Campbell D, Thompson B, Pritchard C, Samphier M
Department of Obstetrics and Gynaecology, University of Aberdeen, Scotland.
Acta Genet Med Gemellol (Roma). 1987;36(3):409-15. doi: 10.1017/s0001566000006176.
Data based on total births from a geographically defined population with zygosity determined from blood samples and placentation and with data on the use of oral contraceptives routinely collected in early pregnancy showed no association between oral contraceptive use prior to pregnancy in either MZ or DZ twinning. Three mutually exclusive control groups of singletons were used to take account of age, parity and secular trends.
基于对一个地理区域界定人群的总出生数据，通过血样和胎盘情况确定双胎类型，并常规收集早期妊娠时口服避孕药使用情况的数据，结果显示无论是同卵双胞胎还是异卵双胞胎，妊娠前口服避孕药的使用与双胎类型之间均无关联。使用了三个相互独立的单胎对照组来考虑年龄、产次和长期趋势。
