Chapter 3, Problem 144P

Obstetrics, Health Promotion

A study was performed to assess the accuracy of self-reported exposure to cigarette smoking in-utero. A comparison was made between daughters’ reports of smoking by their mothers during pregnancy with the mother’s self-reports of their own smoking while pregnant with their daughters. The results were as shown in Table 3.23.

Table 3.23 Relationship between mothers’ self-reports of smoking while pregnant and daughters’ reports of fetal smoke exposure

which positive indicates smoking and negative indicates not smoking?

Additional data on self-reported smoking indicate that the mother is not always completely accurate. Saliva cotinine is a biochemical marker that, if elevated, is a 100% accurate indication of recent smoking.

Suppose if the mother states she is a nonsmoker during pregnancy that saliva cotinine is elevated 5% of the time, whereas if the mother states she is a smoker during pregnancy that saliva cotinine is elevated 97% of the time. Assume also that a daughter report adds no further information regarding the probability of an elevated cotinine level once the mother’s self-report is known.

What is the probability that the saliva cotinine level in the mother is not elevated during pregnancy if the daughter reports that the mother did not smoke in-utero?