During a 5-year period twin births occurrring at the university hospital were investigated for the presence of clinical and biochemical symptoms of intrauterine hypoxia. It appears that intrauterine hypoxia, when detectable, is limited to the second twin. Some factors which may influence the oxygenation of the second twin have been analysed, i.e., the mode of delivery, the time interval between deliveries, and the duration of gestation. No single explanation for the genesis of the hypoxia seems to be valid.

A two-dimensional ultrasonic B scanner is used to diagnose both single and multiple early pregnancy The contact scanning method is used. The patient is required to have a full bladder if she is under 14 weeks gestation. The uterus and the cervix are outlined. Then a search is made for the gestation sac or sacs within the uterine cavity if the cyesis is under 10 weeks. Serial longitudinal and transverse scans are carried out to outline the gestation sacs. The fetal echoes within the gestation sac are seen and the fetal heart rate can be detected using the time-position display (TP). The patients that are studied fall into the following groups: (1) patients who are clinically suspected to have multiple pregnancy; (2) patients who have been on ovulation induction therapy; (3) patients with family history of twins; (4) patients with threatened abortion. The diagnosis of multiple pregnancy during the 11th week is equivocal. After the 12th week gestation the diagnosis is made by visualising the fetal head and the maturity is then estimated by measuring the biparietal diameter. Thus fetal growth can be assessed by carrying out serial biparietal diameter estimations.

The perinatal mortality rate for twin gestation is in the range of 15 %, and this is due predominantly to prematurity, although twins may also be born growth retarded. Ritodrine HCl, a beta sympathomimetic drug, has been shown to be effective, both in stopping premature labor and in preventing intrauterine growth retardation. With this in mind, a double-blind study using ritodrine HCl or placebo was begun in order to study its effect on premature labor, intrauterine growth retardation, and the perinatal mortality rate in twins. Thus far, 30 patients have delivered and have been followed to 6 weeks postpartum. Although the results on individual patients have remained blinded to the investigators, an initial evaluation of the ritodrine and placebo groups have revealed no difference with respect to gestational age, birth weight, or perinatal mortality. These preliminary results are not significant. However, it appears that ritodrine HCl is a safe oral agent for the antepartum gravida and her fetus. The study will be continued until approximately 100 patients have been enrolled.

Twin pregnancies may present tubal involvement in the following cases: (1) simultaneous intra- and extrauterine pregnancy; (2) interstitial bilateral pregnancy (either simultaneous or not); (3) multiple pregnancy in the same tube; and (4) simultaneous interstitial and ovarian pregnancy.

Interstitial bilateral pregnancy appears to be by far the rarest kind of tubal twin pregnancy, apparently only one case having been reported in the literature, and this referring to a nonsimultaneous pregnancy. A case is now reported that therefore appears to represent the first observation of simultaneous interstitial bilateral pregnancy.

A retrospective study of 127 twin pregnancies has been carried out, considering the relation between maternal weight-gain and zygosity of the ovum. At 28 weeks of gestation, the maternal weight-gain distribution goes on according to a bimodal curve, the analysis of which shows that each pike corresponds to one twin-pregnancy variety. Whatever the considered term might be (28-32-36 weeks), the maternal weight-gain is higher in DZ than in MZ pregnancies, and it should be pointed out that toxemic pregnancies, in each group, have nothing to do with this difference. This maternal weight-gain difference may reflect the known quality difference between MZ and DZ ova. The data lead to set up the more general hypothesis of an ovular regulation factor of the maternal weight-gain, in addition to classic data such as the own fetal weight, its annexes, and maternal diet.

Among 1195 twins born in the Collaborative Perinatal Project, for whom information was available, 219 (18.33%) were found to have malformations, 179 (14.98%) single and 40 (3.35%,) multiple. The frequency of malformations among twins was significantly higher than that among singletons from the same population, but the difference was entirely contributed by MZ twins. This holds true for both major and minor malformations. The frequency among Negro twins was higher than among white, and among male twins higher than among female. Twins had more malformations of the central nervous, musculoskeletal, ear, respiratory, cardiovascular, and alimentary systems and fewer malformations of the genitourinary and integumentary systems than singletons. In a significant number of cases when one twin of a pair had a malformation, the cotwin also had a malformation though not necessarily the same as that of the first twin.

