Objective Higher rates of neonatal morbidity and mortality at term combined with earlier spontaneous delivery have led to the hypothesis that babies born to South Asian born (SA-born) women may mature earlier and/or their placental function decreases earlier than babies born to Australian and New Zealand born (Aus/NZ-born) women. Whether babies born to SA-born women do better in the preterm period, however, has yet to be evaluated. In this study we investigated respiratory outcomes, indicative of functional maturity, of preterm babies born to SA-born women compared with those of Aus/NZ-born women to explore this hypothesis further.

Study design and setting This retrospective cohort study was conducted at Monash Health.

Patients Data were collected from neonatal and birth records of moderate-late preterm (32–36 weeks) infants born between 2012 and 2015 to SA-born and Aus/NZ-born women.

Outcome measures Rates of nursery admissions and neonatal respiratory outcomes were compared.

Results Babies born to Aus/NZ-born women were more likely to be admitted to a nursery (80%) compared with SA-born babies (72%, p=0.004). Babies born to SA-born mothers experienced significantly less hyaline membrane disease (7.8%), required less resuscitation at birth (28.6%) and were less likely to require ventilation (20%) than babies born to Aus/NZ-born mothers (18%, 42.2%, 34.6%; p<0.001). There was no difference in the duration of ventilation or length of stay in hospital.

Conclusions Moderate-late preterm babies born to SA-born women appear to have earlier functional maturity, as indicated by respiratory outcomes, than Aus/NZ-born babies. Our findings support the hypothesis of earlier fetal maturation in SA-born women.