Il termine LISREL e l'acronimo di LInear Structural RELationship ed è nato inizialmente come nome di un software messo a punto dallo svedese Karl Joreskog e dai suoi collaboratori nei primi anni '70 per stimare, col metodo della massima verosimiglianza, i coefficienti strutturali dei modelli basati su sistemi di equazioni strutturali.

Tali modelli, nella elaborazione tramite il LISREL, rappresentano la sistemazione logica, prima ancora che statistica o computeristica, di tecniche di analisi multivariata le cui prime proposte risalgono all'ininzio del secolo; riconducendo ad un unico modello che ne costituisce una geniale sintesi, approcci ed itinerari scientifici fino ad allora distinti e non comunicanti, quali l'analisi fattoriale, i modelli causali e i modelli di misurazione. In particolare rappresentano in questo momento la più completa e sistematica risposta al problema di operazionalizzare in termini di ricerca e di verifica empirica, nel campo delle scienze sociali, la controversa, ma non per questo meno fondamentale, nozione di causalità. Essi sono quindi la reinterpretazione, sistemazione e soprattutto generalizzazione di quelli che negli anni '60 venivano chiamati i modelli causali e che nella prima metà degli anni '70 avevano conosciuto una notevole popolarità fra i sociologi soprattutto attraverso la tecnica della path analysis.

There are a lot of publications about fetal arrhythmia in singletons, but up to now there are no published data about fetal arrhythmia in multiple pregnancies. In the present study a case history of fetal and neonatal arrhythmia in one of twins from two mothers treated with betamimetic agents due to imminent preterm labor is reported and discussed. A first case with fetal bradycardia due to complete A-V block had congenital cordis abnormalities (VSD and PFO). The second case with prenatal detected extrasystoles had normal heart anatomy. Digoxin was administered to the mother, in the aim to treat fetal arrhythmia without success, because the baby had postnatal bradycardia. After hospitalisation in Cardiology Department the described cases were successfully treated. In both cases the second twins were without neonatal arrhythmia and with no structural heart abnormalities. We summarise that in situation of detection fetal arrhythmia the complexity of the problems experienced may warrant early referral to a tertiary centre where the overall management of the mother, fetus and neonate, may be undertaken.

We described a case of pregnancy, delivery and peurperium of 28 years old multipara with twins pregnancy in bicornuate, unicollis uterus. Each fetus was placed in separate horn of uterus. Biological mature pregnancy was delivered by cesarean section. During the peurperium the involution disturbances of one of the uterus horns were observed. The case was discussed in context of other similar anomalies.

The frequency of the developmental dysfunction and specific learning disabilities were assessed in the retrospective study in the group of 56 school-aged twins. The relationships between genetic, perinatal and social factors and learning disability were also determined. It was found that 12.5% of twins had learning disabilities. The most common neurodevelopmental dysfunction were language disorders, poor graphomotor fluency and poor fine motor dexterity. It was also found that educational difficulty were associated with prematurity, low Apgar scores, neonatal complications and familial predisposition.

I studied 8 pairs of male twins and 14 pairs of female twins. The aim of this paper is to demonstrate the evaluation of development age in pairs of twins examined through the electrophoretical mobility of nuclei. EMN index in pairs of male twins, the index figures do not change dramatically between the ages of 8 – 12. EMN index in pairs of female twins rises from 9 – year – old to 11 – year – old pair. In this paper I want to indicate the studies on development age, which began at The Twins Festival in Szczecin in 1998.

Multiple pregnancies pose numerous threats both for foetuses and neonates. The following disorders are encountered among the most important perinatal disturbances: EPH – gestosis, immature labour and premature rupture of foetal membranes. Also during the labour, particularly the second one and the following ones, various lesions that may cause increased incidence of diseases and mortality in this group of neonates [5, 6, 10, 18, 21, 22, 25]. Complications encountered in neonates from multiple pregnancies, resulting both from abnormal conditions of intrauterine development and from perinatal pathology, require still wider studies, particularly within the context of intensified obstetrical care of women with multiple pregnancies [7, 11, 13, 16, 24].

In the years 1996-1998, out of 3883 neonates born in the Chair of Obstetrics and Gynaecology of the Silesian Medical Academy, 152 (3,9%) came from multiple pregnancies. This period included one case of quadruplets, eight cases of triplets and 62 twin pregnancies. Pregnant women were directed to our Chair within the program of multidisciplinary care of women with complicated pregnancies and they also came from the Department of Pathology of Pregnancy in our Chair. In 18 women, treated for infertility, the pregnancy was accomplished as a result of application of various techniques of assisted procreation. In one case – 4 foetuses were indicated, in five cases – three foetuses and in 12 cases – two foetuses.

