Consanguineous marriage and differentials in age at marriage, contraceptive use and fertility in Pakistan

J Biosoc Sci. 1999 Jan;31(1):121-38. doi: 10.1017/s0021932099001212.


Fertility rates in Pakistan have remained consistently high over the past three decades. While numerous studies have examined sociodemographic determinants, the role of biological factors, and particularly consanguinity, has received little attention, even though marriage between close biological relatives continues to be the norm in Pakistan. Reproductive behaviour among women in consanguineous (first cousin) and non-consanguineous unions was compared, using data from a 1995 study of multi-ethnic communities in Karachi and the 1990-91 Pakistan Demographic & Health Survey (PDHS). The results show that, although female age at first marriage has been gradually rising in both study samples, women in consanguineous unions married at younger ages and were less likely to use modern contraceptive methods. In the Karachi sample, women in first cousin unions experienced a higher mean number of pregnancies and also reported a higher mean number of children ever born (CEB). However, their mean number of surviving children did not differ from those born to women in non-consanguineous unions, implying higher prenatal and/or postnatal losses in couples related as first cousins. On the other hand, the PDHS showed both lower CEB values for women in consanguineous marriages and a lower number of surviving children. Given the continuing popularity of consanguineous marriage, these findings have important implications for future fertility reduction in Pakistan.

PIP: This study examined fertility among women in consanguineous unions (CUs) in Pakistan and the association between CUs and contraceptive use and marriage age. Macrolevel data were obtained from the 1990 Demographic and Health Survey (DHS) among a subset of 4679 ever-married women. Microlevel data were obtained from a 1995 survey (KS) among a subset of 913 current married women from 4 squatter settlements in Karachi. Marriage age (MA) was 17.4 years in the KS and 17.8 years in the DHS. MA increased from oldest to younger cohorts in both samples. Female education was associated with the increase in MA. Urdu speakers had a much higher MA. Women in CUs had lower MA among all ethnic groups. 49.3% in the KS and 8.8% in the DHS reported current contraceptive use. Contraceptive use in the DHS differed significantly by marriage duration, child survival, and child mortality. Logistic models reveal that women in CUs in the KS were less likely to use contraceptives, after controlling for education. Both samples showed that contraceptive use was related to sex composition of surviving children and ethnicity. Women with only daughters were least likely to use. Place of residence was the strongest predictor of ever use. Duration of marriage was a significant predictor only in the DHS. Women in first cousin CUs in the KS had a higher mean children ever born (CEB) and number of pregnancies; DHS findings were the reverse. Multiple classification analysis showed in the KS that when sociodemography was controlled, CU was unrelated to mean CEB. DHS data showed CUs associated with reduced fertility. In both samples, mortality of children aged under 10 years had the most significant effect on CEB.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Age Factors
  • Child
  • Consanguinity*
  • Contraception Behavior / statistics & numerical data*
  • Educational Status
  • Ethnicity
  • Female
  • Fertility*
  • Health Surveys
  • Humans
  • Logistic Models
  • Male
  • Pakistan / epidemiology
  • Parity
  • Pregnancy
  • Pregnancy Outcome