Introduction

In recent years, there has been a notable increase in the occurrence of placenta previa and Placenta Accreta Spectrum (PAS) conditions. This rise is largely attributed to the higher rates of cesarean deliveries, assisted reproductive technologies, and various uterine interventions such as septum resection, myomectomy, and lysis of intracavitary bands. Placenta previa is estimated to affect 1 in 500 pregnancies, while PAS is believed to occur in 1 in 400 to 1 in 1500 pregnancies. It's important to recognize that patient factors, particularly previous uterine surgeries, can significantly impact these rates. Ultrasonography remains the most reliable method for detecting low-lying placentas and placenta previas, although they are often discovered during routine fetal anatomical scans in the second trimester. Studies suggest that up to 91% of placenta previas identified during the midtrimester will resolve by delivery. Placental thickness has garnered attention, with research showing associations with growth abnormalities, postpartum hemorrhage, and PAS in the middle and third trimesters. However, the clinical significance of placental thickness is still being explored, particularly in the context of placenta previa. Placentas were categorized as thick, thin, or average based on their thickness relative to our cohort's mean and standard deviation. The primary aim was to determine if mid-trimester placental thickness correlated with persistence of placenta previa at birth, aiming to enhance patient counseling and decision-making. During the study period, 400 pregnancies with mid-trimester placenta previa were identified. Of these, 14.2% had thin placentas, 85.5% had average placentas, and 19.32% had thick placentas. Patients with thick placenta previas tended to be older, have a history of prior cesarean delivery, possess a fibroid uterus, deliver at an earlier gestational age, and undergo pathologic assessment of the placenta.

Placental thickness

Placental thickness was positively associated with the number of prior cesarean deliveries. Our findings suggest that midtrimester placental thickness may provide insights into the persistence of placenta previa, aiding in clinical decision-making. Further research is warranted to validate these observations and elucidate the clinical implications fully. The standard midtrimester ultrasound protocol typically involves examining the placental location without measuring its thickness. In cases where placenta previa is diagnosed, additional images and video clips are taken to provide more detailed information. While routine transvaginal sonography is used, it often doesn't capture the thickest part of the placenta for thickness assessment as per our study protocol. Therefore, we retrospectively analyzed transabdominal images of placenta previa while previous studies have looked at placental thickness in the second trimester, standardized measurements specifically for mid-trimester placenta previa have not been established.

Examine the persistence

Thus, we used the mean and standard deviations from our cohort, which displayed a relatively normal distribution. The main focus of our study was to examine the persistence of placenta previa at the time of delivery. Typically, patients with this condition undergo delivery between 36 and 37 weeks of gestation at our institution. However, the decision on the timing of delivery depends on various factors such as the presence of other health issues or bleeding, and is made by the obstetrical and maternal-fetal medicine teams. We also looked into other outcomes including postpartum hemorrhage, cesarean delivery, placenta accreta spectrum, and a combination of maternal complications. Management of postpartum hemorrhage followed guidelines from the American College of Obstetricians and Gynecologists. We conducted a retrospective review of patient charts, extracting relevant clinical data from the electronic medical records. Statistical analysis included various tests such as chi-square, There were no significant differences in baseline characteristics such as race, insurance status, body mass index, nulliparity, use of in vitro fertilization (IVF), history of myomectomy or dilation and curettage, or gestational age at diagnosis based on placenta previa thickness. Although placental thickness measured at 20 weeks versus 28 weeks would vary significantly, the timing of diagnosis and measurement did not differ between the groups. Additionally, there was a positive correlation between placenta previa thickness and the number of previous cesarean deliveries.