Introduction: Selective intrauterine growth restriction (sIUGR) is a complication observed in about 10-15% of all monochorionic (MC) pregnancies, causing a significant increase in perinatal mortality and morbidity.Objective: To evaluate clinical management options and perinatal outcomes of sIUGR in MC pregnancies monitored in a single tertiary center.Methods: A retrospective study was performed on 55-MC pregnancies with sIUGR between January 2012 and May 2018 at the Fetal Medicine Unit of La Paz Hospital. Cases were classified according to the umbilical artery (UA) Doppler pattern as type I (positive end-diastolic flow; n = 25), type II [persistently absent or reversed end-diastolic flow (AREDF); n = 5] and type III [intermittently absent or reversed end-diastolic flow (iAREDF); n = 25]. Types II and III were then merged together as severe sIUGR cases. Subsequently, two possible approaches were considered: expectant management (EM) with elective preterm delivery in case of fetal deterioration, or in-utero therapy via fetoscopic laser photocoagulation (FLP) of intertwin anastomosis or selective umbilical cord occlusion (CO) of the growth-restricted fetus.Results: Gestational age (GA) at diagnosis was progressively lower with each type. Severe sIUGR cases delivered significantly earlier than type I, showing lower birth weights and higher intertwin biometric discordance. Unintended fetal demise occurred in 14% (6/25) of severe sIUGR pregnancies as opposed to 0% (0/19) in type I, p = .028. A significantly higher proportion of twins was admitted in NICU in severe cases when compared to type I [87% (33/38) versus 47% (18/38), p < .001]. In addition, brain damage at birth was also found to be more prevalent in this group [21% (8/38) versus 11% (4/38), p = .346], especially in the larger twin, when comparing any short-term neurological sequel [30% (7/23) versus 0% (0/19), p = .011] or specifically periventricular leukomalacia [PVL; 22% (5/23) versus 0% (0/19), p = .053]. Although the overall mortality rate was significantly higher in severe sIUGR that underwent CO instead of EM [58% (7/12) versus 11% (4/36), p = .002], NICU admissions were higher in the latter [94% (17/18) versus 40% (2/5), p = .021]. Neurological sequels at birth were similar in both groups [39% (7/18) versus 40% (2/5), p = 1.000], similarly when considering only the larger twin for any brain lesion [28% (5/18) versus 40% (2/5), p = .621] or just PVL [22% (4/18) versus 20% (1/5), p = 1.000].Conclusion: Given the good prognosis of type I sIUGR, expectant management is the first approach to consider. However, due to the poorer clinical evolution of types II and III sIUGR, the decision-making is challenging and needs to be individualized depending on the UA Doppler pattern, GA at diagnosis, severity of growth restriction and biometric discordance, technical issues and parents' preferences.
Keywords: Fetoscopic laser photocoagulation; in-utero therapy; monochorionic pregnancies; selective intrauterine growth restriction; umbilical cord occlusion.