Two factors emerged from a search for obstetric phenomena that might explain concordance of leukemia in both members of a twin pair within days or months of each other: antenatal exposure to ionizing radiation; and antenatal cojoined intrauterine circulation. In addition, antenatal tumor metastasis and chromosomal changes, antenatal or postnatal, may be contributory. Continued observation of reports should be carried out.

Twin psychology has been studied to a very limited extent. Only few remarkable peculiarities of the twins' development are known for sure, such as delayed intellectual development, language retardation with frequent cryptophasia, difficulties and fragility of self consciousness, reduced sociability. These and other peculiarities may result from a number of different factors: biological, peculiar parental attitude, and especially the twin situation itself, the psychology of the twin as an individual being a function of the psychology of the twin pair. Twin peculiarities have for a long time been ignored. On the one hand, psychology ignored the couple reality (it was a “one-body” psychology), and on the other, the twin method classically postulated that twins are not atypical and may therefore be used as a test for the general population. As a matter of fact, twin psychology opens a new way to science. The twin situation may serve as a paradigm for the general study of the couple effect, namely, for the objective analysis of personality as a consequence of the relations between self and others. For certain traits of personality, it is already known that MZ twins brought-up together are significantly less similar than MZ twins brought-up apart. In fact, couple effects may mask or considerably reduce genetic factors.

The Blacky Picture Test was administered to a sample of 12 pairs of male MZ twins, aged 17 to 19 years, and to an equal number of singletons. A score for 30 factors was assigned to each protocol. By comparing the scores of the two groups using the Mann-Whitney U test, only one significant difference emerged, relative to the factor concerned with positive identification and fraternal relationship. Twins chose the sibling figure as the identification object significantly less often than singletons did. A more qualitative elaboration was undertaken in order to interpret this result. From the final data, the pre-cariousness of the sense of identity in the twins comes out indirectly in their passive and conformistic acceptance of the paternal model. It would seem that the twin is induced by his relationship with his cotwin, seen as the origin of this uncertainty as to his own identity, to adhere closely to the paternal image.

The present study has confirmed previous evidence that young twins show a marked delay in language development. This delay averaged six months at the age of 48 months, compared to a control group of singletons; it was evenly reflected in all nine subtests of the Illinois Test of Psycholinguistic Abilities, and was shown equally in MZ and DZ twins. Biological variables such as birth weight, gestational age and reproductive complications were only weakly associated with language scores at four years. The twins were not significantly retarded on non-verbal tests of general intelligence, compared with population norms or with the singleton controls. Environmental factors, particularly social class and family size were strongly correlated with language scores, though the association was stronger in singletons than in twins. Middle class twins were relatively much more retarded in language development compared with middle class singletons than working class twins compared with working class singletons. Comparison of intra-class correlations between 28 MZ and 64 DZ pairs yielded a heritability index of 44% for the test as a whole, with considerable variations in h2over the nine subtests. Heritabilities were highest for tests sampling the visual motor channel, and lowest for tests on the auditory-vocal channel. In confirmation of this finding, an examination of the test profiles of the singleton controls suggested that social class differences were most marked on tests of the auditory-vocal channel. It is suggested that the latter are more susceptible to environmental variables.

The delay in the development of the language often found in twins is usually interpreted as being strictly connected with the twinning situation and on the assumption that a model of verbal, tendentially crypto-phasic, communication would more easily exist between twins. Two types of language pathology in twins, diverging from this classic framework, are presented: (1) Developmental dyslalia (or developmental dysarthria); in these cases no abnormality could be found in the modality of verbal communication between the cotwin; (2) Developmental dysphasia; in these cases not only no tendency toward cryptophasia was observed, but indeed the verbal communication between the twins was markedly reduced. These two types of language disorders, as well as the classic one, are discussed in the light of a neurolinguistic interpretation.

