Placental insufficiency irrespective of offspring karyotype in maternal Turner syndrome: a case series and literature review

Turner syndrome is one of the most common aneuploidies. In vitro fertilization with oocyte donation is the usual method of assisted conception, but spontaneous pregnancy can also occur. Although pregnancies in Turner syndrome are widely accepted to be associated with small for gestational age foetuses, neither the causal role of placental insufficiency nor the contribution of maternal and foetal factors is well understood. Between 2009 and 2023, we followed 75 patients diagnosed with Turner syndrome at our university clinic, and four Turner syndrome patients became pregnant (4/75; 5.3%): ten pregnancies with seven live births (7/10; 70%) were reported. Conception was spontaneous in 6/7 patients (86%), and one patient had in vitro fertilization with oocyte donation. Two Turner syndrome patients with karyotype 45,X and two Turner syndrome patients with mosaicism (45,X/46,XX) were identified. Prenatal transabdominal amniocentesis revealed aneuploidy (45,X) in two foetuses. The most common obstetric complication was placental insufficiency, which presented as intrauterine growth restriction and foetal distress. Four early-term deliveries, one late-term delivery, one preterm delivery, and one extremely premature delivery occurred, and all pregnancies were terminated by caesarean section. No severe maternal complications during pregnancy were reported. Only newborns with Turner syndrome had long-term health problems. In Turner syndrome patients, even if pregnancy is conceived spontaneously, no maternal complications occur, and the foetus also has a normal karyotype, there is still a high prevalence of placental insufficiency and foetal compromise. The presented cases highlight the possible role of inherent maternal factors in Turner syndrome-associated intrauterine growth restriction and emphasize the importance of enhanced obstetric surveillance even in apparently uncomplicated Turner syndrome pregnancies.