Sex ratios among Canadian liveborn infants of mothers from different countries

Joel G. Ray, David A. Henry, Marcelo L. Urquia

Research output: Contribution to journalArticleResearchpeer-review

26 Citations (Scopus)

Abstract

Background: 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. Methods: 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). Results: 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). Interpretation: 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.

Original languageEnglish
JournalCMAJ
Volume184
Issue number9
DOIs
Publication statusPublished - 12 Jun 2012
Externally publishedYes

Fingerprint

Sex Ratio
Mothers
Parity
Live Birth
Confidence Intervals
India
Ontario
Canada
Republic of Korea
Parturition
Birth Certificates
Vital Statistics
Philippines
Far East
Pakistan
China
Newborn Infant
Pregnancy
Population

Cite this

Ray, Joel G. ; Henry, David A. ; Urquia, Marcelo L. / Sex ratios among Canadian liveborn infants of mothers from different countries. In: CMAJ. 2012 ; Vol. 184, No. 9.
@article{7ab8f03b758b4e3e82e0cfa83c68c77b,
title = "Sex ratios among Canadian liveborn infants of mothers from different countries",
abstract = "Background: 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. Methods: 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). Results: 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). Interpretation: 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.",
author = "Ray, {Joel G.} and Henry, {David A.} and Urquia, {Marcelo L.}",
year = "2012",
month = "6",
day = "12",
doi = "10.1503/cmaj.120165",
language = "English",
volume = "184",
journal = "CMAJ",
issn = "0820-3946",
publisher = "Canadian Medical Association",
number = "9",

}

Sex ratios among Canadian liveborn infants of mothers from different countries. / Ray, Joel G.; Henry, David A.; Urquia, Marcelo L.

In: CMAJ, Vol. 184, No. 9, 12.06.2012.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Sex ratios among Canadian liveborn infants of mothers from different countries

AU - Ray, Joel G.

AU - Henry, David A.

AU - Urquia, Marcelo L.

PY - 2012/6/12

Y1 - 2012/6/12

N2 - Background: 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. Methods: 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). Results: 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). Interpretation: 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.

AB - Background: 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. Methods: 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). Results: 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). Interpretation: 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.

UR - http://www.scopus.com/inward/record.url?scp=84862123381&partnerID=8YFLogxK

U2 - 10.1503/cmaj.120165

DO - 10.1503/cmaj.120165

M3 - Article

VL - 184

JO - CMAJ

JF - CMAJ

SN - 0820-3946

IS - 9

ER -