Sex ratios at birth after induced abortion

Procedural abortion, provider-initiated preterm delivery and survival in pregnant people with cancer: A population-based cohort study

OBJECTIVE

To assess whether procedural-induced abortion or provider-initiated preterm delivery are associated with improved survival in pregnant people with cancer.

DESIGN

Retrospective population-based cohort study.

SETTING

Provinces of Alberta and Ontario, Canada, 2003-2016.

POPULATION

Females aged 18-50 years diagnosed with cancer at <20 weeks' (for the assessment of procedural-induced abortion) or <37 weeks' gestation (for the assessment of provider-initiated delivery).

METHODS

Cox proportional hazard models assessed all-cause mortality in relation to procedural-induced abortion and provider-initiated preterm delivery, adjusting for cancer site, stage at diagnosis and age. Meta-analysis pooled the results across both provinces.

MAIN OUTCOME MEASURES

All cause mortality.

RESULTS

There were 512 pregnant people diagnosed with cancer at <20 weeks' gestation and 782 diagnosed with cancer at <37 weeks' gestation. Neither procedural-induced abortion (adjusted hazard ratio [aHR] = 1.39, 95% CI: 0.32-6.17) nor provider-initiated preterm delivery (aHR = 1.17, 95% CI: 0.76-1.81) were associated with improved survival following adjustment for age, stage at diagnosis and cancer site.

CONCLUSIONS

Neither procedural-induced abortion nor provider-initiated preterm birth was associated with improved survival in pregnant people diagnosed with cancer; however, these obstetric interventions are highly personal decisions best decided by the pregnant person in consultation with their care providers.

Gender-based discrimination and son preference in Punjabi-Canadian families: a community-based participatory qualitative research study

OBJECTIVES

To conduct a qualitative study, guided by the principles of community-based participatory research, with the following objectives: (1) to provide a conceptual framework describing the drivers of son preference; (2) to understand experiences of son preference among Punjabi-Canadians and (3) with this understanding, identify and co-design an appropriate educational tool.

DESIGN, SETTING, PARTICIPANTS, METHODS

Qualitative study consisting of four bilingual (Punjabi and English) focus group discussions with 11 mothers, 4 fathers and 17 grandmothers in Toronto and Brampton, Canada. Participants were queried about experiences and perspectives related to reproductive decision-making, gender equity and son preference, and for appropriate approaches to reducing inequities. Transcripts were simultaneously translated and written in English and thematic analysis was conducted. An infoposter was identified as a feasible educational tool and was co-designed by researchers and community partners.

RESULTS

Participants identified patrilocality (ie, married sons reside with parents, married daughters with in-laws) and patrilineality (ie, sons inherit assets, daughters' husband receives a dowry) as structural precursors to proximal drivers (ie, old-age security) of son preference. Mothers' and grandmothers' value to their families depended strongly on having a son but did not guarantee security. Pressures (ie, internalised discrimination, reproductive coercion) to conceive a son were common after the birth of at least one daughter in the absence of sons. Participants did not know anyone who had a sex selective abortion in Canada; however, traditional sex selection methods (eg, herbal medicines) were mentioned. Our co-designed infoposter entitled 'Truths About Son Preference' addressed three misconceptions identified in discussions.

CONCLUSION

This study may be useful to health and social care providers in providing structurally competent and culturally humble counselling and care, particularly after the birth of daughters in the absence of sons. Community engagement is necessary for future intervention development.

Sex ratios at birth in Australia according to mother's country of birth: A national study of all 5 614 847 reported live births 1997-2016

Objectives

Son preference and sex selective practices have resulted in a deficit of girls in several countries, primarily across Asia. Emerging evidence indicates that son preference survives migration to Western high-income countries. The objective of this study was to assess male-to-female (M/F) ratios at birth per mother’s country of birth in Australia 1997–2016, in total and by parity, and by states/territories and over time.

Methods

Data for this national population-based cross-sectional study were obtained from the National Perinatal Data Collection (NPDC) and included all live births in Australia 1997–2016 (N = 5 614 847). M/F ratios with 95% Confidence Intervals were estimated.