A total of 63 twin pairs (22 MZ and 41 DZ), with one or both members affected by not organic stuttering and/or tics, have been drawn out of the Mendel Institute's twin file. Concordance of stuttering was observed in 10:12 MZ, but only in 2:19 DZ twin pairs; concordance of tics in 6:10 MZ and in 2:22 DZ twin pairs. Stuttering did not come out significantly associated either with other disturbances of language or with an IQ under the average; almost always it was possible to find out a precipitating factor. Significant relations between stuttering and tics could not be stated. Sex ratio, obtained regarding any affected subject separately, clearly turned in favour of males both in stuttering (32:12) and in tics (27:12). Stutterers and left-handers incidence in the families of stuttering subjects appeared significant in comparison with families of subjects with tics.

Analysis of mental and motor tests scores and intelligence test performance of twins born in the Collaborative Perinatal Project shows that twins perform more poorly than singletons from the same population and that the differences are greater in Negroes than in whites. The poor performance of twins relative to that of singletons is of complex etiology. It is partly due to poor prenatal environment, for twins brought up as singletons perform at the intelligence level of twins and not of singletons. It may also be partly due to the higher incidence of congenital malformations in twins, especially those of the central nervous system. But the performance of twins, relative to that of singletons, tends to improve as they get older, at least from 4 to 7 years, suggesting that prematurity is also a contributing factor, whose detrimental effects may be reversible.

Some Psychopathologic problems occurring during childhood in twins are discussed from the point of view of mental health. On the basis of case history of twins affected by neurologic or psychiatric disorders some typical situations have been examined: (1) Psychopathologic problems arising from perinatal death of the cotwin; (2) Psychopathologic problems arising from the death of the cotwin during late childhood; (3) Psychopathologic problems arising in the pair from organic or neuropsychaitric event in one of the twins; (4) Psychopathologic problems of the twins due to disorders of personal identity and the interaction between the twins. The cases are analyzed from a psychodynamic point of view, in relation to the development of personality in the twins, and from a psychosocial point of view, in relation to the cultural stereotype of the twins during the socialization process and in the context of parental dynamics.

In 1973 the Mendel Institute, within the specialized services it offers to Italian twins, instituted psychopedagogic counseling for twins and their families. This service is carried out in the intermediate field between neuropsychiatry and social work. Cases involving family and social maladjustment were referring for counseling. During the academic year 1973-1974, the service examined 96 cases, of which 58 involved problems of school retardation and 38 involved family maladjustment because of changed parent-twin relationships. The counseling service aimed at achieving improved family and school relationships by means of various therapeutic interventions. The psychopedagogic counseling, besides the immediate therapy, has permitted deeper study of maladjustment by means of analyses of the twins' condition as a possible additional cause of the maladjustment itself. Analysis of the cases in this limited sample would seem to indicate an indirect incidence of the twin situation per se (couple effect), somewhat emphasized by the family and social environment.

It is both an honor and a pleasure to stand before you today to take a small part in the First International Congress of Twin Studies.

For several years, we have dreamed of someday visiting the Mendel Institute. We first became aware of Dr. Luigi Gedda's work with twins in a psychology class at the State University of Iowa, in Iowa City, Iowa, in 1954. We are here today as Ambassadors-at-large of a rather unique organization for twins - the International Twins Association, Inc.

The International Twins Association, Inc (I.T.A.) was organized By and For Twins in 1932. Rev. Edward M. Clink of Silver Lake, Indiana, U.S.A. was on a tour of the United States. He encountered several sets of twins and thought that they should get together. He and his twin sister, Elsie Clink inserted an article in several newspapers requesting twins to bring a basket dinner to Center Park in Warsaw, Indiana, on Sunday, August 29, 1932. Twenty-four sets of twins were present at that first meeting.

One year later, a basket dinner was served to 200 sets of twins. And by the next year, 400 doubles and 2000 onlookers were present. The 4th annual meeting in Warsaw Park in Indiana in September 1935 found more than 900 sets of twins parading before 5000 spectators. That year, many states of the union were represented.

On August 1937, Fort Wayne's Trier Park in Indiana was host to 1,900 sets of twins for the 5th annual convention with 10,000 spectators. But the largest attendance, still unequalled to our knowledge, occurred the following year on August 29, 1937 when the National Twins became known as the International Twins Association, Inc. An old newsclipping states that 20,000 twins were in attendance. At this time co-officers were elected (a set pf twins holding an office to emphasiee the twin idea), and By-laws written to govern the association. The International Twins Association, Inc. (I.T.A.) conventions were held in Fort Wayne until 1939. Then the conventions moved from city to city throughout the United States, giving more twins an opportunity to learn about this unique fraternal organization.

