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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↗
PubMed2006

The relationship between birthweight discordance and perinatal mortality of one of the twins in a twin pair.

This study aimed to evaluate the prevalence of birthweight discordance among twins, to determine the risk cut-off point for birthweight discordance, and to clarify whether perinatal deaths are aggravated by birthweight discordance or by low birthweight itself. A population-based analysis of all twins born between 1995 and 1999 in Japan was conducted using data collected from national birth, death and stillbirth certificates. Birthweight discordance was determined as: higher birthweight minus lower birthweight divided by higher birthweight multiplied by 100. Among twins with a birthweight discordance of more than 15%, the fetal and perinatal mortality rate was higher than that of twins with a discordance of less than 15%. Ninety per cent of the relative cumulative frequency of twin live-births were within 25% of the birthweight discordance. Logistic regression analysis showed that the stillbirth of at least one of the twins is associated with the birthweight of the larger twin and birthweight discordance. It also showed that the stillbirth of both twins in the twin pair is associated with the birth-weight of larger twins and the gestational weeks. It was clarified that birthweight discordance was associated with the stillbirth of only one twin in the twin pair, and the stillbirth of both twins in the twin pair was associated with low birthweight itself.

Birth Weight↗
PubMedDate not supplied

"Pseudo" twin-to-twin transfusion syndrome and fetal outcome.

OBJECTIVE: To assess the fetal outcome, in a tertiary center, in pregnancies with suspected twin-to-twin transfusion syndrome (TTTS) not confirmed using ultrasonographic examination, diagnosis of pathology, or both. STUDY DESIGN: Forty-four pregnancies with suspected TTTS were followed longitudinally using ultrasonographic examination until delivery. The minimal criteria for the diagnosis of TTTS were: (1) suspicion of monochorionicity gleaned from ultrasound examination (to be confirmed at birth); (2) presence of polyhydramnios in one gestational sac (either assessed subjectively--or, finding that the largest vertical pocket of amniotic fluid was >8 cm in diameter before 20 weeks' gestation and >10 cm in diameter thereafter); and (3) presence of oligohydramnios in the other gestational sac (finding either that there was a "stuck" twin complication or that the largest vertical pocket of amniotic fluid was <1 cm in diameter). When one of the above criteria was not present, the pregnancy was defined as "pseudo" TTTS. Fetal outcome in "pseudo" TTTS was analyzed according to the relative size of the neonate (large or small) and whether the cord insertion was normal or velamentous. RESULTS: There were 18 cases of "pseudo" TTTS. No treatment in utero was necessary in any of the 18 pregnancies. The mean gestational age was 21.9 +/- 3.7 (1 SD) weeks at diagnosis and 33.0 +/- 3.0 weeks at delivery. The average weight discrepancy between the twins at birth was 34.3 +/- 14.8%. There were three fetal demises of the small twin and one neonatal demise of the large twin (p > 0.05). Large twins developed respiratory distress syndrome (RDS) more often than small twins (p < 0.05). Five percent of the large twins and 50% of the small twins had a velamentous insertion of the cord (p < 0.05). CONCLUSION: In pregnancies complicated by "pseudo" TTTS our data indicate that: (1) small twins have abnormal cord insertion more frequently than large twins, (2) large twins develop RDS more frequently than small twins. Our data suggest that the perinatal mortality in these pregnancies appears to be lower than that reported for the classical TTTS.

Amniocentesis↗
PubMed2001

Is the genetic liability in multifactorial disorders higher in concordant than discordant monozygotic twin pairs? A population-based family twin study of migraine without aura.

