Preterm delivery in triplet pregnancies.

Purpose: The purpose of this study is to assess the rate of spontaneous preterm birth (SPTB) versus indicated preterm birth (IPTB) in triplet pregnancies and determine factors associated with these outcomes.
Materials and Methods: This is a review of triplet pregnancies delivering at our institution from 2003 to 2015. Patients delivering prior to 24 weeks gestational age (GA) were excluded. SPTB included cases of preterm labor or preterm premature rupture of membranes <37 weeks. IPTB was defined as deliveries <37 weeks for maternal or fetal complications.
Results: Of 80 triplet pregnancies, 18 (22.5%) were not complicated by SPTB or IPTB and reached their scheduled delivery date. In the remaining 62 pregnancies, IPTB occurred in 31 patients and SPTB in 31 patients. Parity was the only significant factor associated with reaching a scheduled delivery, with 56.3% of parous women reaching a scheduled delivery versus 14.1% of nulliparous women (p = 0.001). There were no significant differences in maternal age, parity, chorionicity, or use of ART between the SPTB and ITPB groups.
Conclusions: While the majority of our triplet patients delivered preterm, IPTB occurred as frequently as SPTB in our population. Parous women were significantly less likely to experience SPTB or to require preterm delivery for maternal or fetal indications.