What past medical history should alert the nurse that a client is at risk for a spontaneous abortion?

A history of syphilis can indicate an increased risk for spontaneous abortion due to the potential complications that arise from this sexually transmitted infection. Syphilis can lead to serious health issues during pregnancy, including affecting the placental function and leading to fetal distress or abnormalities. Furthermore, untreated syphilis can result in congenital syphilis, which can significantly impact the health and viability of the fetus. Bloodborne infections like syphilis have been associated with a higher incidence of miscarriage, particularly if the mother was infected during or just before pregnancy.

The other medical histories mentioned—recent weight loss, history of high blood pressure, and history of smoking—while they may pose risks in pregnancy, do not have as established a direct correlation to spontaneous abortion as a history of syphilis does. Weight loss can affect fertility and pregnancy outcomes, but it is not a specific indicator of miscarriage risk. High blood pressure may lead to complications such as preeclampsia but is not explicitly linked to spontaneous abortion. Smoking is known to have various adverse effects on pregnancy outcomes, including low birth weight and preterm birth, but the association with spontaneous abortion is less direct compared to the implications of a syphilis infection.