Answer:
There is not such a thing as a QRS wave and it is just another name for QRS complex which I'm sure you know represents ventricular polarization
Explanation:
The use of alcohol, tobacco and drugs can contribute to all of the following like, increased possibility of miscarriage, premature delivery, low birth weight except delayed labor. It is impossible that a mother can have delayed labor because first using this kind of drugs can give you miscarriage.
