FACTORS ADVERSELY ASSOCIATED WITH BREAST-FEEDING IN NEW-ZEALAND

Control data from 1529 infants studied in a multicentre case-control s tudy of sudden infant death in New Zealand were analysed to identify f actors that might hinder the establishment and duration of breast feed ing. Although 1300 infants (85%) were exclusively breast-fed at discha rge from the obstetric hospital, this fell to 940 (61%) by 4 weeks. Lo gistic regression was used to identify factors that might adversely in fluence breast feeding 'at discharge', 'at 4 weeks' and the overall 'd uration' of breast feeding. When adjusted for confounding factors, not exclusive breast feeding 'at discharge' was significantly associated with: twin pregnancy, being a Pacific Islander, mother not bedsharing, subsequent dummy use, birthweight less than 2500 g, heavy maternal sm oking, not attending antenatal classes and mother less than 20 years o ld at first pregnancy. Mothers smoking more than 20 cigarettes a day w ere nearly twice as likely to not exclusively breast feed on discharge compared to those who did not smoke. A 'dose response' was apparent w ith the heaviest smokers having the least likelihood of establishing e xclusive breast feeding. Being exclusively breast-fed at discharge but not 'at 4 weeks' was associated with: twin pregnancy, admission to a neonatal intensive care unit, subsequent dummy use and not being marri ed. A shorter overall 'duration' of breast feeding was associated with maternal smoking, subsequent dummy use, mother not bedsharing, twin p regnancy, mother less than 20 years old at first pregnancy, low occupa tional status and not attending antenatal classes. These effects persi sted when social and demographic factors, including birthweight, were taken into account. This study showed that 31% of New Zealand women ha d smoked during their pregnancy. A concerted effort to achieve smokefr ee pregnancies would not only directly improve the health of mother an d child but may enhance both the initiation and duration of breast fee ding. The influence on the duration of breast feeding of both dummy us age and the mother sharing the bed with her infant needs to be explore d further, as a causal relationship cannot be established from these d ata.