Migraine without aura (MO) is a multifactorial disorder. Expression of a disorder with multifactorial inheritance depends on the genetic liability and on environmental factors. A high liability is reflected by a high frequency of affected relatives. We have previously shown that monozygotic (MZ) twin pairs have a significant higher concordance of MO than dizygotic twin pairs. The incomplete concordance among MZ twin pairs may be due to a lower genetic liability among discordant than concordant MZ twin pairs. The present study analysed the genetic liability in MZ twin pairs concordant and discordant for MO by the population-relative risk of MO among parents and siblings. The twin pairs were from the population-based Danish Twin Register. First-degree relatives of 29 concordant and 34 discordant MZ twin pairs were blindly telephone interviewed by a physician. The participation rate of the eligible first-degree relatives was 96%. The population-relative risk of MO among parents and siblings was 2.73 (2.39-3.06) in concordant and 2.37 (2.03-2.71) in discordant MZ twin pairs. The relative risk of MO was significantly higher in female first-degree relatives of concordant than of discordant MZ male and female twin pairs. An opposite effect was observed in male first-degree relatives, although this was not significant for male first-degree relatives of female MZ twin pairs. The present study found no statistically significant difference in genetic liability to MO among concordant and discordant MZ twin pairs. However, a difference in genetic liability among MZ and DZ twin pairs is anticipated to be small. Thus, it may be possible to show the effect in a larger study population or by investigating a more frequent trait than MO.

Adolescent↗
PubMed1998

Lower risks of adverse outcome in twins conceived by artificial reproductive techniques compared with spontaneously conceived twins.

The outcomes of twins conceived by 136 women after medical assistance (MA) such as ovulation induction with or without assisted reproductive techniques, and twins conceived spontaneously (SP) by 72 women were compared. All 208 women were monitored from < 20 weeks gestation; they all delivered at > or = 24 weeks gestation. The chorionicity of the placenta was diagnosed antenatally and confirmed after delivery. There were 10 perinatal deaths; the physical and neurological status of the remaining 406 infants was assessed at 1 year of corrected age. There were no differences in gestational age at birth, the birth weights of the larger and smaller twins, the birth weight discordance, or the incidence of life-threatening major malformations between groups. Adverse infant outcomes, such as death, cerebral palsy and mental retardation occurred in nine (3.3%) of 272 MA twins compared with 12 (8.3%) of 144 SP twins (P < 0.05). The placenta was monochorionic in only three (2.2%) of 136 MA twin pregnancies compared with 41 (57%) of 72 SP twin pregnancies (P < 0.001). Of the 21 infants with adverse outcomes, nine had monochorionic placentas. Thus, the risk of an adverse outcome was 2.8-fold higher (95% confidence interval (CI) 1.2-6.4) in monochorionic twins than in dichorionic twins (10 versus 3.7%; P < 0.05). There was no difference in the incidence of adverse infant outcomes between SP (4.8%) and MA (3.4%) twins with dichorionic placentas. These findings suggest that ovulation induction in itself was not associated with an adverse outcome of twin pregnancies. The lower frequency of monochorionic placentas in MA twins may have been responsible for the lower risk of an adverse outcome in MA twins.

Birth Weight↗
PubMed1988

Psychic vulnerability as a sequel to perinatal morbidity. A longitudinal twin study with special reference to psychiatric morbidity and inter-twin dependency.

In this follow-up study 497 twins from 335 twin deliveries were examined between the ages of 12-20 years to ascertain late effects of perinatal complications and mild neurological abnormalities on mental health, by means of questionnaires filled in by the parents and by the twins themselves. One third of the twins had not suffered from any perinatal complications, while one third had been small for gestational age, one third had been born prematurely and one third had suffered from respiratory disorders. Neonatal hypoglycaemia had been found in 22% and hyperbilirubinaemia in 7% of the twins. Perinatal complications had occurred in almost all those twins who later underwent inpatient psychiatric treatment. Most perinatal problems were reflected in the twin's dependency on his co-twin, showing in particular a cumulative effect when occurring simultaneously. Those twins who are currently more dependent learned to walk and speak later than the non-dependent ones, and their EEG background activity of ten years ago, at the age of 2-10 years, was more abnormal than that of the non-dependent ones, indicating brain organic, i.e. probably perceptual, factors enhancing the development of inter-twin dependency. The dependent twins were more submissive and had the most frequent feelings of inferiority. The neurological, psychological and family interactional factors that cause a twin to distrust himself and depend on his co-twin are also discussed in this study.

Dependency, Psychological↗
PubMed1998

Twin studies of adult psychiatric and substance dependence disorders: are they biased by differences in the environmental experiences of monozygotic and dizygotic twins in childhood and adolescence?

