A total of 23 monochorionic diamniotic pregnancies met the initial inclusion criteria. However, three patients were excluded because preterm labor occurred before the laser procedure could be performed. One additional patient was excluded because she was bearing triplets. For the 19 pregnancies that were included in the present study, severe TTTS (stages III and IV) was confirmed using ultrasound examination. The mean gestational age at diagnosis was 20 (range: 17–25) weeks. Nine pregnancies were classified as stage III, and ten as stage IV.
The mean gestational age at fetoscopic laser ablation was 22.0 (range: 19.0–26.0) weeks. There was no statistical difference in gestational age at the time of the procedure between patients with TTTS stage III (mean: 21.0; range: 20.0–25.0) and those with stage IV (mean: 22.0; range: 19.0-26.0; p=0.38). The number of anastomoses coagulated per procedure varied from 7 to 13 and was similar in both groups (p=0.42). The placenta was posterior in 10/19 (52.6%) pregnancies and anterior in 9/19 (47.4%). In the present study, a second fetoscopic laser coagulation was not required for any of the cases. There were no serious maternal complications during or after fetoscopy. There was no need for blood transfusion, laparotomy or admission to an intensive care unit.
Preterm premature rupture of the membranes (PPROM) occurred in 2/19 (10.5%) pregnancies (one was a TTTS stage III patient and the other was stage IV). In the first case, PPROM occurred two weeks after the procedure, which was performed at 24 weeks of gestation. At 26 weeks, the patient delivered vaginally and both twins died on the second day of life. A second patient with stage III TTTS underwent fetoscopic laser therapy at 25 weeks. PPROM occurred seven weeks after fetoscopic laser therapy. The patient delivered one baby who is currently healthy (the donor twin died two days after laser therapy).
Recurrence of polyhydramnios in the recipient’s amniotic sac occurred in 3/19 (15.8%) pregnancies in which both twins survived after fetoscopic laser photocoagulation. In one patient, polyhydramnios recurred eight weeks after the procedure, and two amnioreductions were performed. The donor, who had already exhibited ventriculomegaly before the laser procedure, died in utero at 30 weeks of gestation. A Caesarean section was performed at 32 weeks; the recipient is currently healthy. In another patient, recurrence of polyhydramnios was observed four weeks after fetoscopic laser coagulation, and three amnioreductions were performed; the donor died in utero at 29 weeks. A Caesarean section was performed because of fetal distress and meconium at 31 weeks. The recipient died two days after birth. In a third patient, recurrent polyhydramnios was diagnosed three weeks after the procedure and three amnioreductions were performed. In this patient, tocolytic medication (beta-agonist) was used continuously from 22 to 26 weeks, and a Caesarean section was performed at 26 weeks of gestation. However, the recipient died one day after birth and the donor one week later.
Spontaneous preterm labor occurred in 8/19 (42.1%) pregnancies. In a further 5/19 (26.3%) pregnancies, patients were delivered prematurely before 32 weeks because of fetal distress. The overall mean gestational age at delivery was 32.1 (range: 26.0–38.0) weeks of gestation. Prematurity was more severe among pregnancies with stage IV disease (mean: 31.3 weeks; range: 26.0 – 36.0) than among those classified as stage III (mean: 33.8 weeks; range: 30.0 – 38.0; p<0.01).
Perinatal results are shown in . The overall survival rate was 52.6% (20/38). The percentage of pregnancies in which both twins survived was 26.3% (5/19). Survival of only one twin occurred in 52.6% of cases (10/19), thus resulting in a survival rate for at least one baby of 78.9% (15/19). The survival rates for recipient and donor twins were similar at 52.6% (10/19). Recipient fetal mortality occurred in 31.6% (6/19) of cases while mortality of the donor fetus occurred in 36.8% (7/19). Neonatal deaths occurred in 3/19 (15.8%) of recipient babies and in 2/19 (10.5%) of donor babies. Among all survivors (n=20), there was no intraventricular hemorrhage, periventricular leukomalacia, ventriculomegaly or cerebral palsy detected at up to 30 days of life. In one case, a disproportionally smaller right leg of the recipient twin was noted at birth after 29 weeks of gestation (the donor died one day after fetoscopic laser therapy at 26 weeks).
Table 1 -
Perinatal results of 19 pregnancies with TTTS stages III and IV treated with fetoscopic laser photocoagulation
According to the Quintero stages, there was a tendency for increased perinatal survival for stage III TTTS as compared to stage IV cases; however this difference did not reach statistical significance (). There was no cerebral morbidity among the 17 babies that survived.