Infection caused by human parvovirus B19 (B19) often has mild yet wide-ranging clinical signs, with the course of disease usually defined as benign. Particularly prevalent in the population of young children, the virus is commonly transmitted to the parents, especially to susceptible mothers. During pregnancy, particularly the first and second trimesters, parvovirus infection can lead to pathology of the fetus: anemia, heart failure, hydrops, and disorders of physical and neurological development. In severe cases, the disease can result in fetal demise. This article presents a rare case of manifestation of B19 infection during pregnancy. At the 27th week of gestation, a sudden change in fetal movement occurred in a previously healthy pregnancy. The examination of both fetus and the mother revealed newly formed fetal subdural hematoma of unknown etiology and ventriculomegaly. Following extensive examination to ascertain the origin of fetal pathology, a maternal B19 infection was detected. Due to worsening fetal condition, a planned cesarean section was performed to terminate the pregnancy at 31 weeks of gestation. A preterm male newborn was delivered in a critical condition with congenital B19 infection, hydrocephalus, and severe progressive encephalopathy. The manifestation and the origin of the fetal condition remain partially unclear. The transplacental transmission of maternal B19 infection to the fetus occurs in approximately 30% of cases. The main method for diagnosing B19 infection is Polymerase Chain Reaction (PCR) performed on blood serum. In the absence of clinical manifestations, the early diagnosis of B19 infection is rarely achieved. As a result, the disease left untreated can progress inconspicuously and cause serious complications. Treatment strategies are limited and depend on the condition of the pregnant woman and the fetus. When applicable, intrauterine blood transfusion reduces the risk of fetal mortality. It is crucial to assess the predisposing factors of the infection and evaluate signs of early manifestation, as this may help prevent the progression and poor outcomes of the disease.

Background/Objectives: A wide range of syphilis-related pregnancy complications are encountered in clinical practice. Active surveillance of the epidemiological situation in different countries and a series of retrospective data analyses allow for a comprehensive assessment of the feasible consequences of syphilis infection during pregnancy. The negative effects of infection on reproductive health are also described. Risk-increasing factors (inadequate or late treatment, partner coinfection) and protective factors (timely diagnostics and treatment) are distinguished. The importance of adequate and timely management as well as the accessibility of healthcare and socioeconomic status, which influence health outcomes, are stressed. This article presents a rare case of untreated syphilis infection during pregnancy. The infection was diagnosed during the first antenatal visit; how-ever, treatment was not initiated. At the 33rd week of gestation, the patient was admitted to the hospital because of sparse bloody vaginal discharge. Following sudden fetal hypoxia, an urgent cesarean section was performed at 33 weeks of gestation. A preterm newborn was delivered in critical condition, and congenital syphilis was diagnosed. Methods: We searched the PubMed, Cochrane, and MeSH databases using the key search terms “treponema pallidum”, “sexually transmitted infections”, “pregnancy”, “congenital infection”, “syphilis”, and “congenital syphilis”, as well as their combinations. A total of 28 papers published over a ten-year period were included in the literature review. A clinical case was analyzed. Results: The impact of syphilis on pregnancy is quite evident. Our case showcased one of the most common impacts, i.e., premature birth, of congenital infections with associated bacterial meningitis, respiratory distress syndrome, multiple organ damage, and insufficient weight. Such associations with many adverse pregnancy outcomes as well as congenital syphilis and neonatal defects are often avoidable. Conclusions: Considering the potential consequences of infections, the issue of sexually transmitted diseases remains relevant, and improving diagnostic and treatment opportunities becomes of paramount importance as cases increase.