Association between placental location and cord insertion site with pre-eclampsia: a retrospective cohort study

OBJECTIVE

The relationship between placental location in pregnancies without previa and adverse pregnancy outcomes has not been well studied. Additionally, the impact of abnormal cord insertion sites remains controversial. Therefore, the objective of this study was to explore the adverse outcomes associated with placental location and abnormal cord insertion in nulliparous women and to assess their impact on pregnancy outcomes.

METHODS

This retrospective cohort study was conducted at a single tertiary hospital between January 2019 and June 2022. The study included nulliparous women with singleton pregnancies who delivered live infants and had available data on placental location and umbilical cord insertion site from a second- or third-trimester ultrasound. Placental location was categorized as anterior or posterior using transabdominal ultrasonography. The association between placental location/cord insertion site and pre-eclampsia was evaluated using multivariate logistic regression analysis. We compared the area under the curve to evaluate the impact of placental location and cord insertion site on pre-eclampsia.

RESULTS

A total of 2219 pregnancies were included in the study. Pre-eclampsia occurred significantly more frequently in the anterior group than in the posterior group (8.21% vs. 3.04%, p < .001). In multivariate analysis investigating the association between placental location and pre-eclampsia, anterior placenta and marginal cord insertion showed increased odds ratios for pre-eclampsia of 3.05 (95% confidence interval [CI] 1.68-6.58) and 3.64 (95% CI 1.90-6.97), respectively. Receiver operating characteristic (ROC) curves were constructed to predict pre-eclampsia using independent factors from multivariate analyses. Model I, including maternal age, pre-pregnancy body mass index, in vitro fertilization, chronic hypertension, overt diabetes, kidney disease, and hematologic diseases, achieved an area under the ROC curve of 0.70 (95% CI 0.65-0.75). Adding cord insertion site and placental location to the model (Model II) improved its predictive performance, resulting in an area under the ROC curve of 0.749 (95% CI 0.70-0.79, p = .02).

CONCLUSIONS

Anterior placenta and marginal cord insertion were associated with an increased risk of pre-eclampsia. Further studies on prospective cohorts are necessary to validate these findings.

Relationship between placental location and fetal gender using ultrasonography: A prospective study from the Maternity and Children's Hospital, Najran, Saudi Arabia

The study was a prospective cross-sectional design and was carried out at the Maternity and Children's Hospital in Najran, Saudi Arabia on 142 pregnant women . The objective of the study was to establish, utilising ultrasound scan , whether there is any link between the site of the placenta and the gender of the fetus. A higher percentage of female fetuses were identified. The majority of placentas (73, 51.4%) were found to be anterior, of which 66 (46.5%) and 7 (4.9%) were present in female and male fetuses, respectively. 58 (40.8%) placentas were noted to be posterior, i.e. females, 10 (7.0%); males, 48 (33.8%). 10 (7.0%) placentas were high, a position which was equally prevalent in both genders, i.e. females, 5 (3.5%); males 5 (3.5%), and 1 (0.7%), in a male fetus, was low-lying. A significant correlation between placental site and the gender of the fetus was revealed by the chi-squared test (p < 0.05) the sensitivity of ultrasound in predication fetal gendar was 95.1%. The outcome reveals a noteworthy association between the position of the placenta and the gender of the fetus.

A Cross-Sectional Study to Evaluate the Impact of Placental Location on Maternal and Fetal Outcomes

