Repeated Multiple Maternities in Triplet Families

Human Reproduction, 2006

1992

Triplets are a relatively rare, occur rence being encountered in the Maltese Islands with an overall incidence of about 0.1 per 1000 maternities. The incidence appears to be on the increase over the last twenty years rising from the 0.08 per 1000 maternities in the decade 1960-69 to 0.11 per 1000 maternities in the following two dec ades. This increase has been correlated with the increasing use of ovulation induction agents, as has the occurrence of two quadruplets and one octuplet pregnancies in 1988-90. Triplets are shown to occur more frequently in eld erly mothers, but no relationship to parity could be identified. Higher or der births are shown to have a high incidence of antenatal and intrpartum problems, and are associated with a higher fetal loss than singleton preg nancies.

Hereditas, 2009

RASMUSON, M. and HED, H. 1981. A search for assortative mating and segregation abnormalities among motherchild-father triplets from paternity cases.-Herediras 94: 105-1 12. Lund, Sweden.

Seminars in Fetal & Neonatal Medicine, 2010

Twin pregnancy is associated with a high risk of congenital malformations. This review covers the risk of such anomalies in both dizygotic and monozygotic twin pregnancies, and discusses current insights into the associations relating to zygosity, chorionicity and genetic factors. The pathological basis of specific malformations unique to the monochorionic twinning process, including conjoined twinning and twin reversed arterial perfusion (TRAP) sequence, is discussed in more detail, and factors contributing to the higher perinatal mortality rate in multiple pregnancies are addressed.

Acta geneticae medicae et gemellologiae, 1994

American Journal of Medical Genetics, 1996

Twin blood group chimerism seems to be very rare in humans. The 30-40 previously reported cases usually were found by mere coincidence during routine blood grouping in hospitals or blood banks. Usually in these cases frank blood group mixtures of, for example, 50150%, 25175%, or 5195% at most were seen. Smaller percentages are very difficult to notice during routine work-up. Using a sensitive fluorescence technique (sensitivity >0.01%) we detected blood group chimerism in 321415 (8%) twin pairs and 12157 (21%) triplet pairs, respectively, which is a higher incidence than reported previously.

Early Human Development, 2006

Twins are a valuable resource not only for studies on multiple births themselves, but on the etiology of diseases and other phenotypes. The method of ascertainment and selection of twins can be crucial for such studies and population based twin registries are thus of great importance as tools of research.

2003

BACKGROUND: Folate metabolism is critical to embryonic development, in¯uencing neural tube defects (NTD) and recurrent early pregnancy loss. Polymorphisms in 5,10-methylenetetrahydrofolate reductase (MTHFR) have been associated with dizygotic (DZ) twinning through pregnancy loss. METHODS: The C677T and A1298C polymorphisms in MTHFR were genotyped in 258 Australasian families (1016 individuals) and 118 Dutch families (462 individuals) of mothers of DZ twins and a population sample of 462 adolescent twin families (1861 individuals). Haplotypes were constructed from the alleles, and transmission of the MTHFR haplotypes to mothers of DZ twins and from parents to twins in the adolescent twin families analysed. RESULTS: The C677T and A1298C were common in all three populations (frequencies > 0.29). There was strong linkage disequilibrium (D¢ = 1) between the variants, showing that speci®c combinations of alleles (haplotypes) were transmitted together. Three haplotypes accounted for nearly all the variation. There was no evidence of any association between MTHFR genotype and twinning in mothers of twins, or of the loss of speci®c MTHFR genotypes during twin pregnancies. CONCLUSIONS: It is concluded that variation in twinning frequency is not associated with MTHFR genotype.

