Maternal complications in molecularly confirmed diandric and digynic triploid pregnancies: single institution experience and literature review

Abstract

Objectives Assessment of the maternal complications in molecularly confirmed diandric and digynic triploid pregnancies. Methods Sonographic features, biochemical results, and clinical presentation were analyzed. Beta-hCG level was controlled after diandric triploidy. Results The study included nine diandric and twelve digynic triploid pregnancies at the mean gestational age at diagnosis of 14.9 and 18.0 weeks, respectively (p = 0.0391). Mean value of total-hCG was 979 703.6 U/ml in diandric cases and 5 455.4 U/ml in digynic ones (p < 0.000). Maternal complications occurred in 88.9% of diandric triploid pregnancies, including: thecalutein cysts (44.4%), hyperemesis gravidarum (44.4%), symptomatic hyperthyreosis (33.3%), early onset gestational hypertension (22.2%) and vaginal bleeding (11.1%). No case of proteinuria, preeclampsia or HELLP syndrome was observed. Only maternal complication observed in digynic triploidy was vaginal bleeding (50.0%). The mean time of beta-hCG normalization after diandric triploid pregnancies was 84 days (range 11–142 days). No case of gestational trophoblastic neoplasia (GTN) was observed. Conclusions Maternal complications (except for vaginal bleeding) are associated with diandric triploidy. The relatively low incidence of hypertensive maternal complications and their less severe course in our cohort may be attributed to the earlier prenatal diagnosis. The frequency of GTN after diandric triploidy may be lower than previously reported.

Genome‐wide abnormalities in embryos: Origins and clinical consequences

“…[41][42][43][44] Digynic pregnancies are associated with severe asymmetrical fetal growth restrictions (FGRs) and a small placenta, while diandric triploidy shows relatively well-grown fetus or symmetrical FGR and large cystic placenta. [45][46][47] In addition, diandric triploidy underlies both complete hydatidiform moles (CHMs) and partial hydatidiform moles (PHMs), although CHM is more evident in pure androgenesis in the absence of the maternal genome. 48 -557 F I G U R E 2 Visualization of the concept of heterogoneic division leading to genome-wide aberrations in case of a normal fertilization.…”

“…As reviewed, 49 there also seems to be a variable ratio of digynic:diandric triploidy at different gestational age, with more digynic triploids surviving into the third trimester. This is likely due to the negative pronounced effect of diandry on placenta development and function, which might also potentially explain why diandric triploidy is associated with higher risk of maternal pregnancy complications 46 . Hence, timely identification of fetal triploidy, including the origin of extra parental chromosomes, can have clinical implications for genetic counseling and pregnancy management.…”

Distribution of diandric and digynic triploidy depending on gestational age

“…Therefore, weekly monitoring of hCG should be implemented after all diandric triploid pregnancies in order to timely diagnose and treat potential neoplasia [22]. Moreover, diandric cases are associated with an increased risk of other maternal complications such as hypertension or hyperthyreosis [23].…”

Triploid pregnancy–Clinical implications

“…Some imprinted genes are methylated in oocytes and unmethylated in spermatozoa, while other imprinted genes are methylated in paternal germ cells and unmethylated in the maternal ones 29 . The imprinted gene expression is maintained in the placental tissue as well as in the amniotic cells, even in cases with placental pathology 11,29,30 …”

“…Neither non‐invasive prenatal screening (such as combined first trimester screening or cell free DNA testing) nor standard array comparative genomic hybridization (aCGH), detect triploidy, thus early sonographic diagnosis is essential in order to indicate proper molecular testing. Furthermore, diandric triploidy is associated with an increased risk of maternal complications such as preeclampsia, hyperthyreosis or gestational trophoblastic neoplasia (GTN) and post‐gestational surveillance is recommended 10–12 …”