BACKGROUND: Twin studies have long been used to disentangle the role of genetic and environmental factors in the aetiology of psychiatric disorders. However, the validity of the twin method depends on the equal environment assumption--that monozygotic (MZ) and dizygotic (DZ) twins are equally correlated in their exposure to environmental factors of aetiological importance for the disorder under study. METHODS: Both members of 822 female-female twin pairs from a population-based registry previously assessed for a range of psychiatric and substance use disorders were asked 12 questions assessing the similarity of their environmental experiences in childhood and adolescence. We examined whether the similarity of environmental experiences predicted concordance for psychiatric and substance abuse disorders by both a 'pair-wise' and 'individual' method utilizing logistic regression. We also examined smoking initiation, where prior evidence suggested a role for adolescent social environment. RESULTS: Three factors were derived from these items: 'Childhood treatment', 'Co-socialization' and 'Similitude'. Members of twin pairs agreed substantially in their recollections of these experiences. Compared with DZ twins, MZ twins reported comparable resemblance in their childhood treatment, but socialized together more frequently and reported that parents, teachers and friends more commonly emphasized their similarities. None of these three factors significantly predicted twin resemblance for major depression, generalized anxiety disorder, panic disorder, phobias, nicotine dependence or alcohol dependence. However, co-socialization significantly predicted twin resemblance for smoking initiation and perhaps for bulimia. CONCLUSION: Differential environmental experiences of MZ and DZ twins in childhood and adolescence are unlikely to represent a substantial bias in twin studies of most major psychiatric and substance dependence disorders but may influence twin similarity for the initiation of substance use.

Adolescent↗
PubMed1998

The uterine capacity measured by the total twin birth weight and duration of twin pregnancy.

The objective of this study was to answer the question whether there is the relation between the uterine capacity, estimated by the total birth weight of fetuses, and the duration of twin gestation. The material for researches contains data received from the books of births and case records concerning the pregnant who gave births to twins in the Institute of Obstetrics and Gynecology of the Medical University in Lódź between 1970-1998. The final analysis concerned only gestations lasting more than 29 weeks, without any complications (excluding prematurity and the growth-discordant twins), and when gestational age was exactly known. The selected group was finally composed of 188 pairs of twins. The analyses considered relations between total birth weight of twins, the sex of newborn babies, parity, and the duration of gestation. The duration of the analyzed twin pregnancies was 35.6 weeks, including primiparous with 35.8 weeks, and multiparous--35.1 weeks. In the group of male-male twin pairs the average duration of pregnancy was 35.7 weeks, in unlike-sexed pairs--35.6 weeks, and in female-female pairs--35.5. In the group of the primiparous having male-male twin pairs the average duration of pregnancy was 35.1 weeks, unlike-sexed pairs--36.4 weeks and female female pairs--36.6 weeks, while in the group of multiparous relatively: 36.4, 35.4, 35.0 weeks. The total birth weight of the specific pairs of twins was from 2270 g to 6900 g (average 4794 g), while in 92% < 5500 g. In the primiparous group it was 4908.1 g. and in the multiparous group--4663.1 g. Analyzing the total twins' weight according to the fetal gender and parity it was found that in primiparous with male-male twins--4715.3, unlike-sexed--5271.6 and female-female--4967.5, whereas in multiparous relatively: 4961.5, 4692.6, 4414.0. The shortening of twin pregnancies was caused by the following factors: total body mass achieved by fetuses was > 5500 g, presence of male sex in twin pregnancies (only in primiparous), and also the multiparity.

Birth Weight↗
PubMed1995

Slow twin conception at first birth and subsequent maternal twin proneness in a natural fertility population.

To study whether apparently more fecund women having delivered twins at first birth have traits of higher twin-proneness, we performed a retrospective cohort study on population-based historical vital records of the 17-18th century French Canadian immigrants and their descendants under natural fertility conditions. Among 24896 mothers who had at least one child, 248 had twin maternities at their first birth (twinning rate = 1.0%). Among 21508 mothers with a valid marriage-first birth interval, twinning rate was 0.97% among prompt conceptions (7.0-11.0 months), with a particularly high rate at the interval of 7.0-8.0 months (2.2%). Marriages in August-October resulted in a higher twinning rate particularly for the slow conceptions than those in the other seasons. Promptly-conceived mothers of twins at the first delivery may seem to have higher fecundity, but subsequent births from these mothers (n = 88) show a lower twinning rate (1.7%) particularly at younger maternal age than from the other mothers who had slowly conceived twins at their first birth (n = 112). The latter show a 4.5% twinning rate as a whole among their second or later births. So-called twin-proneness of a mother, whether genetic or acquired, was not connected to higher conception rate of twin's mothers immediately after marriage. Reduced fecundity, which may have been imposed by some environmental factors, could raise the chance of twinning.