Background The human placenta is a critical organ for facilitating nutrient uptake, waste elimination, and gaseous exchange between the mother and the fetus. In the placenta, there are two circulations, namely, maternal and fetal. The blood supply of the placenta is not uniformly distributed as the maternal circulation, determined by uterine blood supply, depends on the implantation site. The uterine blood supply plays a significant role in placental blood flow and pregnancy success. Hence, abnormalities in the placental implantation may affect the placenta's blood supply, leading to adverse maternal and fetal outcomes. This study aims to examine the relationship between placental location and maternofetal outcomes. Methodology This cross-sectional study was conducted in the Department of Obstetrics & Gynaecology at Bijapur Lingayat District Educational Association (Deemed to be University), Shri B. M. Patil Medical College, Hospital and Research Centre, Vijayapura, from January 2021 to April 2022. A total of 1,301 patients were included in this study. Results There was a positive and significant association between fundal implantation and severe preeclampsia and premature rupture of membranes. There was a positive and significant association between left lateral implantation and severe preeclampsia. The histopathological changes seen in the histopathological report of the fetal surface of the placenta also had a positive and significant association with the fundal location of the placenta. Conclusions This study suggests that fundal left lateral placentation leads to abnormal results. Such patients can be considered high risk and should be given meticulous antenatal care, depending on placental location at the 28-week ultrasonography.

The use of magnetic resonance imaging to predict placenta previa with placenta accreta spectrum

INTRODUCTION

Massive hemorrhage due to placenta previa with placenta accreta spectrum is associated with high maternal mortality and morbidity. Therefore, accurate prediction of placenta previa with placenta accreta spectrum is essential; magnetic resonance imaging (MRI) is a useful tool for this purpose. This study investigated novel predictors of anterior and posterior placenta previa with placenta accreta spectrum using MRI.

MATERIAL AND METHODS

This was a retrospective study at a tertiary obstetrics hospital in Japan. The singleton patients with placenta previa who were scanned with MRI prenatally and had a cesarean section at our institution between 2007 and 2018 were included. The prediction of anterior and posterior placenta previa with placenta accreta spectrum was evaluated using four MRI findings: heterogeneous signals in the placenta, dark T2-weighted intraplacental bands, myometrial thinning or interruption, and focal uterine bulging. The prediction of posterior placenta previa with placenta accreta spectrum was performed using the quantification of cervical varicosities, which were defined as the ratio of the distance between the minimum distance from the most dorsal cervical varicosities (a) to the deciduous and amniotic placenta (b) on a sagittal image.

RESULTS

Among 202 patients, 14 (6.9%) patients were pathologically diagnosed as having placenta accreta spectrum. Further, 38 (18.8%) patients had anterior placenta previa and 164 (81.2%) patients had posterior placenta previa. When anterior placenta previa with placenta accreta spectrum was predicted using at least one of the four MRI findings, the sensitivity and specificity of the anterior placenta previa with placenta accreta spectrum were 87.5% and 86.7%, respectively. In contrast, the sensitivity and specificity of posterior placenta previa with placenta accreta spectrum were 42.9% and 96.2%, respectively. But when the A/B ratio was set at 0.20, the sensitivity and specificity of the prediction for posterior placenta previa with placenta accreta spectrum using cervical varicosities were 100.0% and 89.2%, respectively.

CONCLUSIONS

The findings of MRI to predict the anterior placenta previa with placenta accreta spectrum were different from posterior placenta previa. The cervical varicosities may be useful in predicting posterior placenta previa with placenta accreta spectrum.

Placental location and risk of retained placenta in women with a previous cesarean section: A population-based cohort study

INTRODUCTION

Some studies have shown that women with a previous cesarean section, compared with women with a previous vaginal delivery, have an increased risk of retained placenta during a subsequent vaginal delivery. It is unknown whether this is mediated by anterior placental location, when the placenta might cover the uterine scar. The aim of this study was to evaluate whether the increased risk of retained placenta in women with a previous cesarean section is mediated by anterior placental location.

MATERIAL AND METHODS

This is a population-based cohort study, with data from the regional population-based Stockholm-Gotland Obstetric Cohort, Sweden, from 2008 to 2014. The overall study population included 49 598 women with a vaginal second delivery, where adequate information about placental location from the second-trimester ultrasound scan was available. For the main analysis, including the 3921 women with a previous cesarean section, we calculated the relative risk of retained placenta in women with an anterior placental location, using women with non-anterior placental locations as reference. Relative risks were calculated as odds ratios (OR) with 95% CI. In a second model, adjustments were made for maternal age, height, country of birth, smoking in early pregnancy, infant sex, and in vitro fertilization.

