygotic twin pairs is predictive of discordance in later life disease should help resolve whether the association between size at birth and later disease is due to common genetic factors. Results from studies of blood pressure in childhood and adult life looking at these within twin effects are far from conclusive. There are, however, methodological problems in the interpretation of these results, not least of which is the relatively small numbers of twin pairs studied. Studies exploring the effect of zygosity and chorion type on later disease provide may provide a useful extension of the research agenda. In summary, twin studies to date have raised more questions about the foetal origins hypothesis than they have resolved.

First-trimester embryo size discordance: a predictor of premature birth following multifetal pregnancy reduction

Objective: We have previously reported a correlation between the starting number of embryos for multifetal pregnancy reduction (MFPR) and discordance in size during the first trimester. Here we evaluated the correlation between the degree of discordance and length of gestation in the remaining fetuses. Design: Observational clinical series. Setting: Academic medical center with a single physician who performs a large number of MFPRs. Patient(s): Analysis of 252 consecutive MFPRs from a 2.5-year period (1996–1998). Intervention(s): MFPR for patients with multifetal pregnancies. Main Outcome Measure(s): We evaluated the correlation between the degree of discordance in embryo size, as measured by the greatest difference in crown-rump length (CRL) (Δ max), and the length of gestation. Result(s): Embryo size discordance was related to length of gestation of the remaining fetuses after MFPR. Of 72 patients with a Δ max >5 mm, the rate of severe premature birth (delivery at <28 weeks’ gestation) was 9.7%, compared with 1.7% for patients with a Δ max <5 mm ( P<.01). Of patients with severe premature birth, 70% had Δ max >5 mm, compared with less than 30% in patients who delivered after 28 weeks ( P<.05). Conclusion(s): Variations in embryo growth patterns in multifetal pregnancies may be observed even in the first trimester, which may be predictive of late pregnancy outcomes. With a Δ max ≥5 mm, there is a significant increase in the risk of severe premature birth (delivery at <28 weeks).

Staging of Twin-Twin Transfusion Syndrome

The purpose of this study was to evaluate the prognostic value of sonographic and clinical parameters to develop a staging classification of twin-twin transfusion syndrome (TTTS). Severe TTTS was defined as the presence of polyhydramnios (maximum vertical pocket of > or = 8 cm) and oligohydramnios (maximum vertical pocket of < or = 2 cm). Nonvisualization of the bladder in the donor twin (-BDT) and absence of presence of hydrops was also noted. The middle cerebral artery, umbilical artery, ductus venosus, and umbilical vein in both fetuses were assessed with pulsed Doppler. Critically abnormal Doppler studies (CADs) were defined as absent/reverse end-diastolic velocity in the umbilical artery, reverse flow in the ductus venosus, or pulsatile flow in the umbilical vein. TTTS was staged as follows: stage I, BDT still visible; stage II, BDT no longer visible, no CADs; stage III, CADs; stage IV, hydrops; stage V, demise of one or both twins. Laser photocoagulation of communicating vessels (LPCV) or umbilical cord ligation was performed depending on the severity of the condition. The study was approved by the Institutional Review Board of St. Joseph's Hospital in Tampa and by the Fetal Therapy Board at Hutzel Hospital, Detroit, and all patients gave informed consent. A total of 80 of 108 referred patients met criteria for surgery, but only 65 were treated surgically: 48 with LPCV and 17 with umbilical cord ligation. Complete Doppler data were obtainable in 41 of 48 LPCV patients. Survival rates by stage for one or two fetuses were statistically different (chi-squared analysis = 12.9, df = 6, p = 0.044). Neither percent size discordance nor gestational age at diagnosis were predictive of outcome. Staging of TTTS using the proposed criteria has prognostic significance. This staging system may allow comparison of outcome data of TTTS with different treatment modalities.

Spontaneous superfetation diagnosed in the first trimester with successful outcome.

We report a twin pregnancy in which a 4-week discordance in size between the fetuses was identified in the first trimester. The discordance was maintained throughout the pregnancy, which was otherwise uneventful and resulted in the delivery of a live girl and boy.

Evaluation of fetal lung maturity in diamniotic twins

Objective: This study was undertaken to evaluate the correspondence in fetal lung development between diamniotic twins. Study Design: Lecithin/sphingomyelin ratios were determined for amniotic fluid specimens collected from each sac in 58 diamniotic twin pregnancies. Results: Overall, the lecithin/sphingomyelin ratios of twin A and twin B and those of the larger and smaller twins of each pair were closely correlated ( r ≥ 0.83, P < .001). When stratified by gestational age, however, the percentage disparity in lecithin/sphingomyelin ratios between members of twin pairs was significantly greater at ≤32 weeks’ gestation (25%) than at >32 weeks’ gestation (15%, P = .027). An analysis of the lecithin/sphingomyelin ratios of twins with a large lecithin/sphingomyelin ratio disparity (≥20%) suggested that this disparity was a result of 1 twin having a lecithin/sphingomyelin ratio that was advanced for gestational age with respect to that of the co-twin. Disparities in lecithin/sphingomyelin ratio were not significantly affected by fetal sex or by discordance in size between the twins. Conclusion: At relatively early stages of diamniotic twin gestation (≤32 weeks’ gestation), lecithin/sphingomyelin ratios should be obtained for both amniotic sacs to ensure accurate assessment of fetal lung maturity in both twins. (Am J Obstet Gynecol 1999;180:1438-41.)

