Vadlamudi G, Goyert G, and Shaman M. Growth outcomes of marginal cord insertion stratified by distance from placental margin. Am J Obstet Gynecol 2022; 226(1):S245.
Am J Obstet Gynecol
Objective: To compare the rates of fetal growth restriction (FGR) and small for gestational age (SGA) birthweight for patients with the sonographic diagnosis of marginal cord insertion at 1.0 cm or less, versus 1.01 to 2.0 cm, between the placental margin and cord insertion.
Study Design: Patients sonographically diagnosed with marginal placental cord insertion (cord insertion 2.0 cm or less from the placental margin) were identified. The distance was further classified as ≤1.0 cm or 1.01 to 2.0 cm. The presence of absence of FGR (estimated fetal weight less than 10%ile) and the presence or absence of SGA (birth weight less than 10%ile) were recorded.
Results: Marginal cord insertion was diagnosed in 163 cases; 70 cases had a placental cord insertion distance of ≤1.0 cm, and 93 cases had a distance of 1.01 to 2.0 cm. All cases of marginal cord insertion had significantly higher rates of FGR (16.0%) and SGA (15.8%) than the baseline population. In the group with a placental cord insertion distance of 1.0 cm or less, the rates of FGR (18.6%) and SGA (30.0%) were also higher than the general population. In cases with a distance between 1.0 and 2.0 cm, the rate of FGR (14.0%) was not significantly different than the general population; however, there was a higher rate of SGA (22.6%).
Conclusion: Marginal cord insertion of ≤1.0 cm is a significant risk factor for FGR and SGA; when 1.01 to 2 cm, marginal cord insertion remains a significant risk factor for SGA. This calls for continued antenatal surveillance with serial growth assessments for patients with marginal cord insertion defined as placental cord insertion 2.0 cm or less from the placental margin.