Is Sadie pregnant?

She tells Kevin that she is and that that's why she stopped taking her medication, but she tells the police officers at the end she's not. Who was she lying to; Kevin or the police? If she lied to the police, then there should be a smaller chance of her repeating herself with the new boyfriend as she would be back on her medication again. If she lied to Kevin, then it would explain why she was doing things pregnant women should be doing like drinking alcohol and smoking.