RESULTS

In the overall study population, the rate of retained placenta at the second delivery was 2.0%. The proportion of women with a retained placenta was higher among women with a previous cesarean compared with those with a previous vaginal delivery (3.4% vs 1.9%; P < .0001). In the main analysis, including women with a previous cesarean section, the risk for retained placenta was not increased with anterior compared with non-anterior placental location (OR 0.84, 95% CI 0.60-1.20). Adjustments did not affect the estimates in a significant way.

CONCLUSIONS

The increased risk of retained placenta in women with a previous cesarean section is not mediated by anterior placental location.

The effect of placental location in cases of placenta accreta spectrum

BACKGROUND

Placenta accreta spectrum affects approximately 3 in 1000 pregnancies. There is a paucity of data evaluating the effect of placental location on diagnosis, risk factors, and resultant outcomes in cases of placenta accreta spectrum.

OBJECTIVE

We analyzed placenta accreta spectrum cases to assess whether risk factors or maternal outcomes varied based on placental location.

MATERIALS AND METHODS

We performed a retrospective chart review of pathology-confirmed cases of placenta accreta spectrum from patients delivering at 2 large urban hospitals in the same healthcare system from 2007 to 2017. Placental location was defined by ultrasound images and confirmed by pathology reports. Location was categorized as anterior, posterior, or anterior/posterior for those with placental location at both sites. Fisher exact tests and analysis of variance were used to examine associations with measures of diagnosis, risk factors, and maternal outcomes.

RESULTS

A total of 86 pathology-confirmed placenta accreta spectrum cases were reviewed. The distribution of placental location on ultrasound was as follows: 19% posterior, 59% anterior, and 22% anterior/posterior. We found that prior cesarean delivery was lower with posterior placenta accreta spectrum (63% vs 94% vs 84% in the anterior and anterior/posterior groups respectively; (P = .007); however, in vitro fertilization rates were significantly higher (38% vs 2% vs 5% in the anterior and anterior/posterior groups respectively; P = .001). There was also lower incidence of percreta with posterior placenta accreta spectrum compared to the anterior and anterior/posterior groups (19% vs 47% vs 58% respectively; P = .055). Posterior cases were less likely to have placenta accreta spectrum suspected prenatally (50%) compared to anterior (80%) and anterior/posterior (89%) cases (P = .019). Despite late diagnosis, ureteral injury was the only surgical complication that was more common in patients with posterior placenta accreta spectrum (13% vs 0% vs 5% for anterior and anterior/posterior groups respectively; P = .037).

CONCLUSION

Placenta accreta spectrum with posterior placental location is associated with delayed diagnosis, surgical complications, assisted reproductive technology, and lower numbers of prior cesarean deliveries relative to anterior location. These differences in outcomes and risk factors based on placental location may allow for heightened clinical awareness, and improved diagnosis and management.

Placental location and pregnancy outcomes in nulliparous women: A population-based cohort study

INTRODUCTION

The impact of placenta previa on pregnancy, delivery and infant outcomes has been extensively studied. However, less is known about the possible association of placental location other than previa with pregnancy outcomes. The aim of this study was to investigate if placental location other than previa is associated with adverse pregnancy, delivery and infant outcomes.

MATERIAL AND METHODS

This is a population-based cohort study, with data from the regional population-based Stockholm-Gotland Obstetric Cohort, Sweden, from 2008 to 2014. The study population included 74 087 nulliparous women with singleton pregnancies resulting in live-born infants, with information about placental location from the second-trimester ultrasound screening. The association between placental location (fundal, lateral, anterior or posterior) and pregnancy outcomes was estimated using logistic regression analysis. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated, and adjustments were made for maternal age, height, country of birth, smoking in early pregnancy, sex of the infant and in vitro fertilization. Main outcome measures were pregnancy, delivery and infant outcomes.

