Working memory and low birth weight

Premature birth occurred in 14.9 million babies born in 2010, or in over 10% of the births worldwide and is defined as birth prior to 37 weeks (Blencowe et al., 2013). In 2013, 1.92 % preterm births were infants born fewer than 32 weeks gestation and 0.73% occurring prior to 28 weeks gestation (Rogers and Hintz, 2016). Viability, which is typically considered to be between 22 and 24 weeks gestation, can differ depending on the location of birth (i.e., country) and neonatal services available in that location (Marlow, Bennett, Draper, Hennessy, Morgan, and Costeloe, 2014). Over the last decade, survival rates of infants born preterm have increased substantially, particularly for children born earlier in gestation. For instance, survival rates of infants born at 23 weeks gestation have increased from 8% to 52% in Sweden in the most recent era (Fellman et al., 2010). Similarly, survival rates have increased to 63% survival in Japan (Ishi et al., 2013).