Results

The M/F ratio for births to Australian-born mothers was within the expected range (1.03–1.07) regardless of parity and time period. M/F ratios were elevated above the expected range for births to mothers born in China in the total sample (M/F ratio 1.084, 95% confidence interval 1.071–1.097) and at parity 2 (1.175, 1.120–1.231), and for births to mothers born in India at parity 2 (1.146, 1.090–1.204). Parity 2 births were the most consistently male-biased across time. Across states, elevated M/F ratios were identified for both groups in New South Wales (China parity 2: 1.182, 1.108–1.260; India parity 2: 1.182, 1.088–1.285), for births to Chinese-born mothers in Victoria (total births: 1.097, 1.072–1.123; parity 1: 1.115, 1.072–1.159) and Australian Capital Territory (total births: 1.189, 1.085–1.302) and births to Indian-born mothers Western Australia (parity 2: 1.307, 1.122–1.523).

Conclusions

Son preference persists in some immigrant communities after migration to Australia. The consistent pattern of elevated M/F ratios across the larger states indicates that sex imbalances at birth are largely independent of restrictiveness of local abortion laws. Drivers and consequences of son preference in Western high-income settings should be explored to further promote gender equality, and to strengthen support for women who may be vulnerable to reproductive coercion.

Incidence of Pregnancy-Associated Cancer in Two Canadian Provinces: A Population-Based Study

Pregnancy-associated cancer—that is diagnosed in pregnancy or within 365 days after delivery—is increasingly common as cancer therapy evolves and survivorship increases. This study assessed the incidence and temporal trends of pregnancy-associated cancer in Alberta and Ontario—together accounting for 50% of Canada’s entire population. Linked data from the two provincial cancer registries and health administrative data were used to ascertain new diagnoses of cancer, livebirths, stillbirths and induced abortions among women aged 18–50 years, from 2003 to 2015. The annual crude incidence rate (IR) was calculated as the number of women with a pregnancy-associated cancer per 100,000 deliveries. A nonparametric test for trend assessed for any temporal trends. In Alberta, the crude IR of pregnancy-associated cancer was 156.2 per 100,000 deliveries (95% CI 145.8–166.7), and in Ontario, the IR was 149.4 per 100,000 deliveries (95% CI 143.3–155.4). While no statistically significant temporal trend in the IR of pregnancy-associated cancer was seen in Alberta, there was a rise in Ontario (p = 0.01). Pregnancy-associated cancer is common enough to warrant more detailed research on maternal, pregnancy and child outcomes, especially as cancer therapies continue to evolve.

Induced abortion according to immigrants' birthplace: a population-based cohort study

BACKGROUND

Most abortions occur due to unintended pregnancy. Unintended pregnancies are linked to poor health outcomes. Canada receives immigrants from countries with disparate sexual and reproductive health contexts which may influence abortion rates post-migration. We examined the association between abortion and region of birth and birth order among Canadian immigrants.

METHODS

We conducted a population-based person-years (PY) cohort study in Ontario, Canada using administrative immigration (1991-2012) and health care data (1991-2013). Associations between induced abortion and an immigrant's region of birth were estimated using poisson regression. Rate ratios were adjusted for age, landing year, education, neighborhood income quintile and refugee status and stratified by birth order within regions.

RESULTS

Immigrants born in almost all world regions (N = 846,444) were 2-5 times more likely to have an induced abortion vs. those born in the US/Northern & Western Europe/Australia & New Zealand (0.92 per 100 PY, 95% CI 0.89-0.95). Caribbean (Adjusted Rate Ratio [ARR] = 4.71, 95% CI 4.55-4.87), West/Middle/East African (ARR = 3.38, 95% CI 3.26-3.50) and South American (ARR = 3.20, 95% CI 3.09-3.32) immigrants were most likely to have an abortion. Most immigrants were less likely to have an abortion after vs. prior to their 1st birth, except South Asian immigrants (RR = 1.60, 95% CI 1.54-1.66; RR = 2.23, 95% CI 2.12-2.36 for 2nd and 3rd vs 1st birth, respectively). Secondary analyses included further stratifying regional models by year, age, education, income quintile and refugee status.

