Marginal Sinus and Bleeding in Women with a Low-Positioned Placenta: A Narrative Synthesis Systematic Review

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Reproductive Health

Background:

• Low-positioned placenta is associated with increased risk of hemorrhage.
• Marginal sinus, a vascular structure at the placental edge, may influence bleeding risk.

Purpose of the Study:

• To evaluate the impact of marginal sinus on antepartum, intrapartum, and postpartum hemorrhage in women with low-positioned placenta.
• To synthesize current evidence on the association between marginal sinus and bleeding complications in low-positioned placenta.

Main Methods:

• Systematic review of cohort studies.
• Searched PubMed, Scopus, EMBASE, and Cochrane Library (1980-2024).
• Included 6 cohort studies (2 prospective, 4 retrospective) with 621 women.

Main Results:

• Four of five studies found a significant association between marginal sinus and antepartum hemorrhage.
• No association was reported between marginal sinus and intrapartum hemorrhage in two studies.
• One study indicated lower postpartum bleeding rates with normally located placenta and marginal sinus compared to low-positioned placenta.

Conclusions:

• The association between marginal sinus and bleeding risk in low-positioned placenta remains poorly evaluated.
• Evidence is inconsistent, necessitating further research for definitive conclusions and clinical guidance.
• Current studies did not adequately address the role of marginal sinus in diagnosing and managing low-positioned placenta.