Fulcheri and associates report that 1 of 10 pregnancies with an IUD in place resulted in a newborn with a major lip defect [letter]

Fulcheri and associates report that 1 of 10 pregnancies with an IUD in place resulted in a newborn with a major lip defect. The authors conclude that “. . . although pregnancies with IUD are exceptional it seems that fetal abnormalities are not”. This conclusion is not justified either by this one case or by the existing literature. The exact binomial 95% confidence interval around this proportion (1 of 10 or 10.0%) extends from 0.3% to 44.5%. Thus the true proportion of abnormal newborns in Fulcheri and associates’ study population probably falls between 3 and 445 per 1000. This range overlaps the background rate of birth defects in newborns. (excerpt)