Placental location site and adverse antepartum pregnancy complications: a meta-analysis and review of the literature.

PURPOSE: The purpose to the study was to determine the relationship, if any, between the placental location site and antepartum complications of pregnancy. METHODS: A University research librarian conducted a comprehensive literature search using the search engines PubMed and Web of Science. The search terms were "placental location" AND "pregnancy complications" OR "perinatal complications. There were no limits put on the years of the search. RESULTS: The search identified 110 articles. After reviewing all the abstracts, relevant full articles, and references of full articles, there were 22 articles identified specific to antepartum complications. Central + fundal locations compared to all lateral were associated with a lower risk of hypertension during pregnancy RR = 0.47, 95% CI: 0.31-0.71]. Central location compared to all lateral was also associated with lower risk of hypertension during pregnancy [RR = 0.39, 95% CI: 0.26-0.59]. Placenta locations in the lower uterine segment were associated with greater risk of antepartum hemorrhage (APH) [RR = 2.99, 95% CI: 1.16-7.75] compared to above the lower uterine segment. No differences were observed in placental locations and gestational diabetes (GDM), preterm prelabor rupture of membranes (PPROM), preterm delivery (PTD) or on a placental abruption. CONCLUSION: Central and fundal location sites and central location alone decreased the risk of hypertension during pregnancy. Low uterine segment location sites increased the risk for APH. There were no effects of placenta location sites on the development of GDM, PPROM, PTD or abruption.