Fertility and Sterility, 2015

Objective: To study the incidence of monozygotic twinning (MZT) in patients using in vitro fertilization, relative to their age, genetic background, ovarian function, and assisted reproductive techniques used. Design: Analysis of a collected database. Setting: Infertility treatment center. Patient(s): A total of 1,876 patients receiving infertility treatment between 2000 and 2012. Pregnancies with monozygotic twins (A: 23) were compared with deliveries of dizygotic twins (B: 423), singleton pregnancies (C: 880), and aborted pregnancies (D: 389). Intervention(s): None. Main Outcome Measure(s): A genetic survey on multiple pregnancies in the extended family. Measures were micromanipulation technique, the length of embryo cultivation, type of cultivation media, basal follicle-stimulating hormone level, estradiol level on the day of human chorionic gonadotropin administration, number of oocytes, total consumption of gonadotropins, and consumption of gonadotropins needed for recovery of 1 oocyte.

Acta geneticae medicae et gemellologiae, 1993

It is estimated that at least one dizygotic (DZ) twin maternity in twelve is preceded by superfecundation (the fertilization of two ova by sperm from different coitions). Presumably this parameter varies from population to population eg. with coital rates and rates of double ovulation. Sometimes superfecundation occurs by two different men. The frequency with which this occurs must depend on rates of infidelity (promiscuity). It is suggested that among DZ twins born to married white women in the U.S., about one pair in 400 is bipaternal. The incidence may be substantially higher in small selected groups of dizygotic twin maternities, eg. those of women engaged in prostitution.

2011

While humans usually give birth to singletons, dizygotic twinning occurs at low rates in all populations worldwide. We evaluate two hypotheses that have differing expectations about the effects of bearing twins on maternal lifetime reproduction and survival. The maternal depletion hypothesis argues that mothers of twins will suffer negative outcomes owing to the higher physiological costs associated with bearing multiples. Alternatively, twinning, while costly, may indicate mothers with a greater capacity to bear that cost. Drawing from the vast natural fertility data in the Utah Population Database, we compared the reproductive and survival events of 4603 mothers who bore twins and 54 183 who had not. These mothers were born between 1807 and 1899, lived at least to the age of 50 years and married once to men who were alive when their wives were 50. Results from proportional hazards and regression analyses are consistent with the second hypothesis. Mothers of twins exhibit lower postmenopausal mortality, shorter average inter-birth intervals, later ages at last birth and higher lifetime fertility than their singleton-only bearing counterparts. From the largest historical sample of twinning mothers yet published, we conclude that bearing twins is more likely for those with a robust phenotype and is a useful index of maternal heterogeneity.

Journal of Perinatal Medicine, 2000

1992

Few would dispute the truth of the statementPeople are Different', but there is much controversy over why. This book authoritatively explains the methods used to understand human variation, and extends them far beyond the primarynature or nurture'question. After chapters on basic statistics, biometrical genetics, matrix algebra and path analysis, there is a state-of-the-art account of how to fit genetic models using the LISREL package. The authors explain not only the assumptions of the twin method, but how to test them.

American Journal of Medical Genetics, 1996

The inheritance of spontaneous dizygotic (DZ) twinning was investigated in 1,422 threegeneration pedigrees ascertained through mothers of spontaneous DZ proband twins. DZ twinning was modelled as a trait expressed only in women. The penetrance was modelled first as a parity independent and secondly as parity dependent. The observed frequencies of maternal and paternal grandmothers with DZ twins differed significantly from the expectations under an X-linked mode of inheritance. Complex segregation analysis showed that the parity-independent phenotype of "having DZ twins" was consistent with an autosomal monogenic dominant model, with a gene frequency of 0.035 and a female-specific lifetime penetrance of 0.10. Recessive, polygenic, and sporadic models were rejected. The autosomal dominant model revealed a strong robustness against a changing population prevalence and the loss of information due to the presence of same-sexed twin pairs of unknown zygosity. When DZ twinning was modelled as a parity dependent trait, the data were compatible with an autosomal dominant model with a gene frequency of 0.306 and a penetrance of 0.03 per birth for female gene carriers. 0 1996 Wiley-Liss, Inc.