Preterm birth tied to adverse sensory outcomes
Infants born preterm are at heightened risk of developing sensory disabilities, such as hearing loss and visual impairment, a study has found. Other risk factors include intracranial haemorrhage and convulsions.
Researchers looked at 1,018,256 infants delivered between 1991 and 2008 in Finland. Of these, 6,329 were born very preterm (VP; <32 weeks), 6,796 moderately preterm (MP; 32–33 weeks), 39,928 late preterm (LP; 34–36 weeks) and 965,203 at term (≥37 weeks).
Sensory impairments occurred with increasing frequency as gestational age at birth decreased (p<0.001). Hearing loss incidence was sevenfold greater in the VP group, more than twofold greater in the MP group and 1.5-fold greater in the LP group relative to the term group. Likewise, incidences of visual disturbances or blindness and other ophthalmologic disorders decreased with advancing gestational age at birth. Retinopathy of prematurity was presented commonly in the VP group of infants.
The risk of developing hearing loss increased by as much as twofold in VP (odds ratio [OR] 2.34; 95 percent CI, 1.75–3.14) and LP (OR, 1.26; 1.04–1.52) births. On the other hand, the risk of visual impairment was significantly elevated in all preterm birth categories: VP (OR 1.94; 1.55–2.44), MP (OR 1.42; 1.11–1.80) and LP (OR 1.31; 1.16–1.49).
Other significant factors associated with increased risks of hearing loss and visual impairment were intracranial haemorrhage (p<0.001 for both) and convulsions (p=0.009 and p<0.001, respectively).
According to researchers, MP and LP infants with known risk factors for sensory impairment should be referred for further evaluation in order to receive diagnosis and treatment as early as possible. Additionally, the adverse effects of smoking on the foetus should be mentioned in the counselling of pregnant women early in pregnancy.