Pregnant women, just like the rest of the population, are at risk of the novel A/H1N1 infection. However, since they belong to a more susceptible group of patients, the risk of a severe course of the disease is significantly higher when compared to their non-pregnant counterparts. This risk is especially great when the infection is accompanied by chronic conditions such as asthma or diabetes mellitus, resulting in an increased morbidity and mortality of both the mother and the fetus. Objectives: The aim of the study was to present the first four cases of A/H1N1 infection in advanced pregnancy in Podkarpacie Province of Poland that were noted in the course of six weeks in November and December 2009. Patients and Methods: Maternal age ranged between 27 to 34 years, gestational age was between 29 to 38 weeks. One patient had been at first admitted to Infectious Disease Clinic, and later on transferred to the Intensive Care Unit due to respiratory distress syndrome. The remaining three patients were hospitalized in the obstetrical unit, two of them due to respiratory tract infection and one due to amniotic fluid leakage without any respiratory failure symptoms. Three patients required artificial ventilation. One patient delivered vaginally, and the remaining three had caesarean section, one of them had an emergency c-section in agonia. The fatal outcome in this patient was the result of improper diagnosis due to a false negative stripe-test result. In case of the other three patients, properly diagnosed with Real Time RT-PCR test, an immediate antiviral therapy was introduced. Two neonates died: one delivered by the woman in agonia, and one due to intrauterine hypoxia and prematurity. Conclusions: Diagnostic and therapeutic difficulties in A/H1N1 infections in pregnant women may have their source in that fact that an unreliable stripe test alone is used (without confirmation of the infection with Real Time RT-PCR), risk factors are not taken into the account and antiviral therapy is delayed or postponed. Early antiviral therapy and delivery in case of respiratory distress syndrome improve the prognosis for both the mother and the child.