I'm 31 weeks, and went for my check up yesterday. The doctor has picked up that my placenta has started to calcify, which should only begin from 36 weeks onward. She said that it may be due to secondary smoke inhalation, which I very rarely am in the company of a smoker (my dad). She said I should not be concerned but she wants to see me in 3 weeks time, instead of the normal 4 week check up. Baby is growing well, weighing 1.4 kg's. Has anyone heard of this before, if so, is it something I should stress about? I'm so worried since I left her office yesterday.