Background: Homocysteine (Hcy) plays a pivotal role in human reproduction, influencing gamete quality, embryo development, implantation, and pregnancy outcomes. It is central to folate and methionine metabolism and supports methylation-dependent epigenetic processes. Hyperhomocysteinemia (HHcy) exerts diverse biological effects and is associated with reproductive impairments in both sexes, affecting both spontaneous fertility and the outcome of assisted reproduction, including In Vitro Fertilization (IVF). Although the mechanisms of HHcy toxicity in reproduction are not fully understood, significant progress has been made in elucidating its effects. The emerging picture is complex, as Hcy and its metabolites impact biomolecules and cellular processes in a tissue- and sex-specific manner. Results: In men, HHcy compromises sperm deoxyribonucleic acid (DNA) integrity, methylation, and testicular microcirculation, reducing fertility potential. In women, HHcy disrupts follicular growth, oocyte competence, embryo quality, and endometrial receptivity, increasing the risk of implantation failure, miscarriage, and pregnancy complications. In assisted reproduction, HHcy and 5,10-methylenetetrahydrofolate reductase (MTHFR) variants may lower oocyte yield and embryo quality, although folate and B-vitamin supplementation can mitigate these effects. Conclusions: These effects largely reflect oxidative, inflammatory, vascular and epigenetic mechanisms, highlighting Hcy as a modifiable factor for improving natural fertility, optimizing IVF outcomes, and supporting healthy offspring development.

Background: Vitamin D deficiency is associated with several obstetric complications in singleton pregnancy. The aim of this study was to assess whether vitamin D levels affect the outcomes of twin pregnancy and if targeted supplementation can improve perinatal outcomes. Methods: The serum vitamin D levels of 143 women with twin pregnancies were measured during their first trimester. Those with insufficient (10–30 ng/mL; IL group) or severely deficient (30 ng/mL, SL group) since the beginning of pregnancy. Results: Women in the IL and DL groups had a higher incidence of hypertensive disorders of pregnancy (HDP) compared to the SL group (24.8% and 27.8% vs. 12.5%, p = 0.045): OR = 1.58 for the IL group and 1.94 for the DL group compared to the SL group. In patients whose vitamin D levels were restored after supplementation, HDP incidence was lower than in patients who remained in the IL or DL groups (23.4% vs. 27.3%) but higher than those who were always in the SL group (12.5%). Conclusions: Insufficient or severely deficient levels of vitamin D in the first trimester are associated with an increased risk of HDP in twin pregnancy. The beneficial effect of targeted vitamin D supplementation in reducing HDP seems limited.

Listeriosis is a rare but severe foodborne disease caused by Listeria Monocytogenes (LM), a small facultative intracellular bacillus. When occurring in pregnant women, it can be vertically transmitted to the fetus and the newborn. Infected women usually display aspecific and mild symptoms, and rarely develop the severe forms of the disease (such as neurolisteriosis). On the contrary, fetal and neonatal listeriosis can lead to complications such as fetal loss, preterm birth, neonatal sepsis, and respiratory distress syndrome (RDS). Prompt diagnosis is one of the main challenges because of the aspecific presentation of the disease; therapy relies on antibiotics that reach high intracellular concentration and can penetrate and pass the placenta reaching the fetus. Herein we report an infrequent case of LM infection involving a woman with monochorionic diamniotic twin pregnancy, followed by a comprehensive review of the available literature on listeriosis in pregnancy.

Objectives: Twin pregnancy implies a higher risk of preterm birth and, consequently, higher neonatal morbidity and mortality. In singleton pregnancies, infections of the lower genital tract (LGTIs) and bacterial vaginosis are associated with preterm labor, and their early detection has been proven effective in reducing complications like the preterm premature rupture of membranes (pPROM) and preterm delivery. The same evidence, however, is lacking for twin pregnancies. This study aimed to evaluate whether the early identification and treatment of LGTIs or bacterial vaginosis in asymptomatic women with twin pregnancy could reduce the rate of miscarriages, pPROM, and preterm birth. Methods: This study performed a retrospective comparison of 285 women with a multiple pregnancy submitted for a cervico-vaginal swab only at 20–22 weeks (Single Test Group, STG), and 199 women who underwent the swab at 12–14 and again at 20–22 weeks (Double Test Group, DTG). All women included in the study had a twin pregnancy and were followed up at Sant’Anna Hospital, Turin (Italy), between September 2012 and February 2021. Results: In STG, 21.7% of patients had a positive swab; in DTG, 19.9% had an early positive swab that was immediately treated by targeted antibiotics; and 16.7% had a mid-pregnancy positive swab. The DTG showed a significantly lower incidence of pPROM in univariate analysis (14.4% vs. 23.1%, p = 0.021), which was confirmed by multivariate analysis (OR 0.55, CI 0.33–0.93, p = 0.025). Conclusions: Our study suggests that, in asymptomatic women with twin pregnancy, the early screening of LGTIs and bacterial vaginosis by a cervico-vaginal swab at 12–14 weeks of gestational age is effective in reducing the risk of pPROM.