CONCLUSIONS

Induced abortion varies considerably by both region of birth and birth order among immigrants in Ontario.

Receipt of routine preventive care among infant daughters and sons of immigrant mothers in Ontario, Canada: a retrospective cohort study

OBJECTIVES

To explore gender disparities in infant routine preventive care across maternal countries of birth (MCOB) and by mother tongue among infants of Indian-born mothers.

SETTING

Retrospective population-based administrative cohort in Ontario, Canada (births between 2002 and 2014).

PARTICIPANTS

350 366 (inclusive) healthy term singletons belonging to families with a minimum of one opposite gender child.

OUTCOME MEASURES

Fixed effects conditional logistic regression generated adjusted ORs (aORs) for a daughter being underimmunised and having an inadequate number of well-child visits compared with her brother, stratified by MCOB. Moderation by maternal mother tongue was assessed among children to Indian-born mothers.

RESULTS

Underimmunisation and inadequate well-child visits were common among both boys and girls, ranging from 26.5% to 58.2% (underimmunisation) and 10.5% to 47.8% (inadequate well-child visits). depending on the maternal birthplace. Girls whose mothers were born in India had 1.19 times (95% CI 1.07 to 1.33) the adjusted odds of inadequate well-child visits versus their brothers. This association was only observed among the Punjabi mother tongue subgroup (aOR: 1.26, 95% CI 1.08 to 1.47). In the Hindi mother tongue subgroup, girls had lower odds of underimmunisation than their brothers (aOR: 0.73, 95% CI 0.54 to 0.98).

CONCLUSIONS

Gender equity in routine preventive healthcare is mostly achieved among children of immigrants. However, daughters of Indian-born mothers whose mother tongue is Punjabi, appear to be at a disadvantage for well-child visits compared with their brothers. This suggests son preference may persist beyond the family planning stage among some Indian immigrants.

Differences in Early Childhood Maltreatment by Maternal Birthplace and Child Sex

OBJECTIVE

To identify patterns of health system-identified early childhood maltreatment by maternal birthplace and child sex, within a multicultural society with universal access to healthcare.

STUDY DESIGN

This retrospective population-based cohort study included 1240946 children born in Ontario, Canada, between 2002 and 2012, and followed from birth to age 5 years using administrative data. Modified Poisson regression was used to estimate adjusted rate ratios for maltreatment-physical abuse or neglect-among the children of immigrant vs nonimmigrant mothers. Conditional logistic regression was used to estimate further the odds of maltreatment comparing a daughter vs son of the same mother.

RESULTS

Maltreatment rates were 36% lower (adjusted rate ratio, 0.64; 95% CI, 0.61-0.66) among children of immigrant mothers (10 per 1000) than those of nonimmigrant mothers (16 per 1000). Maltreatment rates were 27%-48% lower among children of maternal immigrant groups relative to that among Canadian-born mothers, except children of Caribbean-born mothers (16 per 1000). No significant differences were seen between daughters and sons in the odds of early childhood health system-identified maltreatment by maternal birthplace.

CONCLUSIONS

Health system-identified maltreatment in early childhood is highest among children of Canadian- and Caribbean-born mothers. Maltreatment did not differ between daughters and sons of the same mother. These data may inform strategies aimed at decreasing maltreatment among vulnerable groups.

