TY - JOUR

T1 - The East Flanders Prospective Twin Survey (Belgium)

T2 - a population-based register

AU - Loos, R

AU - Derom, C

AU - Vlietinck, R

AU - Derom, R

PY - 1998/12

Y1 - 1998/12

N2 - The East Flanders Prospective Twin Survey (EFPTS), started in 1964, is unique among the 17 major European twin registers because it is population based, the twins (and higher order births) are ascertained at birth, basic perinatal data are collected, chorion type is established and, when appropriate, genetic markers including DNA fingerprints, are determined. The total number of sets is 5089 twin, 158 triplet and 14 of higher order. Zygosity has been diagnosed on the basis of sex, placental structure and genetic markers in more than 95% of pairs. The EFPTS is the only large register that includes placental data and allows differentiation of three subtypes of monozygotic twins based on the time of the initial zygotic division: the dichorionic-diamnionic pairs (early), the monochorionic-diamnionic pairs (intermediate), and the monochorionic-monoamnionic pairs (late). Methodology and basic results in twins are considered in this article; detailed studies will be reported later. The sex proportion in dizygotic (DZ) twins is the same as in singletons, whereas monozygotic (MZ) twins number more girls than boys. The difference in perinatal mortality between DZ and MZ twins is limited to the monochorionic MZ subgroup. Birth weight is highest in DZ twins and diminishes stepwise in MZ dichorionic and MZ monochorionic twins. Duration of pregnancy follows the same trend but is limited to a few days. Iatrogenic pregnancies are increasing to the point of representing almost 50% of the twin births in 1997.

AB - The East Flanders Prospective Twin Survey (EFPTS), started in 1964, is unique among the 17 major European twin registers because it is population based, the twins (and higher order births) are ascertained at birth, basic perinatal data are collected, chorion type is established and, when appropriate, genetic markers including DNA fingerprints, are determined. The total number of sets is 5089 twin, 158 triplet and 14 of higher order. Zygosity has been diagnosed on the basis of sex, placental structure and genetic markers in more than 95% of pairs. The EFPTS is the only large register that includes placental data and allows differentiation of three subtypes of monozygotic twins based on the time of the initial zygotic division: the dichorionic-diamnionic pairs (early), the monochorionic-diamnionic pairs (intermediate), and the monochorionic-monoamnionic pairs (late). Methodology and basic results in twins are considered in this article; detailed studies will be reported later. The sex proportion in dizygotic (DZ) twins is the same as in singletons, whereas monozygotic (MZ) twins number more girls than boys. The difference in perinatal mortality between DZ and MZ twins is limited to the monochorionic MZ subgroup. Birth weight is highest in DZ twins and diminishes stepwise in MZ dichorionic and MZ monochorionic twins. Duration of pregnancy follows the same trend but is limited to a few days. Iatrogenic pregnancies are increasing to the point of representing almost 50% of the twin births in 1997.

KW - Amnion/anatomy & histology

KW - Belgium/epidemiology

KW - Birth Weight

KW - Chorion/anatomy & histology

KW - DNA Fingerprinting

KW - Female

KW - Genetic Markers

KW - Humans

KW - Infant Mortality

KW - Infant, Newborn

KW - Male

KW - Multiple Birth Offspring/statistics & numerical data

KW - Placenta/anatomy & histology

KW - Population Surveillance

KW - Pregnancy

KW - Prospective Studies

KW - Registries

KW - Sex Distribution

KW - Triplets/statistics & numerical data

KW - Twins/classification

KW - Twins, Dizygotic/genetics

KW - Twins, Monozygotic/genetics

U2 - 10.1375/136905298320566131

DO - 10.1375/136905298320566131

M3 - Journal article

C2 - 10100808

VL - 1

SP - 167

EP - 175

JO - Twin Research

JF - Twin Research

SN - 1369-0523

IS - 4

ER -