Objective To evaluate the effects of operator experience on perinatal outcome in a single centre.Design Prospective consecutive cohort study.Setting Regional tertiary referral Fetal Medicine Centre in the UK.Population Pregnant women with monochorionic twin pregnancies complicated by severe twin-to-twin transfusion syndrome (TTTS) (at £26 completed weeks of gestatiuon) treated by fetoscopic laser coagulation (FLC) between October 2004 and November 2009.Methods Pregnancy characteristics and outcomes were collected. Logistic regression analysis was employed to determine the effect of a priori defined variables on outcome.Main outcome measure Perinatal survival (survival to 28 days or beyond) for one or more twins.Results There were 164 consecutive sets of monochorionic twins. The median gestational age (GA) at FLC was 20.4 weeks (interquartile range 18-22.1 weeks), the median interval from FLC to delivery was 88.5 days (interquartile range 53-101 days) and the median GA at delivery was 33.2 weeks (interquartile range 29.7-34.9 weeks). The overall survival was 62%; perinatal survival of one or more twins was 85%. These outcomes improved after about 61 procedures were performed, and after about 3.4 years of experience. Univariate logistic regression analysis indicated that Quintero stage-IV disease decreased (OR 0.26; 95% CI 0.10-0.69) and prolongation of GA at delivery increased the survival of the twins (OR 1.34; 95% CI 1.12-1.60) (P < 0.01). Increasing experience of the procedure by operator led to a significant increase in perinatal survival (P < 0.01; OR 4.59; 95% CI 1.84-11.44). Multivariate logistic regression analysis indicated that only GA at delivery increased survival overall (OR 1.34; 95% CI 1.12-1.60; P = 0.01).Conclusions These data indicate that both relatively large numbers treated and experience with FLC minimises any adverse outcome in monochorionic pregnancies with severe TTTS.Keywords Fetoscopic laser, perinatal outcome, Twin-to-twin transfusion syndrome.Please cite this paper as: Morris R, Selman T, Harbidge A, Martin W, Kilby M. Fetoscopic laser coagulation for severe twin-to-twin transfusion syndrome: factors influencing perinatal outcome, learning curve of the procedure and lessons for new centres.

Aim To evaluate the effects of Quintero stage at diagnosis on perinatal outcome in a single centre. Methods A cohort of consecutive monochorionic (MC) twin (MC) pregnancies complicated by severe TTTS (≤26 weeks) treated by fetoscopic laser ablation (FLA) (October 2004–June 2010). Results Of the 199 MC twins; 5% were Quintero stage II, 79% stage III & 16% stage IV. For the cohort overall the median gestational age (GA) at FLA was 20.1 weeks (IQR 18–22). The median interval from FLA to delivery was 87 days (IQR 54–101) & GA at delivery 33.7 weeks (IQR 30.3–34.9). There was no significant difference for the different stages of disease. Survival or one or more baby to 28 days was 92% for stage II disease, 88% for stage III and 69% for stage IV. The perinatal mortality for each of the groups was 38%, 36% and 53% respectively. Thus there was a decrease in survival and increase in perinatal mortality with advancing Quintero stage. This was not however, statistically significant. Univariate logistic regression analysis indicated that Quintero stage of disease had no effect on the survival of one or more babies to 28 days p=0.06 nor perinatal mortality p=0.47. Conclusion These data indicate that Quintero stage of disease and timing of fetoscopic laser ablation do not affect pregnancy outcome in severe TTTS. This is in concordance with data from studies from the USA but in disagreement with other European studies.

Aim To evaluate the effects of operator experience on perinatal outcome in a single centre. Methods A cohort of consecutive monochorionic twin (MC) pregnancies complicated by severe twin to twin transfusion syndrome (TTTS) (≤26 weeks) treated by fetoscopic laser ablation (FLA) (October 2004 to November 2009). Results Of the 164 MC twins; 5% were Quintero stage II, 79% stage III and 16% stage IV. The median gestational age (GA) at FLA was 20+2 weeks (95% CI 16 to 25+3). The median interval from FLA to delivery was 88.5 days (7 to 127) and GA of live born 33+5 weeks (28+2 to 36+1). Excluding pregnancy losses <24 weeks 100% of pregnancies had one live birth. In the first half (n=82) of the cohort, in 13% there were no survivors, in 55% both twins survived to birth, 43% both twins survived to 28 days postdelivery (at least one survivor in 76%). In the second half (n=82), corresponding values were 6%, 37%, 33% and 79%. Univariate logistic regression analysis indicated that lower Quintero stage (OR 3.84 (1.55 to 9.54)) and prolongation of GA increased survival of the twins (OR 0.75 (0.63 to 0.89), p<0.01). Increasing operator experience led to a significant reduction in perinatal death (OR 0.28 (0.1 to 0.74), p<0.01). GA at delivery (OR 0.93 (0.89 to 0.97), p≤0.01) was the only significant predictor of cerebral morbidity. Changes in use of trochar portals, selectivity of procedure and ablation at peripheral margins of the placenta will be described. Conclusion These data indicate that relatively large numbers treated and experience with FLA minimises adverse outcome in MC pregnancies with severe TTTS.

Aim To evaluate the effects of gestation (before or after 20 weeks (weeks)) at which fetoscopic laser ablation (FLA) is performed on outcome for severe TTTS. Methods A cohort of consecutive monochorionic twin (MC) pregnancies complicated by severe TTTS (≤26 wks) treated by FLA (October 2004–June 2010). Results Over the 6 year time period 199 sets of MC twins were managed with FLA; 93 cases were performed prior to 20 completed weeks gestation and 106 after 20 weeks. Prior to 20 weeks 2% were Quintero stage II disease, 79% stage III and 19% stage IV. For FLA after 20 weeks the distribution was 9%, 78% and 13% respectively. There was no significant difference in the stage distribution p=0.05. Survival of ≤1 baby to 28 days was 81% at <20 weeks and 89% at >20 weeks (p=0.65). There was no significant difference in outcomes between the two cohorts. However, the gestational age (GA) at delivery was later in the cohort where FLA was performed after 20 weeks. Multivariate logistic regression analysis revealed that GA at delivery was the only significant factor affecting survival ≤1 baby to 28 days in the group > 20 weeks (OR 1.25 95% CI 1.06 to 1.48 p=0.08). For perinatal mortality a later GA at delivery (OR 0.97 95% CI 0.95 to 0.99 p=0.008) and an experienced operator decreased perinatal mortality (OR 0.17 95% CI 0.04 to 0.83 p=0.03). Conclusion These data indicate that if FLA is performed <20 weeks then an experienced operator is required and that similar outcomes can be achieved.