stopping zyrtec for milk production

JM

with my first pregnancy my milk didn't come in until day 5 causing my baby to be hospitalized. on day 4 they told me to quit my zyrtec... I didn't know that would effect it. so now that I'm pregnant with #2 I'm wondering if I need to stop it before I give birth, or if I stop the day the baby is born it will be good enough? I really want breastfeeding to work this time!