Effect of a low‐lying placenta on delivery outcome

Abstract

Objectives

Maternal and perinatal outcome in placenta previa - one year study in tertiary care center in Tamil Nadu, India

“…Vergani and colleagues reported that more than two thirds of women with placental edge and os distance >1 cm and 1-2 cm within 4 weeks of delivery according to Bronsteen had successful vaginal delivery. 19,20 In our case, only one had normal successful vaginal delivery.…”

Abnormal Placentation

“…25,26 Conversely, if there is less than 1 cm between the edge of the placenta and the os, the chances of hemorrhage are so high as to warrant planned cesarean delivery. 26,27 The optimal management of patients with between 1.0 and 2.0 cm between the os and the placenta is uncertain (Fig. 3).…”

Using ultrasound in the clinical management of placental implantation abnormalities

“…As compared to those with cervical os to placental edge distance between 11-20 mm, patients with internal cervical os to placental edge distance 10 mm have high rates of antepartum hemorrhage (29% vs 3%; odds ratio, 11.5; 95% confidence interval, 1.6e76.7) 13 and cesarean delivery rates 73-91% vs 24-40%. 10,13,14 However, there are no significant differences in the gestational ages at delivery between the 2 groups and 75-80% of these patients are delivered at term. 13 The thickness of the lower placental edge has also been evaluated as a predictor of bleeding in patients with marginal/low-lying placentas.…”

“…20 In women with low-lying placenta (cervical os to placental edge distance 20 mm), cervical length has been studied as a predictor of antepartum bleeding and indicated preterm birth. 10,[12][13][14] It was found that short cervix ( 25 mm) was associated with higher rates of antepartum bleeding (75% vs 31%; P ¼ .02), blood transfusion (25% vs 3%; P ¼ .02), lower birthweight (62% vs 17%; P ¼ .02), and neonatal intensive care unit admissions (50% vs 17%; P ¼ .04). 22 Figure 3 is a proposed guideline for managing asymptomatic patients with marginal or low-lying placenta based on published literature that has used internal cervical os to placental edge distance cutoffs of <1, 1-2, and >2 cm; placental edge thickness cutoff of 1 cm; and cervical length cutoff of 25 mm.…”

“…Low-lying placenta is diagnosed when the distance between the internal cervical os and the placental edge is 1-20 mm. [9][10][11][12][13][14]22,23 If the distance between the internal cervical os and the placental edge is >20 mm, the patients should be managed as per routine because the overwhelming majority of studies have not demonstrated an increased risk for cesarean delivery due to hemorrhage. [9][10][11][12][13] Due to the normal process of "placental migration" as the lower uterine segment matures, the ultrasound examination may be repeated in the third trimester to identify those patients who can be allowed to go to term vs those who are at increased risk for antepartum hemorrhage and preterm delivery, and therefore need to be carefully watched.…”