I am pregnant but am used to smoking a package a day. Is this a problem?

Smoking during pregnancy increases the risk of premature delivery by 60% and of a spontaneous abortion. The weight at birth is often lower than average, making the child more liable to diseases. Of mothers who smoke more children die around the time of birth and the children have an increased risk of being hyperactive. There are some indications that smoking affects the IQ of the child and the motor system. To put it briefly: it’s irresponsible to keep smoking a package a day while you are pregnant.