It is unlikely that there is a single number associated with this phenomenon. Several studies have suggested that women who use cocaine are more likely to harm or neglect their child. It is important to note that, particularly during the 1980's, some states prosecuted woman for child abuse when they prenatally used cocaine, which could skew the results. If these cases were analyzed exclusively, the correlation would be 1, because every case of prenatal cocaine use would result in child abuse conviction.
However, this question refers to a specific study or book chapter, it is unlikely that a consensus correlation estimate is available. Such estimates should be evaluated with extreme caution, as this data is subject to numerous design errors and confounds.