Sex selection and non-invasive prenatal testing: A review of current practices, evidence, and ethical issues

Non-invasive prenatal testing (NIPT) can determine the sex of the fetus very accurately and very early in gestation. There are concerns that the ease, timing, and accuracy of NIPT sex determination will facilitate sex-selective termination of pregnancy (TOP). Here, we review current practices, the evidence for a link between NIPT and sex-selective TOP, and associated ethical issues. Sex-selective TOP, usually motivated by son preference, has had serious demographic consequences in countries such as India and China. Currently, ultrasound is the primary method by which parents determine the sex of the fetus. The diffusion of ultrasound technology has had a direct impact on the rates of sex-selective TOP. Although NIPT is currently more costly, it is feasible that increased uptake of this technology could have a similar effect. Partly because NIPT is a relatively recent development in prenatal screening, there is little data on the impact of NIPT on sex selection practices. Evidence that NIPT is playing a role in sex-selective TOP remains largely anecdotal. Further research is required to assess and quantify TOP resulting from NIPT sex determination. The use of these technologies for sex selection raises a number of ethical issues, in addition to practical demographic consequences.

A population-based study of the frequency and predictors of induced abortion among women with schizophrenia

BACKGROUND

Induced abortion is an indicator of access to, and quality of reproductive healthcare, but rates are relatively unknown in women with schizophrenia.

AIMS

We examined whether women with schizophrenia experience increased induced abortion compared with those without schizophrenia, and identified factors associated with induced abortion risk.

METHOD

In a population-based, repeated cross-sectional study (2011-2013), we compared women with and without schizophrenia in Ontario, Canada on rates of induced abortions per 1000 women and per 1000 live births. We then followed a longitudinal cohort of women with schizophrenia aged 15-44 years (n = 11 149) from 2011, using modified Poisson regression to identify risk factors for induced abortion.

RESULTS

Women with schizophrenia had higher abortion rates than those without schizophrenia in all years (15.5-17.5 v. 12.8-13.6 per 1000 women; largest rate ratio, 1.33; 95% CI 1.16-1.54). They also had higher abortion ratios (592-736 v. 321-341 per 1000 live births; largest rate ratio, 2.25; 95% CI 1.96-2.59). Younger age (<25 years; adjusted relative risk (aRR), 1.84; 95% CI 1.39-2.44), multiparity (aRR 2.17, 95% CI 1.66-2.83), comorbid non-psychotic mental illness (aRR 2.15, 95% CI 1.34-3.46) and substance misuse disorders (aRR 1.85, 95% CI 1.47-2.34) were associated with increased abortion risk.

CONCLUSIONS

These results demonstrate vulnerability related to reproductive healthcare for women with schizophrenia. Evidence-based interventions to support optimal sexual health, particularly in young women, those with psychiatric and addiction comorbidity, and women who have already had a child, are warranted.

Male-biased sex ratios in Australian migrant populations: a population-based study of 1 191 250 births 1999-2015

Background

The naturally occurring male-to-female (M/F) ratio at birth is 1.05. Higher ratios found primarily in countries across Asia have been attributed to prenatal sex selection due to son preference. There is growing evidence that sex-selective practices continue following migration; however, little is known about these practices following migration to Australia.

Methods

In this population-based study we assessed M/F ratios at birth per mother’s country of birth for all registered births 1999–2015 in Victoria, Australia (n = 1 191 250). We also compared the M/F ratio among births to mothers born elsewhere to that of mothers born in Australia, stratified by time period and parity.

Results

Compared with the naturally occurring M/F ratio as well as to the M/F ratio among births to mothers born in Australia, there was an increased ratio of male births to mothers born in India, China and South-East Asia, particularly at higher parities and in more recent time periods (elevated M/F ratios ranged from 1·079 to 1·248, relative risks of male birth ranged from 1·012 to 1·084 with confidence intervals between 1·001 and 1·160 and P-values between 0·005 and 0·039). The most male-biased sex ratios were found among multiple births to Indian-born mothers, and parity of two or more births to Indian and Chinese-born mothers in 2011–15.

Conclusions

The male-biased sex ratios observed in this study indicate that prenatal sex selection may be continuing following migration to Australia from countries where these practices have been documented. The excess of males among multiple births raises the question as to what role assisted reproduction plays. Findings also suggest that systematic discrimination against females starts in the womb.

