Was the pharmacy a national chain, regional, local, or one-off?
In my experience in data exchanges with other large companies, data is usually shared and processed in batches where even an hour lag would be considered "very quick".
I don't know if you can say that for sure or not.
Regardless of whom shares customer data with whom, this whole issue has a number of legal/compliance issues beginning with HIPAA. The pregnancy test purchase, when anonymized, is just a sales data point, sure. When combined with identifying your girlfriend, and then giving that data to a third party (especially for non health-care treatment or paying claims needs), is most certainly illegal. If she had purchased a Coke, then no, but given she purchased a health-related product it falls into a myriad of laws that govern health care privacy.