Risk factors for low birthweight in north-east Brazil: the role of caesarean section

Caesarean section (CS) delivery is associated with low birthweight (LBW) in south-east Brazil. A hospital-based study was conducted on singleton infan ts from mothers residing in Sao Luis, to assess if an association between C S and LBW was found in the northern part of the country, where the CS rate is lower than in the south-east. A standardised questionnaire was administe red to a sample of 2541 mothers in 10 hospitals, representing 94% of all de liveries, from March 1997 to February 1998. In a logistic model, type of de livery was the independent variable, the other variables were treated as co nfounders, and interaction terms were added between type of delivery and al l other factors. LBW was associated with low maternal height, maternal smok ing, primiparity, previous LBW, public insurance, preterm birth and CS. The CS rate was 33.7%. The risk of CS was higher for primiparous and married m others, those with high level of schooling and attended by the same physici an during prenatal and delivery care, deliveries held in private hospitals, daylight hours or evenings, and for those mothers who had adequate prenata l care. Because it appears unlikely that only medical reasons are operative , it is a possibility that CS could cause LBW, reflecting abusive indicatio ns for elective CS.