A qualitative study of parents' experiences with receiving a prenatal diagnosis of confined placental mosaicism – “We had nothing to rely on, you know?”

Prenatal detection of mosaicism in chorionic villus sampling (CVS) poses significant challenges for genetic counseling due to difficulties in predicting fetal involvement and clinical outcomes. Even when mosaicism is confined to the placenta (CPM), there remains an elevated risk of adverse outcomes, including preterm birth and low birth weight. These uncertainties regarding diagnosis and prognosis complicate clinical decision-making and may have a profound psychological impact on expectant parents. Thus, this qualitative study aimed to explore how parents experience the diagnosis and navigate pregnancy following a prenatal diagnosis of CPM. The study was conducted within Denmark's national healthcare system from January 2023 to November 2024. During this period, 14 semistructured interviews were carried out with 24 participants (10 joint interviews with both parents, four interviews with the mother only) who had received a prenatal CPM diagnosis and continued pregnancy. Interviews took place approximately 6 months after birth and were analyzed using thematic analysis. Uncertainty was central to parents' experiences of CPM, varying in intensity across individuals and over time. Three overarching themes were developed to explore this uncertainty: (1) Sources of uncertainty, included the complexity of mosaicism, probabilistic risk, and ambiguous information; (2) Impact of uncertainty, reflected fears about fetal health and emotional strain on parents; and (3) Managing uncertainty, involved both problem-focused strategies (e.g., information-seeking) and emotion-focused strategies (e.g., distancing, seeking support, and maintaining hope). Additionally, clear, empathetic communication from healthcare professionals supported parental coping, while ambiguous or inconsistent messaging intensified uncertainty. The birth of a healthy baby was a significant relief, though uncertainty and worry continued to linger for some. These findings highlighted the central role of uncertainty in parental experiences of CPM and can inform genetic counseling approaches to address this uncertainty and support adaptive coping throughout pregnancy.