A settlement has been reached in a lawsuit filed against a pharmaceutical company by a Watertown woman who linked her prescribed use of Paxil to the death of her infant son, according to court files. Jennifer Berg of Watertown sued SmithKline Beecham, doing business as GlaxoSmithKline, in October 2007. The complaint said Nathan Berg died in 2004 because of a heart disorder caused by her use of the antidepressant Paxil while she was pregnant.