Missing girls among deliveries from Indian and Chinese mothers in Spain 2007-2015

Deliveries from Indian and Chinese mothers present a higher than expected male:female ratio in their own countries, in northern Europe, EEUU and Canada. No studies have been carried out in southern European countries. We explored whether the high male-to-female ratio common in Indian and Chinese communities, also exists among families from those regions who live in Spain. For that purpose we designed a cross-sectional population-based study containing data on 3,133,908 singleton live births registered in the Spanish Vital Statistics Registry during the period 2007-2015. The ratio of male:female births by area of origin was calculated using binary intercept-only logistic regression models without reference category for the whole sample of births and taking into account a possible effect modification of birth order and sex of the previous males. Interaction effects of sociodemographic mothers' and fathers' characteristics was also assesed. In Spain, the ratio male:female is higher than expected for Indian-born mothers, especially for deliveries from mothers with no previous male births and, to a lesser extent, for Chinese-born women, specifically for third or higher order births and slightly influenced by the sex of the previous births. Therefore, the increased sex male:female ratio observed in other countries among Indian and Chinese mothers is also observed in Spain. This reinforces the notion that culture and values of the country of origin are more influential than the country of residence.

Intergenerational abortion tendency between mothers and teenage daughters: a population-based cohort study

BACKGROUND

A teenage woman's sexual health practices may be influenced by her mother's experience. We evaluated whether there is an intergenerational tendency for induced abortion between mothers and their teenage daughters.

METHODS

We conducted a retrospective population-based cohort study involving daughters born in Ontario between 1992 and 1999. We evaluated the daughters' data for induced abortions between age 12 years and their 20th birthday. We assessed each mother's history of induced abortion for the period from 4 years before her daughter's birth to 12 years after (i.e., when her daughter turned 12 years of age). We used Cox proportional hazard models to estimate a daughter's risk of having an induced abortion in relation to the mother's history of the same procedure. We adjusted hazard ratios (HRs) for maternal age and world region of origin, mental or physical health problems in the daughter, mother- daughter cohabitation, neighbourhood-level rate of teen induced abortion, rural or urban residence, and income quintile.

RESULTS

A total of 431 623 daughters were included in the analysis. The cumulative probability of teen induced abortion was 10.1% (95% confidence interval [CI] 9.8%-10.4%) among daughters whose mother had an induced abortion, and 4.2% (95% CI 4.1%-4.3%) among daughters whose mother had no induced abortion, for an adjusted HR of 1.94 (95% CI 1.86-2.01). The adjusted HR of a teenaged daughter having an induced abortion in relation to number of maternal induced abortions was 1.77 (95% CI 1.69-1.85) with 1 maternal abortion, 2.04 (95% CI 1.91-2.18) with 2 maternal abortions, 2.39 (95% CI 2.19-2.62) with 3 maternal abortions and 2.54 (95% CI 2.33-2.77) with 4 or more maternal abortions, relative to none.

INTERPRETATION

We found that the risk of teen induced abortion was higher among daughters whose mother had had an induced abortion. Future research should explore the mechanisms for intergenerational induced abortion.

Determinants of imbalanced sex ratio at birth in Nepal: evidence from secondary analysis of a large hospital-based study and nationally-representative survey data

OBJECTIVES

To quantify sex ratios at births (SRBs) in hospital deliveries in Nepal, and understand the socio-demographic correlates of skewed SRB. Skewed SRBs in hospitals could be explained by sex selective abortion, and/or by decision to have a son delivered in a hospital-increased in -utero investments for male fetus. We use data on ultrasound use to quantify links between prenatal knowledge of sex, parity and skewed SRBs.

DESIGN

Secondary analysis of: (1) de-identified data from a randomizedrandomised controlled trial, and (2) 2011 Nepal Demographic and Health Survey (NDHS).

SETTING

Nepal.

PARTICIPANTS

(1) 75 428 women who gave birth in study hospitals, (2) NDHS: 12 674 women aged 15-49 years.

OUTCOME MEASURES

SRB, and conditional SRB of a second child given first born male or female were calculated.