Objective. The aim of this study was to show the diagnostic possibilities of ultrasound in twin-to-twin transfusion syndrome (TTTS), to demonstrate its usefulness in cases of hemoglobin difference < 5 g/dL in neonates as well as in cases complicated by intrauterine death of one or both twins.

Study design. The study included 4 pairs of twins. In two cases 3 fetuses died in utero. In the other two the hemoglobin difference in newborn infants was < 5 g/dL. The ultrasound examination, evaluating the fetal anatomy and biometry, amniotic fluid volume, placentation, was performed. The special attention was paid to polyhydramnios/oligohydramnios, discordant fetal growth (fetal weight, abdominal circumference), the presence of fetal hydrops, ascites, pericardial effusion. Doppler blood flow velocimetry has been done in umbilical vessels, middle cerebral artery. The data was compared with normal reference values for singleton pregnancies. The waveforms from both uterine arteries were also evaluated to exclude placental insufficiency. Additionally the blood flow through the AV valves was measured to exclude or confirm its regurgitation. Postnatally the hemoglobin difference was evaluated if available and compared with sonographic findings.

Results. In all cases inter-twin difference in abdominal circumference was greater than 18 mm and inter-twin weight difference of more than 15%. We observed polyhydramnios/oligohydramnios in all twin pregnancies.

It has been found decreased PI in middle cerebral artery in larger fetus (recipient) in all our cases (comparing to single pregnancy). PI values for this vessel in smaller fetuses were within normal range (for single pregnancy). PI values in umbilical arteries of recipients were abnormal (increased PI or absent end-diastolic flow).

Comments. The sonographic criteria seem to be very useful in diagnosis of twin-to-twin transfusion syndrome, especially in cases where the measurement of hemoglobin level is impossible. Doppler blood flow velocimetry in fetal vessels helps to explain the changes in fetal hemodynamics in TTTS.

The study comprised 14 pairs of twins. All the children were prematurely born between the 27 and the 33 weeks of pregnancy with birth weight 600-1900 g. Somatic development was assessed on the basis of the body weight, length/height measurements taken in the 6th and 12th months of the corrected age and in the 24th month of the calendar age. Body mass index was also calculated as weight in kilograms divided by the square of the height in meters. The obtained results were compared with the regional norms for children from Lodz. Moreover, in each child individual measurements and body mass index were normalized as compared to the arithmetic mean and the standard deviation for the established age norm. The percentage of children with body mass deficiency and decreased body length/height was relatively high. Individual assessment of somatic development, taking into account the normalized values enable observation of the direction of changes within the range of somatic features in individual children. Retardation of somatic development of prematurely born twins should be first of all associated with their very low birth weight. Severe complications of prematurity affect physical development of the children examined by us, especially in the first two years of life.

The study comprises 889 pregnant women between 14 and 21 weeks of gestation. The control group consisted of 862 pregant women with unburdened obstetric anamnesis with an uneventful singleton pregnancy. The examined group consisted of 27 pregnant women with uncomplicated twin pregnancy. In the sera of pregant women AFP (Microparticle Enzyme Immunoassay AxSYM Abbott), total (β-hCG (Microparticle Enzyme Immunoassay AxSYM Abbott) and unconjugated estriol (Radioimmunoassay Amerlex-M. 2T Johnson & Johnson Ortho Clinical Diagnostics Ltd.) were determined. The risk of fetal trisomy 21 was calculated with the use of PRISCA 3.0 software, which corrected the MoM values for twin pregnancy. Ulm Index was also calculated. In the majority of twin pregnancies increased concentrations of AFP, total (β-hCG and uE3 in the range over 1,0 MoM was noted. In the group of women below 35 years of age with singleton pregnancies using PRISCA 3.0 software it approximated to 95%. For women older than 35 optimum index for fetal trisomy 21 risk calculation was Ulm Index with the specificity 93,8%. The specificity of AFP determination in the detection of fetal open NTD in singleton pregnancy was 99%. In the group of women with twin pregnancy the obtained specificity of 77,8% for PRISCA 3.0 software is low, a more adavantageous way to calculate the risk of fetal trisomy 21 is Ulm Index with the specificity of 85,2%. The specificity of AFP determination as a screening for fetal open NTD in twin pregnancy was 96,3%.

The authors have analysed the frequency and structure of congenital anomalies in children born in the Pomeranian district in the period from 01.07.1997 to 31.12.1998. Among a total of 28.361 births in that area, 748 (2.64%) were affected by congenital anomalies. Among 28.361 births, 620 (2.18%) were from multiple pregnancies. 23 (3.71%) among births from multiple pregnancies were affected by congenital malformations. The prevalence rate of inborn anomalies in births from multiple pregnancy in our area were higher (3.71%) in comparison to births from singleton pregnancy (2.61%). It implies that children born from multiple pregnancy are at higher risk of developing congenital anomalies.