There are certain factors that put an expectant mother at a risk of miscarriage and preterm labour maternal age cervical incompetence infections etc. Usually you don t have control over most of the things there are certain things that you do (albeit unknowingly) which increases your risk by manifold. Here are a few of them. Smoking: When you smoke you inhale around 4000 odd chemicals. However with every puff the nicotine and carbon monoxide that gets inside your body causes the maximum damage. Nicotine narrows the blood vessels in your body including the ones in the umbilical cord responsible for