A Retrospective Analysis of Placentas From Twin Pregnancies Derived From Assisted Reproductive Technology

Abstract

There are conflicting studies associating twin pregnancies derived from assisted reproductive technology (ART) with preterm birth, low birthweight, and other negative outcomes. This work investigates whether ART is linked with any placental pathology, given that placentation significantly influences fetal development. A 5-year, retrospective cohort study was conducted on placentas from twin pregnancies. The placental information from 417 patients was divided into two groups: placentas derived from ART and placentas derived from spontaneous pregnancies (non-ART). Available clinical information and pathologic findings from both groups then were compared. There was no statistical difference in the prevalence of placental pathology between the non-ART and ART cohorts (i.e., cord insertion, single umbilical artery, cord knot, retroplacental hemorrhage, infarction, vasculopathy, vascular anastomoses, chorangiosis, villitis, deciduitis, chorioamnionitis, meconium staining). However, 8% of ART multiple pregnancies were monochorionic. While monochorionicity is a known risk factor for adverse obstetric and neonatal outcomes, the rate of monochorionic placentation did not increase as a result of ART. Nevertheless, it is interesting to note that this small percentage of monochorionic placentation occurred in the ART cohort despite the implantation of individual embryos. Overall, the data suggests that ART does not have a role in the pathologic placentation of twin pregnancies.

Adverse pregnancy, birth, and infant outcomes in twins: effects of maternal fertility status and infant gender combinations; the Massachusetts Outcomes Study of Assisted Reproductive Technology

“…In spontaneously-conceived twin pregnancies, the prevalence of dizygotic twinning varies with race and ethnicity, from a low of 1.3/1,000 live births in Asia to 50/1,000 live births in Africa, as well as increasing with the maternal factors of older age, taller height, higher parity, and family history of twinning (58, 59). Prior to the advent of assisted reproductive technologies, the rate of monozygotic twinning was relatively constant worldwide at about 4/1,000 live births, regardless of maternal or familial factors (60); it has been estimated that the incidence has more than doubled with assisted conception (8–9/1,000 live births) (61, 62). In ART treatment, the main risk factor for dizygotic twins and higher-order multiple pregnancies is the transfer of more than one embryo (63, 64), as well as taller maternal stature (>68 inches) and higher number of oocytes retrieved (>8) (65).…”

Obstetric and Perinatal Outcomes of Dichorionic Twin Pregnancies According to Methods of Conception: Spontaneous Versus In-Vitro Fertilization

“…Although the results showed that twins with dizygosity by restriction to 'unlike sex' had beneficial outcomes among the ART group, the authors indicated that it was doubtful to generalize this subset of dizygotic twins to all dizygotic twin deliveries. Most studies regarding chorionicity analyzed gender difference to define dizygosity because it was largely contributed to the dichorionic placentation, however, a possible explanation about dizygous monochorionic twinning has been propounded by several reports and dizygosity could not be determined by gender (Chan et al, 2007;Souter et al, 2003). In investigation to evaluate the gender mix of twin pregnancies, moreover, the gender combination might influence the length of gestation and birthweight independent of chorionicity (James, 2002;Luke et al, 2005).…”

Perfil clínico-epidemiológico das gestações gemelares com parto no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo no período de 2003 a 2006

“…A incidência da gestação monozigótica é de aproximadamente 1 em 250 gestações e relativamente constante em todas as populações, independente da raça, idade ou paridade materna [34,54] . No entanto, estudos têm demonstrado aumento das gestações monozigóticas relacionado com as técnicas de reprodução assistida, principalmente devido à duração do intervalo entre a formação do zigoto e a implantação dele na cavidade uterina [55,56] .…”