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

Fertility rates in Pakistan have remained consistently high over the past t hree decades. While numerous studies have examined sociodemographic determi nants, the role of biological factors, and particularly consanguinity, has received little attention, even though marriage between close biological re latives continues to be the norm in Pakistan. Reproductive behaviour among women in consanguineous (first cousin) and non-consanguineous unions was co mpared, using data from a 1995 study of multi-ethnic communities in Karachi and the 1990-91 Pakistan Demographic & Health Survey (PDHS). The results s how that, although female age at first marriage has been gradually rising i n both study samples, women in consanguineous unions married at younger age s and were less likely to use modern contraceptive methods. In the Karachi sample, women in first cousin unions experienced a higher mean number of pr egnancies and also reported a higher mean number of children ever born (CEB ). However, their mean number of surviving children did not differ from tho se 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 marriag es and a lower number of surviving children. Given the continuing popularit y of consanguineous marriage, these findings have important implications fo r future fertility reduction in Pakistan.