RESULTS

Using data from 75 428 women who gave birth in six tertiary hospitals in Nepal between September 2015 and March 2017, we report skewed SRBs in these hospitals, with some hospitals registering deliveries of 121 male births per 100 female births. We find that a nationally representative survey (2011 NDHS) reveals no difference in the number of hospital delivery of male and female babies. Additionally, we find that: (1) estimated SRB of second-order births conditional on the first being a girl is significantly higher than the biological SRB in our study and (2) multiparous women are more likely to have prenatal knowledge of the sex of their fetus and to have male births than primiparous women with the differences increasing with increasing levels of education.

CONCLUSIONS

Our analysis supports sex-selective abortion as the dominant cause of skewed SRBs in study hospitals. Comprehensive national policies that not only plan and enforce regulations against gender-biased abortions and, but also ameliorate the marginalizedmarginalised status of women in Nepal are urgently required to change this alarming manifestation of son preference.

TRIAL REGISTRATION NUMBER

NCT02718222.

Sex ratios at birth among second-generation mothers of South Asian ethnicity in Ontario, Canada: a retrospective population-based cohort study

Background

Son-biased sex ratios at birth (M:F), an extreme manifestation of son preference, are predominately found in East and South Asia. Studies have examined sex ratios among first-generation migrants from these regions, but few have examined second-generation descendants. Our objective was to determine whether son-biased sex ratios persist among second-generation mothers with South Asian ethnicity in Ontario, Canada.

Methodology

A surname algorithm identified a population-based cohort of mothers with South Asian ethnicity who gave birth in Ontario between 1993 and 2014 (n=59 659). Linking to official immigration data identified births to first-generation mothers (ie, immigrants). Births not to immigrants were designated as being to second-generation mothers (ie, born in Canada) (n=10 273). Sex ratios and 95% CI were stratified by the sex of previous live births and by whether it was preceded by ≥1 abortion for both first-generation and second-generation mothers.

Results

Among mothers with two previous daughters and at least one prior abortion since the second birth, both second-generation mothers and first-generation mothers had elevated sex ratios at the third birth (2.80 (95% CI 1.36 to 5.76) and 2.46 (95% CI 1.93 to 3.12), respectively). However, among mothers with no prior abortion, second-generation mothers had a normal sex ratio, while first-generation mothers gave birth to 142 boys for every 100 girls (95% CI 125 to 162 boys for every 100 girls).

Conclusion

Son preference persists among second-generation mothers of South Asian ethnicity. Culturally sensitive and community-driven gender equity interventions are needed.

Interventions to reduce adverse health outcomes resulting from manifestations of gender bias amongst immigrant populations: a scoping review

BACKGROUND

Immigrants to Western countries increasingly originate from countries with pervasive gender inequalities, where women experience disproportionately high rates of threats to their well-being. Health and social services in countries of settlement encounter several adverse outcomes linked to gender bias among immigrant groups. Little is known about interventions implemented to address manifestations of gender bias among immigrant populations.

METHODS

A scoping review was undertaken to describe the literature on existing interventions and determine knowledge gaps. Nine academic and grey literature databases were searched for literature, with four reviewers screening the results.

RESULTS

Of the 29 included reports, most targeted domestic violence amongst the Latino population in the United States, with few interventions focusing on other outcomes, populations, and settings. The majority reported achieving their objective, although 13 interventions were not evaluated.

CONCLUSIONS

Future research and practice to address gender bias among immigrants may benefit from expanding on ethnic diversity, designing and reporting evaluations, addressing the context of gender inequities, tailoring to local community needs, and engaging community-based groups.

Further evidence of male offspring preference for certain subgroups in the United States (2007-2015)

INTRODUCTION

Males are born in excess of females. This ratio (M/T=male/total births) is influenced by various factors. A recent study showed that M/T in the United States (US) is Asian or Pacific Islander>White>American Indian or Alaska Native>Black or African American. This study was carried out in order to ascertain whether there are M/T differences in different races in the US by birth order.

METHODS

Monthly male and female live births by race and birth order for the entire US were obtained for 2007-2015 with birth order as 1-≥6 for these races.

