Results
After excluding monochorionic or dichorionic triplets, we identified 524 trichorionic triplet pregnancies which included 213 cases in expectant management (EM) group and 311 cases in embryo reduction (ER) group.
Table 1 shows the clinical characteristics of the study population. There were no differences in the mean maternal age and body mass index and the frequency of nulliparity and history of previous preterm birth between two groups. There were more cases becoming pregnant after in vitro fertilization (IVF) in the ER group than in the EM group.
Table 2 compares the obstetric outcomes between the two groups of cases. In the EM group, the risk of preterm delivery (<36, <34, <32, and <28 weeks) was higher compared to the ER group. However, in EM group, the risk of non-viable pregnancy loss was lower [2(0.9%) vs. 20(6.4%), p=0.008] that in ER group. Moreover, the rate of cases with at least one alive neonate were higher [208(97.7%) vs. 287(92.3%), p=0.013]. In terms of obstetric complications, the risk of preeclampsia was higher in EM group than in ER group [27 (12.8%) vs. 16 (5.5%), p<0.05], whereas the risk of gestational diabetes and postpartum hemorrhage was not different between the two groups. Even after adjustment for maternal age, BMI, and method of conception, the risk of non-viable fetal loss and the rate of no neonatal survivor were significantly lower in EM, whereas the risk of preterm delivery and preeclampsia was higher in EM than in ER group.
The study population included 1,261 fetuses: 639 in the EM group and 622 in the ER group (Table 3). The survival rate during 2 hours after birth [612(95.8%) vs. 552(88.7), p=0.001] and the survival rate until discharge of neonates were also significantly higher in the EM group than the ER group [607(95.0%) vs. 545(87.6), p=0.001]. The rate of neonates who admitted to NICU was higher in ER group [313(50.4%) vs. 201(36.3), p<0.001], but the risk of neonatal composite morbidity during hospitalization was not different between the two groups [113(19.1% vs. 105 (20.0%), p=NS). The risk of PDA and BPD was higher in EM group, but the risk of neonatal sepsis was lower in EM group [10(1.7%) vs. 27(5.1), p=0.017].
We evaluated the risk of developmental delay and cerebral palsy in 958 babies. The risk of developmental delay and cerebral were not significantly different between the two groups both in the univariable and multivariable analyses.