ANTENATAL AND INTRAPARTUM FACTORS ASSOCIATED WITH SUDDEN-INFANT-DEATH-SYNDROME IN THE NEW-ZEALAND COT DEATH STUDY

Objective: To describe the relationship between antenatal and intrapar tum factors and sudden infant death syndrome (SIDS). Methodology: The New Zealand Cot Death Study was a 3 year case-control study, with 485 infants who died from SIDS in the postneonatal period and 1800 randoml y selected control infants. Data were obtained from obstetric records, parental interview and community nursing records. Results: This study confirms many of the antenatal and intrapartum risk factors for SIDS noted in studies from both the southern and northern hemispheres. Afte r controlling for potential confounders, such as occupational group an d marital status, significant inverse effects were noted for interpreg nancy interval, birthweight and gestation. Other factors that retained a significantly increased risk of SIDS were: increasing parity, bacte riological evidence of urinary tract infection (UTI) (adjusted odds ra tio 1.73, 95% Cl 1.10-2.73); smoking antenatally (AdjOR 2.14, 95% Cl 1 .61-2.84); less than six antenatal checks attended (AdjOR 1.84, 95% Cl 1.19-2.84); second stage of labour less than 16 min (AdjOR 2.06, 95% Cl 1.35-3.14) and multiple birth (AdjOR 3.23, 95% Cl 1.70-6.02). No in teraction was observed between maternal haemoglobin and antenatal smok ing. Interactions were tested for and not found between antenatal smok ing and three antenatal risk factors (UTI, short second stage of labou r and number of antenatal appointments). The only significant interact ion between these three factors and three modifiable postnatal risk fa ctors (prone sleeping, bed sharing and bottle feeding) was between bed sharing and fewer antenatal appointments. The risk of SIDS associated with bed sharing was greater among those whose mothers had fewer ante natal appointments. Conclusions: Although many of the previously ident ified antenatal and intrapartum risk factors for SIDS are confirmed, t he risks of SIDS associated with obstetric factors are in general cons iderably lower than the risks associated with the four modifiable post natal risk factors.