RESULTS

There were 36,499,163 births. M/T decreased with increasing sibling order for all races (p<0.0001) except for Asian or Pacific Islander births where M/T rose progressively to 3rd order births (p<0.0001) then fell (p=0.0002). Weighted mean maternal age for each birth order by race order was Asian or Pacific Islander>White Black or African American/American Indian or Alaska Native. The differences between adjacent means were all significant (almost all p<0.0001). The mean maternal age spread followed the same order.

DISCUSSION

Asians favour male offspring. This group may be systematically implementing foetal sex-specific feticide and/or implementing a Type1 stopping rule when a male birth is achieved in order to maximise male births. The potential putative effect of increasing maternal age to decrease M/T is not only excluded in this race, but goes contrary to the findings of this study insofar as Asian or Pacific Islander births have the oldest mean maternal ages. Son preference strongly persists in the US.

Sex Ratios at Birth Among Indian Immigrant Subgroups According to Time Spent in Canada

OBJECTIVES

To examine whether son-biased male to female (M:F) ratios at birth among linguistically different subgroups of Indian immigrants vary according to duration of residence in Canada.

METHODS

We analyzed a retrospective cohort of 46 834 live births to Indian-born mothers who gave birth in Canada between 1993 and 2014. The M:F ratio at birth was calculated according to the sex of previous live births and stratified by (1) time since immigration to Canada (<10 and ≥10 years) and (2) mother tongue (Punjabi, Gujarati, Hindi, and other). We estimated adjusted odds ratios (aORs) using multivariate logistic regression to assess the probability of having a male newborn with 5-year increases in duration of residence in Canada for each language group. ORs were adjusted for married status, knowledge of English/French, maternal education at arrival and age and neighbourhood income at delivery.

RESULTS

Among all Indian immigrant women with two previous daughters, M:F ratios were higher than expected (1.92, 95% CI 1.73-2.12), particularly among those whose mother tongue was Punjabi (n = 25 287) (2.40, 95% CI 2.11-2.72) and Hindi (n = 7752) (1.63, 95% CI 1.05-2.52). M:F ratios did not diminish with longer duration in Canada (Punjabi 5-year aOR 1.03, 95% CI 0.81-1.31; Hindi 5-year aOR 0.94, 95% CI 0.42-2.17).

CONCLUSION

Among the Punjabi and Hindi women with two previous daughters, longer duration of residence did not attenuate son-biased M:F ratios at the third birth. Gender equity promotion may focus on Punjabi- and Hindi-speaking Indian immigrant women regardless of how long they have lived in Canada.

Variations in male-female infant ratios among births to Canadian- and Indian-born mothers, 1990-2011: a population-based register study

BACKGROUND

We assessed variations in the male-female infant ratios among births to Canadian-born and Indian-born mothers according to year of birth, province and country of birth of each parent.

METHODS

In this population-based register study, we analyzed birth certificates of 5 853 970 singleton live births to Canadian-born and 177 990 singleton live births to Indian-born mothers giving birth in Canada from 1990 to 2011. Male-female ratios were stratified by live birth order and plotted by year of birth. Logistic regression was used to assess whether ratios varied between Canadian provinces and according to the birthplace of each parent. The deficit in the number of girls was estimated using bootstrap methods.

RESULTS

Among Canadian-born mothers, male-female ratios were about 1.05, with negligible fluctuations by birth order, year and province. Among Indian-born mothers, the overall male-female ratio at the third birth was 1.38 (95% confidence interval [CI] 1.34-1.41) and was 1.66 (95% CI 1.56-1.76) at the fourth or higher-order births. There was little variability in the ratios between provinces. Couples involving at least 1 Indian-born parent had higher than expected male-female ratios at the second and higher-order births, particularly when the father was Indian-born. The deficit in the expected number of girls among Indian immigrants to Canada in the study period was estimated to be 4472 (95% CI 3211-5921).

INTERPRETATION

Fewer than expected girls at the third and higher-order births have been born to Indian immigrants across Canada since 1990. This trend was also seen among couples of mixed nativity, including those involving a Canadian-born mother and an Indian-born father. Fathers should be considered when investigating sex ratios at birth.