Share 'Tick control for pregnant & nursing bitches?'

The tick season has started early this year... I'd normally use the Scalibor tick collars for my dogs but this year, with my bitch Erin being in whelp, I am uncertain what to do. The vet says Frontline or Scalibor would be OK - but I hardly dare! On the other hand the risk of tick spread disease is real. I'd welcome your views...