Cumulative effect of consanguinity on prenatal mortalities among offspring in Northen Morocco

Abstract

Introduction: Consanguinity is defined as a union between two individuals related as first cousins, second cousins or even more distant unions. This behaviour will contribute to the impoverishment of genetic variability and will offer a possibility of prenatal mortality.

Objective: In this context, we suggest modelling the cumulative effect of consanguinity of maternal and paternal grandparents across that of parents among socio-demographic differences on prenatal mortality indicators in Tetouan (Morocco).

Methods: Data were collected on 882 couples in 2017. We conducted multivariable logistic regression analysis for factors associated with prenatal mortalities and then generated the average adjusted predictions and marginal effects.

Results: Multiple logistic regression analyses show that, for first cousin once removed and first cousin paternal grandparents, the odds in favour of prenatal mortalities among the student’s mother were 9.60 (aOR=9.60) and 3.90 (aOR=3.90) times greater than non-consanguineous, respectively, controlling for all other variables. Similarly, the odds in favour of prenatal mortalities among the offspring of these mothers was 3.62 (aOR=4.89) times greater when maternal grandparents were first cousins versus non-consanguineous. However, average adjusted predictions showed that when paternal grandparents were first cousins compared to non-consanguineous, and when paternal grandparents were first cousins once removed compared to non-consanguineous or second cousins, whatever the degree of parents’ consanguinity, the predicted probability of prenatal mortalities was higher than 20% and 30% (p≤0.05), respectively. Furthermore, for first cousin maternal grandparents compared to other degrees of consanguinity, concerning all degrees of parents’ consanguinity, the predicted probability of prenatal mortalities was between 20% and 48% (p≤0.05).

Conclusion: Accumulation of close biological relationships in several generations increases the probability of prenatal mortalities among offspring. A better understanding of the cumulative effect of consanguinity by socio-demographic factors can inform more-targeted interventions to reduce pregnancy wastage.