Local, State and National are the threefold cord that binds us together at Mothers of Twins Clubs. Local, State and National share a mutual responsibility and interdependence with one another. This threefold cord helps us to grow and develop our potential for the benefit of all. It is cooperation between the three levels that unites us and though each serves in different ways, each is vital to the full scope of Mothers of Twins Clubs.

On the Local level we realize that research is the responsibility of every member and some clubs have research participation as a requirement of membership. Researchers could insure greater participation if they would issue periodic progress reports. Though we realize research is a long, slow process, we are often asked, “Why fill out forms if we never hear what is done with them?”. Mothers of Twins Clubs are glad to make time for research if they are made to feel it is worthwhile. Since some clubs belong to State or National, while others belong to State and National and still others belong to neither State or National, research work on the Local level has different outlets. The prime concern of the Local Mothers of Twins Club however is to learn to raise our twins as individuals while respecting the bonds and blessings of twinship.

The bridge of States is loosely knit with great resources still untapped for research. The growing number of State groups and the ever changing needs of Locals require the combined efforts of State Mothers of Twins Clubs to participate in Interstate communications and cooperation. There are 20 State groups in the U.S.A., representing over 303 clubs and over 9275 members. Most of the State groups have their own Research Chairman and Twin Registry. Those States without a Research Chairman are for the most part new groups and plan to participate in research when they are able. Even now State Mothers of Twins Club is being worked on by a group in Canada. Since more mothers can attend a State Convention, interest and enthusiasm for research on the State level is high among mothers of twins.

The dream began when an exuberant mother of identical twin girls engaged the help of a mother of identical twin boys to assist her in contacting already formed mothers of twins clubs (MOTC) throughout the state of Illinois. Their dream and their purpose then – and the purpose of the Illinois Organization of Mothers of Twins Clubs, Inc. (IOMOTC) now — was to join together socially and educationally member clubs throughout the state of Illinois and to exchange information pertaining to the rearing, development and recognition of the individuality of twins as may be forthcoming from parents, doctors, educators and other appropriate sources. The 16 charter clubs and 2 members-at-large became organized on October 20, 1962… thus a dream came true.

Today IOMOTC boasts a membership of 27 clubs and 1 member-at-Iarge for a total of 556 members and a voluntary executive board of 8 officers and 16 chairmen. All member clubs are self-governing. IOMOTC is noncommercial, nonpartisan, nonprofit and nonsectarian. Two sister clubs have the smallest membership (8 members each) and two clubs tie for the largest (48 members each). A bimonthly newsletter, Illinois State Saga, is available to all mothers of multiple births at a nominal cost. As part of their dues benefits, each member club receives copies of Saga. The second vice-president is always available to help either by mail, phone, or in person, any MOT's wishing to start a club or just wanting to join a club close to her home. Officers and chairmen are often invited to visit local clubs. This is valuable in bringing members up-to-date in the latest goings on in “state”.

My fascinating yet productive hobby began only with details of the delivery of quadruplets in my home city. The quadruplets were delivered by one of my psysician-employers and, because of predelivery contacts with the mother who was a member of my church, a scrap book about the quadruplets was started. Through outside pursuits, correspondence, detailed study and research this single scrap book has developed into what is believed to be the most extensive collection of authentic data and photographs of twins and supertwins in the world.

Files are kept as authentic as possible, yet by no means are internationally complete. Unfortunately, all multiple births are not recorded in medical, or public, registers and/or literature and some are never registered as multiple births due to circumstances surrounding the birth. A set of quadruplets about whom I have many news items from birth to age one year comes to mind… although the quadruplet birth was recorded by articles in newspapers, medical archives have no record of it because the physician expired before he formally recorded the birth in medical literature. Some births are recorded individually not indicating a multiple birth and others are lost because of a stillborn infant or a macerated fetus accompanying a live birth. Even parents are not always informed of the birth of a macerated fetus that accompanies a live birth.