Objectives: To describe the perinatal outcomes of a series of monochorionic diamniotic (MCDA) twin pregnancies complicated by selective fetal growth restriction (sFGR), classified according to the umbilical artery (UA) Doppler flow pattern of the smaller twin, and managed in a single centre over a 12-year period. Methods: Retrospective cohort study involving MCDA twin pregnancies followed up at the Twin Pregnancy Care Unit of Sant’Anna Hospital, Turin, Italy, between January 2010 and May 2023. We compared perinatal outcomes of MCDA pregnancies classified based on the UA Doppler flow pattern of the smaller twin. Results: The percentage of sFGR in our sample was 14.8%. A total of 103 MCDA pregnancies with sFGR were included. In 34.9% cases, the UA flow pattern changed throughout pregnancy. At last examination, 58.3% cases were classified as type I, 25.2% as type II and 16.5% as type III. The perinatal survival rate of both twins in type I and III was 100%, in type II 88.5%. Type II sFGR had the highest perinatal mortality rate (7.7%). Type III twins were more likely to have malformations compared to type II and type I; compared to type I sFGR babies, they were more likely to develop RDS and to be admitted to NICU, where the length of stay was longer. Conclusions: Although the UA flow pattern correlates with perinatal outcome, it can change throughout pregnancy. Type III sFGR may have lower risk of fetal demise than traditionally thought. The main challenge remains finding the optimal balance between adverse outcomes and premature birth.

Background: Dieulafoy’s disease is a rare vascular anomaly of the gastrointestinal tract and an uncommon cause of acute upper gastrointestinal bleeding. Its occurrence during pregnancy is exceptionally rare, and the available literature is limited to isolated case reports that almost invariably describe acute and overt hemorrhagic presentations. As a result, atypical or clinically silent forms of the disease during pregnancy remain poorly characterized. Objective: To report an atypical case of Dieulafoy’s disease during pregnancy, presenting exclusively with severe progressive anemia in the absence of gastrointestinal symptoms and to contextualize this observation through a focused narrative review of the literature. Methods: An illustrative clinical case is presented, followed by a narrative review of the available literature on Dieulafoy’s disease in pregnancy. Particular attention was given to pregnancy-related physiological and hormonal adaptations, diagnostic challenges, therapeutic strategies, and reported maternal–fetal outcomes. All published cases identified in the literature were reviewed and summarized. Results: In the general population, Dieulafoy’s disease typically presents with sudden and overt gastrointestinal bleeding and is most commonly localized in the proximal stomach. In pregnancy, reported cases are rare and have almost exclusively involved acute hemorrhage occurring in the second or third trimester, frequently requiring urgent endoscopic intervention. Mechanical endoscopic hemostasis represents the treatment of choice and is generally associated with favorable maternal and fetal outcomes. In contrast, the illustrative case described herein demonstrates a clinically silent presentation, characterized by severe and progressive anemia without hematemesis, melena, or hematochezia, resulting in delayed diagnosis until upper gastrointestinal endoscopy identified multiple actively bleeding gastric Dieulafoy’s lesions. Conclusions: Dieulafoy’s disease should be considered in the differential diagnosis of severe, unexplained, or transfusion-dependent anemia during pregnancy, even in the absence of overt gastrointestinal bleeding. Pregnancy-related physiological adaptations may mask classic symptoms and complicate timely diagnosis. When clinically indicated, upper gastrointestinal endoscopy is safe and effective during pregnancy and remains central to both diagnosis and management. Increased awareness of atypical presentations may facilitate earlier recognition and improve maternal and fetal outcomes.