Risk factors associated with preterm delivery after fetoscopic laser ablation for twin-twin transfusion syndrome

Abstract

OBJECTIVE Despite improved perinatal survival following fetoscopic laser surgery (FLS) for twin twin transfusion syndrome (TTTS), prematurity remains an important contributor to perinatal mortality and morbidity. The objective of the study was to identify risk factors for complicated preterm delivery after FLS. STUDY DESIGN Retrospective cohort study of prospectively collected data on maternal/fetal demographics and pre-operative, operative and post-operative variables of 459 patients treated in 3 U.S. fetal centers. Multivariate linear regression was performed to identify significant risk factors associated with preterm delivery, which was cross-validated using K-fold method. Multivariate logistic regression was performed to identify risk factors for early vs. late preterm delivery based on median gestational age at delivery of 32 weeks. RESULTS There were significant differences in case selection and outcomes between the centers. After controlling for the center of surgery, a multivariate analysis indicated a lower maternal age at procedure, history of previous prematurity, shortened cervical length, use of amnioinfusion, 12 Fr cannula diameter, lack of a collagen plug placement and iatrogenic preterm premature rupture of membranes (iPPROM) were significantly associated with a lower gestational age at delivery. CONCLUSION Specific fetal/maternal and operative variables are associated with preterm delivery after FLS for the treatment of TTTS. Further studies to modify some of these variables may decrease the perinatal morbidity after laser therapy.

Iatrogenic Preterm Premature Rupture of Membranes after Fetoscopic Laser Ablative Surgery

“…In TTTS, iPPROM rates up to 50% have been reported, although the exact incidence of surgery-related rupture versus the increased baseline risk of PPROM in monochorionic twins is difficult to determine. Several recent series from large fetal centers have reported a 28-42% incidence of iPPROM before 32 weeks of gestation of [6,12]. Notably, the risk of rupture of membranes is twice as high in twin gestations as in singleton gestations [13].…”

“…Because of this, reported rates of iPPROM range from 2 to 50% [5], with a recent systematic review reporting an average rate of 27% [4]. Most recently, a multicenter retrospective study examining the risk factors associated with preterm delivery after fetoscopic laser ablation reported an overall iPPROM rate prior to 32 weeks of gestation of 28% [6], while the multicenter prospective randomized control study on the Solomon technique reported iPPROM rates before 32 weeks of 34-42% [7]. Several risk factors for iPPROM have been identified, including the size and number of ports used, duration of the procedure, type of anesthesia, gestational age (GA) at intervention, placental location, and operator experience [4,6].…”

“…Most recently, a multicenter retrospective study examining the risk factors associated with preterm delivery after fetoscopic laser ablation reported an overall iPPROM rate prior to 32 weeks of gestation of 28% [6], while the multicenter prospective randomized control study on the Solomon technique reported iPPROM rates before 32 weeks of 34-42% [7]. Several risk factors for iPPROM have been identified, including the size and number of ports used, duration of the procedure, type of anesthesia, gestational age (GA) at intervention, placental location, and operator experience [4,6]. The objective of our study is to define the rate of iPPROM in cases of laser surgery for TTTS at our institutions and to determine potential contributable risk factors.…”

Histologic changes of the fetal membranes after fetoscopic laser surgery for twin-twin transfusion syndrome

“…One possibility is that mechanical injury to the fetal membranes triggers a cascade of events yet to be determined that ultimately induces generalized cell death of the recipient's amniochorion; Alternatively or concurrent changes in the AF milieu due to the pathophysiology of the TTTS or related to amnioinfusion of LR solution during surgery may affect the concentration of essential nutrients required to sustain viability of the fetal membranes and in particular amnion (10,21). The latter possibility is supported by our observation that the recipient's AF had significantly lower levels of glucose, proteins, and LDH levels, suggestive of polyhydramnios-induced dilution.…”

“…Aside from the cost of caring for the premature infants, preterm delivery is directly associated with long-term neurological deficits in TTTS (4,6), undermining the complete benefits of such intervention. PPROM which affects 20-32% of cases is the most important risk factor leading to preterm delivery (2,(7)(8)(9)(10).…”