Relationship of Fetal Complications in Monochorionic Diamniotic Twin Pregnancy with Placental Site Cord Insertion: A Retrospective Analysis of 30 Months Data in a Referral Fetal Medicine Center
Authors: Suresh Indrani , Andrew Chitra , Seshadri Suresh 
Published: December 2016

ABSTRACT

Aims
Among the increasing twin gestations, monochorionic twins occur in about 12 to 15% of all twin gestations and the occurrence is about 1 in 20 in assistive reproductive technology pregnancies. Early detection of twin to twin transfusion syndrome (TTTS) or selective intrauterine growth restriction (sIUGR) aids the obstetrician in counseling and therapy as required.

Materials and methods
This is a retrospective cohort study of monochorionic diamniotic (MCDA) pregnancies referred from January 2011 to June 2013. Those cases that had crown rump length and nuchal translucency measurements done in the first trimester and then at least one subsequent scan at > 16 weeks, at the institution were chosen. The objective was to assess the utility of placental site of cord insertion in early second trimester scan to predict fetal outcome in monochorionic twin pregnancy.
The patient characteristics, placental cord insertion site, and neonatal outcomes were compared among TTTS, sIUGR, and normal groups.

Discussion
Of 89 MCDA pregnancies, only 60 had been referred for second trimester scan. Among these, in 48 (80%) of pregnancies, both babies were delivered and discharged alive and well. Cord insertions that were eccentric or central were classified as “type A”. Marginal and velamentous cord insertions were classified as “type B”. Pregnancies with both types A and B insertions were called “concordant cord insertions group” and the others were classified as “discordant cord insertions” group. The two groups were compared to look for the pregnancy complications — TTTS or sIUGR.

Results
The concordant cord insertions (n = 33) had 84.8% of pregnancies having a normal pregnancy and 12.1 and 3.1% developing sIUGR and TTTS respectively. The discordant cord insertion group (n = 27) had 59.2% with normal findings at the second scan and 14.8 and 26% developing sIUGR and TTTS respectively. The incidence of TTTS was 30% in twin pairs with discordant cord insertions and 3% in twin pairs with concordant cord insertions (p = 0.0158). Cord insertions did not influence the occurrence of sIUGR in our study. (p = 0.69). Significantly more pregnancies with concordant cord insertions had normal outcomes (p = 0.02).

Conclusion
Determination of placental site of cord insertion should be incorporated into protocols of twin pregnancy care. This is a window of opportunity to gain valuable information regarding the pregnancy. Further large studies incorporating fetal biometric and Doppler parameters could show the relative utility of each parameter in the detection of MCDA vascular complications. If the MCDA pregnancy can be classified as “low risk” then reassessment intervals can be extended. This would help to reduce patient stress and costs involved in repeated scans.

How to cite this article
Andrew C, Suresh I, Seshadri S. Relationship of Fetal Complications in Monochorionic Diamniotic Twin Pregnancy with Placental Site Cord Insertion: A Retrospective Analysis of 30 Months Data in a Referral Fetal Medicine Center. J South Asian Feder Obst Gynae 2016;8(4):304-308.