Windham G C, Bjerkedal T
Acta Genet Med Gemellol (Roma). 1984;33(1):87-95. doi: 10.1017/s0001566000007558.
During 1967-79 the population-based Medical Birth Registry of Norway registered 7,660 twin pairs (1% of births) born to 7,596 mothers, who gave birth to 6,608 additional infants (twin siblings). The total rate of malformations among twins (278.1/10,000) was not significantly different than among singletons (302.1/10,000), nor among twin siblings (314.8/10,000). By specific type of defect, twins had significantly higher rates than singletons of central nervous system (CNS) defects (Rate Ratio = 1.8) and cardiovascular defects (RR = 1.5). The twins also had a significantly low rate of congenital hip dislocation (RR = 0.4), which may explain the relatively low incidence of malformations in twins. Like-sex (LS) twins had a slightly higher rate of malformations than unlike-sex (US) twins (RR = 1.1), as well as a higher rate of CNS defects (RR = 3.0). The siblings also had a significantly increased rate of CNS defects compared to singletons (RR = 1.9), but not of cardiovascular defects (RR = 0.9). The results indicate that twins have elevated rates of at least some congenital malformations. The observations about CNS defects suggest common factors that can lead to either like-sex twinning, CNS defects, or both. The increased frequency of cardiovascular defects in twins appears to be associated with the biologic conditions of twinning.
1967年至1979年间，挪威以人群为基础的医学出生登记处记录了7660对双胞胎（占出生人口的1%），其母亲为7596人，这些母亲还生育了另外6608名婴儿（双胞胎的兄弟姐妹）。双胞胎的畸形总发生率（278.1/10000）与单胎（302.1/10000）以及双胞胎的兄弟姐妹（314.8/10000）相比，并无显著差异。按特定缺陷类型来看，双胞胎的中枢神经系统（CNS）缺陷（率比=1.8）和心血管缺陷（RR=1.5）发生率显著高于单胎。双胞胎先天性髋关节脱位的发生率也显著较低（RR=0.4），这可能解释了双胞胎畸形发生率相对较低的原因。同性（LS）双胞胎的畸形发生率略高于异性（US）双胞胎（RR=1.1），中枢神经系统缺陷发生率也更高（RR=3.0）。与单胎相比，双胞胎的兄弟姐妹中枢神经系统缺陷发生率也显著增加（RR=1.9），但心血管缺陷发生率未增加（RR=0.9）。结果表明，双胞胎至少某些先天性畸形的发生率有所升高。关于中枢神经系统缺陷的观察结果表明，存在一些共同因素可导致同性双胞胎、中枢神经系统缺陷或两者兼而有之。双胞胎心血管缺陷发生率的增加似乎与双胞胎的生物学状况有关。