Thoracic Outlet Vascular Injuries

Management of vascular injuries at the thoracic outlet and neck continues to be a major problem to the trauma surgeon. Of 47 patients treated over an eighteen-year period, 45 were due to penetrating injuries (41 gunshot [87.2%], 4 stab wounds [8.5%]). In 16 patients shock was present at the time of admission. Five patients were operated on in comatose condition. In 37 patients immediate, and in 10 cases delayed, operation was performed. In 13 patients with arterial injuries, end-to-end anastomosis; in 24, saphenous vein graft; in 6, synthetic graft; in 2, lateral suture; and in 2, ligation were performed. Three subclavian arterial injuries repaired by saphenous vein graft occluded owing to thrombosis, requiring synthetic graft replacement. In 3 axillary arterial injuries, ligation was performed following the operation because of infection. One of these patients underwent amputation. Only 3 of 14 brachial plexus injuries (BPI) were primarily repaired. In only 1 of 3 repaired patients did complete function return. Overall mortality was 5 including 3 comatose patients with carotid injuries and 2 with axillary arterial injuries. In conclusion: (1) Subclavian and axillary artrial injuries may be overlooked by physical examination in the absence of critical ischemia. (2) We recommend ligation instead of revascularization in comatose carotid injury cases. (3) Synthetic grafts may be used, in cases of size discordance or in unstable patients, to end the operation as soon as possible. (4) In associated venous injuries, repair should be preferred to ligation. (5) In the presence of BPI due to gunshot wounds the results are not good in spite of nerve repair, and serious sequelae may remain.

Recovery of impaired left ventricular function in patients with acute myocardial infarction is predicted by the discordance in defect size on 123I-BMIPP and 201Tl SPET images.

A discrepancy between myocardial perfusion defect and wall motion abnormalities is frequently found early after coronary reperfusion in patients with acute myocardial infarction. The purpose of this study was to assess recovery of impaired left ventricular function by reference to the discordance in defect size between myocardial fatty acid uptake and myocardial perfusion using combined single-photon emission tomographic (SPET) imaging early after coronary perfusion therapy. In 37 patients with acute myocardial infarction, iodine-123 15-(p-iodophenyl)-3(R, S)-methylpentadecanoic acid (BMIPP) and thallium-201 SPET scans were performed early after coronary reperfusion. A severity score was determined from the extent of the imaging defect with each tracer. Left ventricular wall motion score (WMS) and ejection fraction (EF) were obtained at admission and at 4 weeks after the onset of infarction. In 32 of the 37 patients, discordance in defect sizes delineated with the two SPET studies was found during the acute stage. The severity score for BMIPP was larger than that for 201Tl during the acute stage (7. 7+/-2.4 vs 4.4+/-2.5, P <0.001). There was a fair correlation between the severity score for BMIPP and WMS (r=0.82, P <0.0001), but a poor correlation between that for 201Tl and WMS. The extent of discordance in severity scores between BMIPP and 201Tl during the acute stage correlated well with the extent of the improvement in WMS (r=0.86, P <0.0001) and that of EF (r=0.85, P <0.0001). We conclude that the discordance in defect size on BMIPP and 201Tl SPET images during the acute stage of infarction is an early predictor of the viability of the myocardium at risk of infarction.

Dual Radionuclide Study of Acute Myocardial Infarction

We evaluated dual imaging with thalium-201 (201TI) and technetium-99m (99mTc) pyrophosphate in 80 patients with documented acute myocardial infarction (55 transmural, 25 nontransmural infarction). Color-coded isocount display of 201TI images was essential for interpretation in 16 patients. Combined 201 TI and 99mTc-pyrophosphate imaging for infarct detection was 100% sensitive; however, either was falsely negative in 12 of 80 patients. False-negative individual 201TI or 99mTc-pyrophosphate infarct images were most common in patients with small infacts or left ventricular hypertrophy. Thallium-201 images correctly localized the site of acute transmural infarction in all 51 patients with a positive image, while 99mTc-pyrophosphate localized the site of infarction in 49 of 53 with an abnormal image. Comparison of the size of the imaged infarct region revealed size discordance in 25 of 49 patinets, with 99mTc-pyrophosphate larger in 21 of 49 and 201TI larger in only four of 49. Thus dual radionuclide imaging provides definition of the presence and location of acute myocardial infarction.