Congenital Anomalies in Twins in Northern Ireland. II: Neural Tube Defects, 1974-1979

Abstract

In a large population-based study in Northern Ireland during the period 1974-1979, the rate of anencephalus in twins (9.1/10,000) was found to be less than that in singletons (24.3/10,000). This finding is in contrast with most other studies and the possibility of underascertainment of twin cases is considered, but it is concluded that chance is the likeliest explanation. The rate of spina bifida in twins (36.4/10,000) was similar to that in singletons (31.9/10,000). All of the twins with anencephalus were female and from pairs of like sex. Rates of spina bifida in twins from pairs of the two sex types were similar but, unusually, there was a male preponderance. As in previous studies, the great majority of twins with NTDs had unaffected cotwins.

Congenital anomalies in twins: a register-based study

“…Our observation that the most common anomalies in both twins and singletons were cardiovascular anomalies and the relative risk was higher for twins than singletons confirms previous reports (Windham and Bjerkedal, 1984;Kallen, 1986;Little and Nevin, 1989c;Pradat, 1992;Mastroiacovo et al, 1999;Li et al, 2003). We found that anomalies of the central nervous system were more common in twins than in singletons, a finding consistent with some earlier reports (Myrianthopoulos, 1976;Doyle et al, 1991;Mastroiacovo et al, 1999;Li et al, 2003) but not with others (Kallen, 1986;Little and Nevin, 1989b) which observed excess rates in twins for hydrocephaly (Kallen, 1986) but not for neural tube defects (Kallen, 1986;Little and Nevin, 1989b). Anomalies of the digestive system, in particular gut atresias, are also reported to be more common in twins (Kallen, 1986;Doyle et al, 1991;Mastroiacovo et al, 1999;Li et al, 2003).…”

Congenital Anomalies in Twins in Northern Ireland. I: Anomalies in General and Specific Anomalies Other Than Neural Tube Defects and of the Cardiovascular System, 1974–1979

“…In this paper, we present data from a large-scale population-based study in Northern Ireland, in which two sources of ascertainment, covering a period up to the end of the second month, were used. Elsewhere, associations between twinning and (1) neural tube defects [11] and (2) anomalies of the cardiovascular system [12] in this population are described and discussed.…”

Discordant anencephaly with a cleft lip and palate in a pergonal - induced triplet pregnancy

“…It occurs in a predictable, sporadic manner in approximately 1 in 1,000 live births [13] and despite extensive study, no consistent association has been found. Considerable geographic and seasonal variability has been documented with marked excess of female infants.…”