Evaluation of Trichorionic versus Dichorionic Triplet Gestations from 2005 to 2016 in a Large, Referral Maternity Center

Abstract

To evaluate trends in the proportions and outcomes of dichorionic-triamniotic (DT) compared with trichorionic-triamniotic (TT) triplet gestations. This is a retrospective cohort of all triplet gestations identified by first trimester ultrasound at an academic center between 2005 and 2016. Primary outcomes were the change in proportion of DT versus TT triplets over time and the number of fetuses at delivery. Secondary outcomes included differences in mode of conception and maternal/perinatal outcomes by chorionicity. Of 258 identified triplet pregnancies, 65.5% ( = 169) were TT. The proportion of DT versus TT triplets increased from 2005 to 2016 ( < 0.001). Women with DT triplets were more likely to deliver a singleton (41.4 vs. 11.2%, < 0.001). Mode of conception was known for 248 women, of whom 93.5% ( = 232) conceived through infertility treatment. Types of infertility treatment differed by chorionicity ( < 0.001), with DT triplets more likely to conceive through in vitro fertilization (88.3 vs. 60.7%). Women with DT delivered earlier than TT triplets (31.0 ± 5.0 vs. 33.1 ± 3.5 weeks; = 0.03). The proportion of DT triplet gestations increased significantly over time. Women with DT triplets delivered on average 2 weeks earlier than TT triplets. Women with DT triplets were more likely to reduce to a singleton gestation.

Maternal, Perinatal and Neonatal Outcomes of Triplet Pregnancies According to Chorionicity: Our 15-Year Experience in a Tertiary-Level Center

“…The main obstetric complication in this study, as well as in Revello’s study, was the threat of preterm labor (TPL), although in both cases, it was more than double the value reported in the meta-analysis (44% and 56% vs. 26.39%) [ 16 , 19 ], which included 25 studies [ 12 , 19 , 20 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. The precise causes underlying these findings remain unclear, although they could be explained by the variability of the diagnostic criteria in the cut-off points of sonographic cervical length, differences in access to a referral hospital and the bias corresponding to a high-risk population [ 19 ].…”

“…The prevalence of hypertensive states of pregnancy in our study was similar to that of Revello and that of our meta-analysis (16.3% vs. 20.4% vs. 14.18%) [ 16 , 19 ]. Nevertheless, as emphasized in the meta-analysis, there is a notable variability (ranging between 3 and 59%) among the 34 included studies, which could potentially be attributed to variations in the definitions used for diagnosis [ 12 , 14 , 19 , 20 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 33 , 34 , 35 , 36 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]. Preeclampsia occurs in 20–45% of women with multiple pregnancies and 5% of women with singleton pregnancies [ 55 , 56 , 57 , 58 ], and there is an established correlation between its severity and the degree of multiple pregnancies [ 59 ].…”

“…Geipel found that in monochorionic and dichorionic triplets compared to trichorionic triplets, there was a higher rate of intrauterine fetal death (8.8% vs. 1.5%) and of delivery at <32 weeks of gestation (47.4% vs. 32.2%) [ 39 ]. Indeed, Peress described that dichorionic triplets delivered on average two weeks earlier than trichorionic triplets [ 40 ]. In another study, Lopes Perdigao described that dichorionic triplet pregnancies were more likely to deliver before 30 weeks (25.5% vs. 8.3%) and to have very low birthweight neonates (41.8% vs. 22.2%) [ 22 ].…”

Perinatal outcome and long‐term hospitalization of triplets according to birth order

“…The average gestational age at delivery for triplet pregnancies has not changed significantly over the last 30 years and is 32-33 weeks. 21,22 The risk of preterm delivery before 34 weeks is 50%, while approximately 8%-17% of triplets are delivered extremely prematurely, between 24 and 28 weeks. 17,19 Preterm delivery is driven by both spontaneous preterm labor and indicated preterm birth due to maternal complications.…”

“…Rates of preterm delivery approach 100% in triplet pregnancies and perinatal outcomes are closely related to the gestational age at delivery. The average gestational age at delivery for triplet pregnancies has not changed significantly over the last 30 years and is 32–33 weeks 21,22 . The risk of preterm delivery before 34 weeks is 50%, while approximately 8%–17% of triplets are delivered extremely prematurely, between 24 and 28 weeks 17,19 .…”