Adult↗
PubMed2003

Neonatal course and outcome of twins from reduced multifetal pregnancy versus non-reduced twins.

BACKGROUND: Multifetal pregnancy reduction has been implemented for improving the outcome of multifetal pregnancies. Recent studies reported no difference in pregnancy outcome between reduced twins and non-reduced twins, but the neonatal course and subsequent outcome in reduced twin pregnancies were not well documented. OBJECTIVE: To compare the neonatal course and outcome, as well as the gestational and labor characteristics in twins from reduced multifetal pregnancies and in non-reduced twins. METHODS: This is a retrospective case-control study of the neonatal course of twins from reduced multifetal pregnancies. We found 64 mothers with multifetal pregnancy reduction who delivered twins during 1989-1997; 64 gestational age-matched non-reduced twin pregnancies served as controls. The following neonatal variables were examined: major malformations; small birth weight for gestational age; and neonatal morbidities including respiratory distress syndrome, apnea, pneumothorax, bronchopulmonary dysplasia, hyperbilirubinemia, sepsis, necrotizing enterocolitis, retinopathy of prematurity, seizures, intraventricular hemorrhage, periventricular leukomalacia, ventriculomegaly, and hydrocephalus. In addition, we evaluated several neonatal interventions (surfactant replacement, mechanical ventilation, phototherapy, total parenteral nutrition), and some laboratory abnormalities (thrombocytopenia, leukopenia, anemia, and hypoglycemia), duration of hospitalization, and neonatal mortality. RESULTS: Gestational and labor variables were not significantly different between multifetal pregnancies reduced to twins and non-reduced twin pregnancies. The neonatal morbidity and mortality were not significantly different between twin neonates from multifetal pregnancy reduction and non-reduced control twins. CONCLUSIONS: Multifetal pregnancy reduction to twins appears to bear no adverse effect on the intrauterine course of the remaining fetuses or their neonatal course and outcome when born after 28 weeks of gestation.

Case-Control Studies↗
PubMedDate not supplied

Liveborn twin with intrauterine death of one twin: report of two cases.

Twin pregnancies carry a greater mortality and morbidity rate than singleton pregnancies. In case of an intrauterine fetal death (IUFD), the risk of mortality and morbidity of the surviving twin is increased. The pathogenesis is usually due to twin to twin transfusion. The donor twin is hypovolemic, anemic and often shows a growth retardation or even severe enough to cause an IUFD. The recipient twin is hypervolemic, polycythemic and weighs more than its co-twin. In this paper we reported two cases of liveborn twin complicated by an IUFD of its co-twin. Both cases were monochorionic twins. The first case was born at 29 weeks and 6 days of gestation, a male infant weighed 1054 g. His co-twin was stillborn and weighed 722 g. At birth the surviving infant showed respiratory distress syndrome (RDS), anemia and bilateral periventricular echogenicity (PVE). The second case was a female infant with a gestational age of 26 weeks and 2 days and weighed 850 g. Her stillborn co-twin weighed 804 g. Both twins showed signs of hydrops, and the liveborn infant had RDS, marked anemia (Hb 6 g/dl) and hypoalbuminemia. We will discuss the possible pathogenesis in our cases and also review some literature.

Echoencephalography↗
PubMedDate not supplied

[Abnormal twin pregnancy--early resorption of a single fetus in a twin pregnancy pregnancy].

