Objective: To study the influence of the mode of delivery in uncomplicated monochorionic diamniotic (MCDA) twins ≥ 32 weeks of gestation. Design: Single-center retrospective cohort study. Setting: Department of Materno Fetal Medicine. Virgen del Rocío University Hospital. Population or sample: A total of 72 MCDA twins between 2012 and 2018. Methods: Outcomes were compared between women who underwent a trial of labor (TOL) (induced or spontaneous onset of labor) and those who underwent a planned cesarean section (PCS). Main outcome measures: (1) A composite of any of the following: neonatal death, 5-minute Apgar score <4, respiratory distress syndrome, bronchopulmonary dysplasia, sepsis, periventricular leukomalacia, intraventricular hemorrhage, and necrotizing enterocolitis. (2) Neurodevelopmental impairment (NDI) at 2 years of corrected age. Results: In this period, 42 women (58.3%) had a TOL and 30 women (41.7%) had a PCS. In the TOL group, 64.3% achieved vaginal delivery. The rate of successful vaginal delivery was similar regardless of whether the onset of labor was spontaneous or induced. Composite perinatal morbidity was higher in the PCS group (aOR 1.36, 95% CI 0.24-7.81) and, considering the onset of labor, it was more frequent in the spontaneous subgroup (8.3% vs. 0%). The rate of NDI was higher in the PCS group [10.2% vs. 4.9%, aOR 1.53 (95% CI 0.37-6.29)]. Conclusions: In uncomplicated MCDA twins at ≥ 32 weeks of gestation, when the first twin is in vertex presentation, trial of labor is a safe approach with a successful outcome and high vaginal delivery rate.

Ductus arteriosus aneurysm (DAA) is characterized by a saccular or fusiform dilatation of the ductus arteriosus. The formation of a thrombus at that level is infrequent and potentially lethal. We present a case of a fetus with a DAA diagnosed during fetal life by 2-D, 3-D, and 4-D STIC echocardiography. Although a thrombus in the ductus and hypertrophy of the right ventricle was identified in postnatal echocardiography, a conservative approach was adopted with good outcome. The features of our case highlight the importance of serial ultrasound in the fetal and neonatal period to assess fetal aneurysm growth as well as to notice any modification of the flow within.