Department of Medicine, St. Michael's Hospital and University of Toronto, Toronto, Ont.
CMAJ. 2012 Jun 12;184(9):E492-6. doi: 10.1503/cmaj.120165. Epub 2012 Apr 16.
There has been much discussion about whether female feticide occurs in certain immigrant groups in Canada. We examined data on live births in Ontario and compared sex ratios in different groups according to the mother's country or region of birth and parity.
We completed a population-based study of 766,688 singleton live births between 2002 and 2007. We used birth records provided by Ontario Vital Statistics for live births in the province between 23 and 41 weeks' gestation. We categorized each newborn according to the mother's country or region of birth, namely Canada (n = 486,599), Europe (n = 58,505), South Korea (n = 3663), China (n = 23,818), Philippines (n = 15,367), rest of East Asia (n = 18,971), Pakistan (n = 18,018), India (n = 31,978), rest of South Asia (n = 20,695) and other countries (n = 89,074). We calculated male:female ratios and 95% confidence intervals (CIs) for all live births by these regions and stratified them by maternal parity at the time of delivery (0, 1, 2 or ≥ 3).
Among infants of nulliparous women, the male:female ratio was about 1.05 overall. As parity increased, the ratio remained unchanged among infants of Canadian-born women. In contrast, the male:female ratio was significantly higher among infants of primiparous women born in South Korea (1.20, 95% CI 1.09-1.34) and India (1.11, 95% CI 1.07-1.15) than among infants of Canadian-born primiparous women. Among multiparous women, those born in India were significantly more likely than Canadian-born women to have a male infant (parity 2, ratio 1.36, 95% CI 1.27-1.46; parity ≥ 3, ratio 1.25, 95% CI 1.09-1.43).
Our study of male:female ratios in Ontario showed that multiparous women born in India were significantly more likely than multiparous women born in Canada to have a male infant.
在加拿大，某些移民群体中是否存在女胎选择性堕胎一直存在争议。我们研究了安大略省活产儿的数据，并根据母亲的出生国或地区以及产次比较了不同人群的性别比例。
我们对 2002 年至 2007 年间出生的 766688 例单胎活产儿进行了一项基于人群的研究。我们使用安大略省生命统计部门提供的活产儿出生记录，这些记录是在妊娠 23 至 41 周期间在该省出生的。我们根据母亲的出生国或地区将每个新生儿分类，即加拿大（n=486599）、欧洲（n=58505）、韩国（n=3663）、中国（n=23818）、菲律宾（n=15367）、东亚其他地区（n=18971）、巴基斯坦（n=18018）、印度（n=31978）、南亚其他地区（n=20695）和其他国家（n=89074）。我们计算了所有这些地区的男婴：女婴比例和 95%置信区间（CI），并按产妇分娩时的产次（0、1、2 或≥3）对其进行分层。
在初产妇的婴儿中，总体男婴：女婴比例约为 1.05。随着产次的增加，加拿大出生的妇女所生婴儿的比例保持不变。相比之下，韩国（1.20，95%CI 1.09-1.34）和印度（1.11，95%CI 1.07-1.15）初产妇所生婴儿的男婴：女婴比例明显高于加拿大初产妇所生婴儿。在多产妇中，与加拿大出生的妇女相比，印度出生的妇女更有可能生育男婴（产次 2，比例 1.36，95%CI 1.27-1.46；产次≥3，比例 1.25，95%CI 1.09-1.43）。
我们对安大略省男婴：女婴比例的研究表明，与加拿大出生的多产妇相比，印度出生的多产妇更有可能生育男婴。