INTRODUCTION: Twin pregnancy presents a condition of development of two fetuses in the uterus and can be monozygotic (single ovum) and dizygotic (two ova). In case of fertilization and segmentation of one ovum monozygotic twins are produced, while in case of fertilization of two ova, which can originate from one or two Graff follicles, dizygotic twins are developed. The ratio of twin and single pregnancies is 1:89 (according to Hellin's law) (1). The incidence of twin and other multiple pregnancies is influenced by: race of parents, age and parity of mother, use of clomid and gonadotrophin to stimulate ovulation, discontinued use of contraceptive pills and certain seasons (exposure to sunlight) (1). Due to occurrence of numerous complications twin pregnancy and parturition are considered to be highly risky. This is supported by clinical data on more frequent spontaneous abortions--especially in monozygotic pregnancies, hypertension in pregnancy, hemorrhage of various etiologies, anemias, early rupture of amniotic membranes, hydramnios, premature deliveries, etc. Nowadays diagnosis of both twin and other multiple pregnancies in the early stage is required, in order to establish normal or pathological development of such pregnancies. As early as 6 gestation week in twin pregnancies it is possible to sonographically visualize two gestation sacs in the uterus, while in 7-8 gestation weeks it is possible to see two embryos with evidence of fetal heart rate. In early pregnancy a differentially-diagnosed uterus may be clinically enlarged due to: hydratidaform mole, uterine mioma or ovarian cyst. In later gestation confirmation of twin pregnancy is possible by clinical and sonographic examination and biochemical analyses (elevated values of HPL and -fetoprotein) and less frequently, by x-ray. Repeated sonographic examinations can reveal the following anomalies of twin pregnancies: one normal pregnancy with one sac containing no embryo, one sac containing no embryo and one sac with a dead fetus, fetuses without vitality in both gestation sacs, two ultrasound echoes from which only one normal fetus and one dead mummified fetus (fetus papiraceus) result within the uterus. One gestation sac may be resorbed during pregnancy, while the undamaged fetus continues to develop normally in the uterus. In certain cases the loss of one fetus is not accompanied by any clinical symptoms, and in others this can be accompanied by light hemorrhage. An initial twin pregnancy after the loss of one twin may end by a birth of one healthy infant. CASE REPORT: A patient aged 35 years, came for gynecological examination due to missed menstruation. Ananmesis showed that she had a nascent uterine myoma which was removed by myomectomy six months earlier, had one parturition four years earlier, and no abortions. The last menstrual period was on February 12, 1991. Clinical examination showed a somewhat larger uterus than would be normal for amenorrhea of 9-gestation week. By sonographic examination two regular gestation sacs were found in the uterus with fetal echoes present as well as heart rate in both fetuses (Figure 1). Embryo measurements were as follows: Fetus 1-CRL-22.5 mm, NEG-8 + 4, heart rate present. Fetus 2-CRL-23.6 mm, NEG-9, heart rate present (Figure 2). The patient was cautiously informed that two fetuses are visible in the uterus and that this is a sign of twin pregnancy, but for certain diagnosis a control examination was scheduled two weeks later. The sonographic examination after 14 days later showed discord in fetal growth (Figure 3). Embryo measurement in 11-gestation week rendered the following parameters: Fetus 1-CRL-22.8 mm, NEG 8 + 6, no heart rate registered (Figure 4), while the second fetus continued to develop and had the following characteristics: Fetus 2-CRL-50.5 mm, NEG 11 + 4, heart rate and fetal movement registered (Figure 5). During entire pregnancy the patient suffered no pain or any kind of hemorrhage. She took no drugs. (ABST

Adult↗
PubMed2005

A twin study of genetic and dietary influences on nephrolithiasis: a report from the Vietnam Era Twin (VET) Registry.

