How Have the Baseline Characteristics and Outcomes of Triplet Pregnancies Changed over the Last Two Decades?

Objectives: Triplet pregnancies are high-risk pregnancies, and its baseline characteristics and gestational care protocols have changed over the years. The objective of this study is to compare the baseline characteristics and the prevalence of maternal, fetal, obstetric, and perinatal outcomes between triplet pregnancies conceived between 2013 and 2024 (period II [PII]) and those conceived between 2000 and 2012 (period I [PI]).

Methods: This was a single-centre, observational retrospective case-control study that included all triplet pregnancies followed up at the La Paz University Hospital between 2000 and 2024. Univariate and multivariate statistical studies were performed.

Results: A total of 234 triplet pregnancies were analyzed, with 140 in the PI group and 94 in the PII group. Maternal age (P = 0.04) and nulliparity rate (P < 0.01) were higher in the PII group, although pregnancies conceived through assisted reproductive techniques were more frequent in the PI group (P = 0.04). The percentage of dichorionic triamniotic pregnancies was significantly higher in the PII group (P < 0.01), and the percentage of trichorionic triamniotic pregnancies was significantly higher in the PI group (P < 0.01). Preeclampsia (P < 0.01), intrauterine growth restriction (P < 0.01), fetal death (P < 0.01), neonatal death (P = 0.04), and small for gestational age (P < 0.01) were significantly more frequent in the PII group. Threatened preterm labour (P < 0.01) and extremely premature births (P < 0.01) were significantly more frequent in the PI group. After adjusting for confounders, premature birth was the only outcome that remained significant (adjusted P = 0.01).

Conclusions: The baseline characteristics of the PII group (higher maternal age and higher rates of nulliparity and dichorionic triamniotic pregnancy) might be associated with a higher rate of obstetric and fetal complications during this period. Rates of premature birth and threatened preterm labour have decreased over the years, which is probably related to advances in gestational care.