Deptt. of Community Medicine, J.N. Medical College, Belgaum
Research question: What is the prevalence of consanguineous marriages in a rural community and what is the effect of consanguinity on pregnancy outcome?
Objectives: To study (i) the prevalence and type of consanguinity and (ii) its effect on foetal loss, neonatal mortality, obstetric complications and congenital anomalies.
Study design: Cross-sectional
Setting: Shindoli village of District Belgaum.
Participants: 500 married women residing in the rural field practice area were interviewed.
Results: The prevalence of consanguinity was found to be 36%. Majority of the marriages were between first cousins (54.44%). Foetal loss was seen to be significantly higher in the consanguineous group as compared to non-consanguineous group (p<0.001). No significant effect of consanguinity was observed on the number of stillbirths, neonatal mortality, obstetrical complications and congenital malformations. Only 7.6% of the women were aware about the hazards of a consanguineous marriage.
Keywords: Consanguinity, Pregnancy outcome, Stillbirths, Neonatal deaths, Abortions
Marriage in Indian society is a religious duty. Consanguineous marriage is common, where individuals prefer to marry within their clan. Consanguineous unions range from cousin-cousin to more distant relatedness, and their prevalence varies by culture. Consanguinity has been known to increase the chance of the husband and wife carrying an identical gene derived from a common ancestor. Children of such a marriage, therefore, are at greater risk of being homozygous for a harmful gene and consequently suffer autosomal recessive genetic disorders1. Pregnancy wastage has also been found to be high for women marrying close relatives2.
The present study was conducted in Shindoli village of district Belgaum. All the married women residing in the village were included in the study, the number of whom was 500. A house to house visit was done, and the women were interviewed using a pre-designed proforma. Information regarding education, occupation, consanguinity and pregnancy outcome was collected. With regard to pregnancy outcome, a detailed history was obtained from the married woman about her past obstetrical record, which included history of abortions, obstetrical complications and still birth. History with regard to neonatal mortality and presence of congenital malformations in any of the children was also obtained.
Majority (55%) of women belonged to the age group between 15 to 30 years. Most of them (54.4%) were illiterate and the majority (74.4%) of them were housewives.
(N = 320)
(N = 180)
Of the 500 women, consanguinity was found in 36% of the marriages. Muslims had a higher frequency (39.4%) than Hindus (35.7%). However, this difference in the frequency was not statistically significant.
|First Cousin||Uncle - Niece||Others||Total|
Majority of the consanguineous marriage were between first cousins (54.44%). Uncle-niece marriages were present in 33.8% while 11.6% of the marriages were among those with more distant relationship.
(N = 180)
(N = 320)
|Still births||10||5.5%||15||4.6%||Z=0.5; p>0.05|
|Neonatal deaths||11||6.1%||10||3.1%||Z=1.76; p>0.05|
Foetal losses which occurred at or before 28 weeks of gestation were in 18.8% and 5% respectively in consanguineous and non-consanguineous groups. The value was found to be statistically significant (p<0.001). Still births were higher in consanguineous than in non-consanguineous group. There was no significant difference in the number of neonatal deaths between the consanguineous and nonconsanguineous groups.
Obstetric complications like PIH and antepartum haemorrhage were more among non-consanguineous (8.3% and 0.93%) as compared with consanguineous (7.18% and 0.55%). However, the difference was not statistically significant.
5(2.8%) congenital malformations were observed in consanguineous group and 4 (1.25%) in the nonconsanguineous group (p>0.05). The congenital malformations were - congenital cataract (n=2), bifid tongue (n=l), cyanotic heart disease (n=3), cleft palate (n=l), hydrocephalus (n=2).
Only 7.6% of the women were aware about the hazards of a consanguineous marriage.
The frequency of consanguinity in the present study was 36% which is less than that observed in other studies in South India3-5. This could be attributed to the increasing modernization due to which the chances of such marriages are on the decline. Muslims showed a higher frequency of consanguinity as compared to Hindus. This finding is in contrast to that found in other studies, wherein, consanguineous marriages were more among the Hindus3,6,8. The most frequent type of consanguineous marriage in our study was between first cousins (54.44%). This is comparable to the findings observed in other studies4,6,8. All the cousin marriages were between cross cousins. No parallel cousin marriages were observed. Foetal losses before 28th weeks were higher in consanguineous group as compared to nonconsanguineous group, and this difference was statistically significant. Most studies have demonstrated higher foetal losses among pregnancies in women who were married consanguineously3,9.
Our study, however, did not show a significant difference in the number of still births, neonatal deaths and congenital malformations between the consanguineous and non-consanguineous groups. Jain et al7 demonstrated that consanguinity had no significant effect on foetal losses but that the frequency of consanguinity was higher with congenital anomalies. Kulkarni et al10 found that congenital malformations and still birth rates were significantly higher in offspring born to mothers in consanguineous marriages.
Present study did not observe any effect of consanguinity on obstetric complications such as PIH. This finding is similar to that observed by George K. et al in their study on the aetiology of PIH11.
The sample size in the present study was not sufficiently large to study the effect of consanguinity on the stillbirth rate, neonatal mortality and incidence of congenital malformations and genetic disorders.
The awareness with regard to the hazards of consanguineous marriages was very low (7.6%). Hence, this study suggests that steps should be taken to inform people about the problems of marrying close relatives through appropriate IEC programmes. It would also be advisable to avoid consanguineous marriages in families where already a child with an autosomal recessive disorder has been born.