Morphological anomalies in the placentae of IVF pregnancies: preliminary report of a multicentric study

Abstract

Macroscopic characteristics of 100 fetal adnexae from pregnancies obtained by in-vitro fertilization and embryo transfer (IVF-ET) were compared with data for normal pregnancies taken from the literature. Material was obtained from 63 singleton, 15 twin, one triplet and one quadruplet pregnancies. The fetal and placental weights as well as the fetal:placental weight ratio were within the normal range for gestational age. Whilst placental morphology was normal, the insertion of the umbilical cord was frequently abnormal. Marginal (15%) and velamentous (14%) insertions of the umbilical cord were found more frequently than in a general obstetrical population (6% and 1% respectively). Excluding placentae from multiple pregnancies (which are known to have a higher incidence of abnormal cord insertion) the frequency did not decrease and remained significantly higher than in a normal population (P less than 0.01 and P less than 0.001, for marginal and velamentous insertion respectively). Abnormal insertion of the cord is of major clinical importance because of its association with vasa praevia and fetal haemorrhage (Benkiser Syndrome). Since this condition is thought to be caused by disturbed orientation of the blastocyst at implantation it is probably related to the IVF-ET procedure.

Umbilical cord anomalies are more frequent in twins after assisted reproduction

“…The higher incidence of abnormal cord insertion in ARTpopulations has been previously observed in smaller sample sizes (Englert et al, 1987;Jauniaux et al, 1990). We compared cord anomalies according to different types of artificial techniques in the same fashion as Daniel et al (2001).…”

“…The relationship between mode of conception (spontaneous conception versus conception after IVF) and abnormal cord insertion in both singletons and twins has been investigated only in small populations (n , 100; Englert et al, 1987;Jauniaux et al, 1990;Gavriil et al, 1993;Daniel et al, 2001;Narine et al, 2003), whereas the association between assisted reproductive technologies (ART) and SUA has so far escaped research. The availability of the population-based East Flanders Prospective Twin Survey (EFPTS) with data on .6000 twin pairs encouraged us to analyse cord insertion differences between naturally conceived twins and twins born after assisted reproduction.…”

Various Doppler sonographic appearances and challenges in prenatal diagnosis of vasa praevia

“…The rates of velamentous and marginal cord insertions are 14% and 15%, respectively, in the overall population but may be higher among single-fetus pregnancies achieved by IVF, 10,11 as in our second case. These insertion anomalies were traditionally thought to be due to poor ori- entation of the blastocyst at the time of implantation.…”

“…Others have hypothesized that in cases of IVF, placement of the blastocyst directly in the endometrium at the time of transfer makes normal orientation of the embryo impossible. 10 However, a prospective study is needed to test these hypotheses, none of which appears plausible. It seems prudent to recommend systematic sonographic screening for cord insertion in pregnancies achieved with medical assistance, particularly in cases of IVF and intracytoplasmic sperm injection.…”

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

“…Interestingly, dissimilar results were not only observed in twin studies. For singleton pregnancies, analyses comparing ART and non-ART-derived placentas also show some variability in results (Daniel et al, 1999;Englert et al, 1987;Gavriil et al, 1993;Lalosevic et al, 2003). The reasons for the differences between these individual studies are not clear; however, it was our hope to add our institutional experience, sample size, and comprehensive placental examination to the literature for others to analyze.…”