in early weeks of pregnancy
brownish discharge or little spotting can be seen because of many reasons among them serious one is impending miscarriage
for that as one of the preventive measures your doctor might have prescribed utrogestan
, which is a synthetic progesterone
this is considered as category B drug in pregnancy, means animal studies showed no adverse effects but sufficient studies lacking in animals and humans,
as such in general practice these will be prescribed usually.
so after discussing with your doctor if he says that benefits over weigh the risks then you can use those tablets.