Hello Ashok, Welcome to Healthcare Magic forum. Lithosun sr contains lithium a mood stabiliser medication. Theoretically it can cause congenital heart disease in the fetus if taken during pregnancy. Lithium being associated with fetal heart risk and secreted in high levels in breast milk, is better avoided during pregnancy (particularly during first 3 months of pregnancy, a period when organs of the fetus are getting formed) and also during lactation. Guidelines suggest that mood stabilizers like Lithium should better be avoided. The guidelines also suggest that w.r.t pregnancy there is most experience with certain antidopaminergic drugs like trifluperazine, chlorpromazine, olanzapine which may be used instead.Overall, medicines should be avoided in the first trimester of pregnancy. But the challenge is to controll maternal illness along with minimal risk to developing fetus.So do discuss it with your obstetrician as well as psychiatrist . Prior to planning pregnancy, if a decision is arrived at in terms of stopping medication, then a careful taper is suggested rather than an abrupt withdrawal. Hope I have answered your query.