A study by McGready et al (2001) examined the effect of 20% solution of DEET applied by women during the 2nd and 3rd trimester. It was found that DEET was well accepted and had no adverse effects in women. There was no increase in low birth weight, prematurity or congenital abnormality. DEET does cross placenta (8% of cord samples), although blood levels were low. More information is needed on the safety of DEET in the 1st trimester.