BACKGROUND: Nephrolithiasis is a complex phenotype that is influenced by both genetic and environmental factors. We conducted a large twin study to examine genetic and nongenetic factors associated with stones. METHODS: The VET Registry includes approximately 7500 male-male twin pairs born between 1939 to 1955 with both twins having served in the military from 1965 to 1975. In 1990, a mail and telephone health survey was sent to 11,959 VET Registry members; 8870 (74.2%) provided responses. The survey included a question asking if the individual had ever been told of having a kidney stone by a physician. Detailed dietary habits were elicited. In a classic twin study analysis, we compared concordance rates in monozygotic (MZ) and dizygotic (DZ) twins. We also conducted a cotwin control study of dietary risk factors in twins discordant for stones. RESULTS: Among dizygotic twins, there were 17 concordant pairs and 162 discordant pairs for kidney stones. Among monozygotic twins, there were 39 concordant pairs and 163 discordant pairs. The proband concordance rate in MZ twins (32.4%) was significantly greater than the rate in DZ twins (17.3%) (chi(2)= 12.8; P < 0.001), consistent with a genetic influence. The heritability of the risk for stones was 56%. In the multivariate analysis of twin pairs discordant for kidney stones, we found a protective dose-response pattern of coffee drinking (P= 0.03); those who drank 5 or more cups of coffee were half as likely to develop kidney stones as those who did not drink coffee (OR = 0.4, 95% CI 0.2, 0.9). Those who drank at least 1 cup of milk per day were half as likely to report kidney stones (OR = 0.5, 95% CI 0.3, 0.8). There were also marginally significant protective effects of increasing numbers of cups of tea per day and frequent consumption of fruits and vegetables. Other factors such as the use of calcium supplements, alcohol drinking, consumption of solid dairy products, and the amount of animal protein consumed were not significantly related to kidney stones in the multivariate model. CONCLUSION: These results confirm that nephrolithiasis is at least in part a heritable disease. Coffee, and perhaps tea, fruits, and vegetables were found to be protective for stone disease. This is the first twin study of kidney stones, and represents a new approach to elucidating the relative roles of genetic and environmental factors associated with stone formation.

Diet↗
PubMed2002

The Danish Twin Registry: 127 birth cohorts of twins.

The Danish Twin Registry is the oldest national twin register in the world, initiated in 1954 by ascertainment of twins born from 1870 to 1910. During a number of studies birth cohorts have been added to the register, and by the recent addition of birth cohorts from 1931 to 1952 the Registry now comprizes 127 birth cohorts of twins from 1870 to 1996, with a total of more than 65,000 twin pairs included. In all cohorts the ascertainment has been population-based and independent of the traits studied, although different procedures of ascertainment have been employed. In the oldest cohorts only twin pairs with both twins surviving to age 6 have been included while from 1931 all ascertained twins are included. The completeness of the ascertainment after adjustment for infant mortality is high, with approximately 90% ascertained up to 1968, and complete ascertainment of all liveborn twin pairs since 1968. The Danish Twin Registry is used as a source for large studies on genetic influence on aging and age-related health problems, normal variation in clinical parameters associated with the metabolic syndrome and cardiovascular diseases, and clinical studies of specific diseases. The combination of survey data with data obtained by linkage to national health related registers enables follow-up studies both of the general twin population and of twins from clinical studies.

Aging↗
PubMed2001

Perinatal morbidity and mortality rates in severe twin-twin transfusion syndrome: results of the International Amnioreduction Registry.

OBJECTIVE: Serial aggressive amnioreduction is the most widely used therapy for pregnancies that are complicated by twin-twin transfusion syndrome. Survival rates reported with this therapy are 33% to 83%, the wide range attributable to the small number of patients in these case series. Similarly, data on morbidity in survivors are imprecise. We instituted the international twin-twin transfusion syndrome registry to determine the perinatal survival and morbidity rates and the factors that influence perinatal outcome in patients with twin-twin transfusion syndrome who were treated with serial aggressive amnioreduction from 1990 to 1998. STUDY DESIGN: A total of 223 sets of twins who were diagnosed with twin-twin transfusion syndrome before 28 weeks' gestation from 20 fetal medicine referral centers were analyzed, with follow-up data until 4 weeks after birth. RESULTS: Three hundred forty-six twins (78%; 182 recipients and 164 donors) were born alive. Two hundred sixty-six twins (60%; 144 recipients and 122 donors) were alive 4 weeks after birth. Both fetuses survived to 4 weeks in 108 pregnancies (48.4%), whereas, at least 1 fetus survived in 158 pregnancies (70.8%). The interval between the last amnioreduction and delivery ranged from zero to 138 days (median, 17.5 days). In the infants who survived to 4 weeks after birth, abnormalities on neonatal cranial scan were diagnosed in 24% of recipients and in 25% of donors. Logistic regression analysis indicated that the survival rate was significantly related to gestational age at diagnosis, presence of end-diastolic blood flow in the umbilical artery velocity waveforms, presence of hydrops, mean volume of amniotic fluid removed per week, larger birth weight, and gestational age at delivery. The hemoglobin level difference at birth was the only significant parameter to predict abnormal cranial ultrasonography in newborns. CONCLUSION: These data document perinatal survival and neonatal morbidity rates in severe twin-twin transfusion syndrome that were treated by serial aggressive amnioreduction. Outcome was influenced by several perinatal risk factors, which may be used to counsel patients before and during therapy.

