OP17.08: Cervical length and cervical infection as predictors of success of laser therapy in twin‐to‐twin transfusion syndrome (TTTS)

Abstract

Objectives: A short cervix in a pregnancy complicated by TTTS and LASER treatment has been shown to be an independent risk factor for preterm birth (PTB) putting survival at risk. We aimed for identification of patients whose risk for spontaneous abortion or extremely PTB is increased so the effort of LASER therapy must be considered inappropriate. Methods: 196 patients who underwent LASER therapy for TTTS in 2004-2007 were included. All women's cervical lengths (CL) on transvaginal ultrasound (TVS) and cervical colonization patterns were analyzed 24h before LASER. All received a single dose of 1g Cefazolin i.v. during the procedure. We investigated the association between an abnormal smear and prematurely losing the pregnancy. Results: 16 women (RR=8.2%) lost both fetuses by miscarriage or extremely PTD leading to immediate neonatal death. CL (total n=182) were significantly shorter in those who aborted. However, there were outliers, i.e. 7 women with a CL of <20 mm, who later gave birth to at least one survivor. Smear results were attributed to 3 groups: local standard flora (1), bacterial vaginosis or other (2) and (3) presence of fetopathic microorganisms. Of 190 smears, 79 were classified as normal (1), 111 as abnormal (63x group 2, 48x (3)). There was no association between an abnormal smear (group 2+3) before LASER and pregnancy loss (OR 0,8; p=0.53): a questionable association between being GBS+ at baseline (n=16) and later loss (OR 1,77; p=0.48) will undergo further investigation. Conclusion: TVS can identify patients at risk for pregnancy loss better than cervical smears. There is no reason to deny LASER treatment to any woman with TTTS not in labor on the basis of an abnormal smear or a short cervix.