Which factor is NOT associated with increased incidence of early onset GBS disease?

The factor that is associated with a decreased incidence of early onset Group B Streptococcus (GBS) disease is gestational age greater than 40 weeks. While it is widely recognized that early onset GBS disease is more common in infants born to mothers with risk factors such as low birth weight, high GBS inoculum, and intrapartum fever, gestational age greater than 40 weeks is typically not viewed as a risk factor for GBS disease.

Infants born before 37 weeks of gestation, particularly those born prematurely, have an underdeveloped immune system and are therefore more vulnerable to infections, including GBS. Similarly, mothers with a high inoculum of GBS or intrapartum fever are at increased risk of passing the infection to their newborns during delivery. In contrast, an extended gestational age often suggests maturation of the fetal immune system and could be related to a more favorable outcome regarding susceptibility to infections like GBS. Thus, gestational age greater than 40 weeks does not correlate with an increased incidence of early onset GBS disease and is the correct choice.