Amnion↗
PubMed2004

Twin-twin transfusion syndrome: a population-based study.

OBJECTIVE: To study the incidence and mortality and morbidity rates of twin-twin transfusion syndrome in a complete population-based cohort in Nova Scotia. METHODS: A population-based cohort study of all monochorionic diamniotic twin pregnancies of 20 weeks of gestation or longer born to Nova Scotia (Canada) residents between 1988 and 2000 was examined. The effect of gestational age adjustment and birth weight discordancy of more than 20% on mortality and 1-year survival was studied. Other outcomes studied included birth depression, respiratory distress syndrome, chronic lung disease, interventricular hemorrhage, periventricular leukomalacia, acute renal failure, and congestive heart failure. RESULTS: Of 404 monochorionic-diamniotic twin pregnancies examined, 48 were identified with twin-twin transfusion syndrome. Total mortality rates per pregnancy were significantly greater in the twin-twin transfusion syndrome group than in the remainder of our monochorionic diamniotic population (P < .01). However, when adjusted for gestational age, mortality failed to achieve statistical significance. Similarly, no differences were noted for 1-year survival and other outcomes of liveborn infants after gestational age adjustment. Discordance in birth weight predicted a higher incidence of morbid outcomes per pregnancy, but this effect was lost after gestational age adjustment. CONCLUSION: Increased morbidity and mortality of twins with twin-twin transfusion syndrome is likely to be due to a higher incidence of preterm birth. Birth weight discordancy was not found to be an independent predictor of mortality after controlling for gestational age and twin-twin transfusion syndrome.

Birth Weight↗
PubMed1991

Antenatal diagnosis of twin-twin transfusion syndrome by Doppler ultrasound.

We evaluated 31 pairs of twins: six with twin-twin transfusion syndrome, four discordant, and 21 concordant twins. The criterion for the retrospective diagnosis of discordancy was a difference in birth weight of 20% of the larger infant's weight. Using pulsed Doppler evaluation of the umbilical artery of each twin, the pulsatility index (PI) was used to evaluate the umbilical arterial waveforms. The differences in the PI from the twin-twin transfusion syndrome cases between 24-31 weeks significantly exceeded those of the cases without this syndrome (P less than .05). Seven cases had inter-twin differences in PI above 0.5, six of which had the twin-twin transfusion syndrome. The difference in PI seemed to predict the risk of twin-twin transfusion syndrome: The difference was high before the appearance of hydrops fetalis in those with this syndrome, whereas the difference in PI from discordant twin cases, except for those with the syndrome, was low.

Female↗
PubMed1993

Zygosity diagnosis of twins by questionnaire for twins' mothers.

Subjects were 74 twin pairs, 61 MZs and 13 same-sexed DZs who entered the High School affiliated with Tokyo University, Japan. Their mothers also participated. The twins' zygosity was previously identified by many genetic markers. This study aimed at clarifying the effectiveness of zygosity diagnosis by questionnaires distributed to twins' mothers. The questionnaire consisted of three questions concerning the degree of similarity of twins at one year of age; whether they were confused, and if so, by whom. It was slightly modified from that reported earlier by Ooki et al [11] for twins themselves. According to the degree of similarity of the twins, points were allotted thus: from 1 to 3 points for answers to questions (1) and (2) and from 1 to 4 points for answers to questions (3). The sum of the points was calculated, then ranged from 3 to 10. Zygosity was determined by the sum of these points. If the sum was 3-6, the twin pairs were considered MZ and if the sum was 7-10 DZ. It was revealed that more than 90% of twins were identified correctly as MZ or DZ by applying this cutting point and this result was in accordance with that obtained by use of discriminant function analysis. Moreover, the accuracy of the mothers' responses was nearly the same as that obtained by the questionnaire for twins themselves. It was concluded, therefore, that the information from twins' mothers is as correct as that from twins themselves. This questionnaire is simple, practical and especially useful when twins are still too young to participate personally.

Diagnosis↗