RESULTS

Compared with posterior placental location, fundal and lateral placental locations were associated with a number of adverse pregnancy outcomes, the most important being: very preterm birth (<32 weeks of gestation) (adjusted OR [aOR] 1.78, 95% CI 1.18-2.63 and aOR 2.12, 95% CI 1.39-2.25, respectively), moderate preterm birth (32-36 weeks of gestation) (aOR 1.23, 95% CI 1.001-1.51 and aOR 1.62, 95% CI 1.32-2.00, respectively), small-for-gestational-age birth (aOR 1.67, 95% CI 1.34-2.07 and aOR 1.77, 95% CI 1.39-2.25, respectively) and manual removal of the placenta in vaginal births (aOR 3.27, 95% CI 2.68-3.99 and aOR 3.27, 95% CI 2.60-4.10, respectively). Additionally, lateral placental location was associated with preeclampsia (aOR 1.30, 95% CI 1.03-1.65) and severe postpartum hemorrhage (aOR 1.42, 95% CI 1.27-1.82).

CONCLUSIONS

Compared with posterior placental location, fundal and lateral placental locations are associated with a number of adverse pregnancy, delivery and infant outcomes.

Placental Location and the Development of Hypertensive Disorders of Pregnancy

OBJECTIVES

Abnormal placentation is an important factor in the pathogenesis of preeclampsia. As a result of diminished blood flow, the incidence of preeclampsia might be higher in patients with laterally located placentas compared to patients with centrally located placentas. The objective of this study was to evaluate the relationship between placental location and the development of hypertensive disorders of pregnancy.

METHODS

Patients with singleton pregnancies who were seen in our ultrasound unit and delivered at our institution from October 2014 to April 2015 were included. The incidence of hypertensive disorders was compared in those with a lateral placental location and those with centrally located placentas (placental locations other than lateral). Baseline characteristics and pregnancy outcomes were compared between groups. The χ² test, Fisher exact test, Mann-Whitney U test, and t test were used when appropriate. P < .05 was considered significant.

RESULTS

We included 464 patients; 411 (88.57%) had centrally located placentas, and 53 (11.42%) had laterally located placentas. The incidence of hypertensive disorders of pregnancy was similar between groups (21% versus 19%; P = .71). Gestational age at delivery (P = .73), and small for gestational age (P = .96) were also similar between our study groups.

CONCLUSIONS

In our study, there was no difference in the rate of hypertensive disorders of pregnancy between patients with central and laterally located placentas.

Pathophysiology of placental-derived fetal growth restriction

Placental-related fetal growth restriction arises primarily due to deficient remodeling of the uterine spiral arteries supplying the placenta during early pregnancy. The resultant malperfusion induces cell stress within the placental tissues, leading to selective suppression of protein synthesis and reduced cell proliferation. These effects are compounded in more severe cases by increased infarction and fibrin deposition. Consequently, there is a reduction in villous volume and surface area for maternal-fetal exchange. Extensive dysregulation of imprinted and nonimprinted gene expression occurs, affecting placental transport, endocrine, metabolic, and immune functions. Secondary changes involving dedifferentiation of smooth muscle cells surrounding the fetal arteries within placental stem villi correlate with absent or reversed end-diastolic umbilical artery blood flow, and with a reduction in birthweight. Many of the morphological changes, principally the intraplacental vascular lesions, can be imaged using ultrasound or magnetic resonance imaging scanning, enabling their development and progression to be followed in vivo. The changes are more severe in cases of growth restriction associated with preeclampsia compared to those with growth restriction alone, consistent with the greater degree of maternal vasculopathy reported in the former and more extensive macroscopic placental damage including infarcts, extensive fibrin deposition and microscopic villous developmental defects, atherosis of the spiral arteries, and noninfectious villitis. The higher level of stress may activate proinflammatory and apoptotic pathways within the syncytiotrophoblast, releasing factors that cause the maternal endothelial cell activation that distinguishes between the 2 conditions. Congenital anomalies of the umbilical cord and placental shape are the only placental-related conditions that are not associated with maldevelopment of the uteroplacental circulation, and their impact on fetal growth is limited.

Is lateral localisation of placenta a risk factor for adverse perinatal outcomes?

The aim of this study was to evaluate the relationship between placental localisation and perinatal outcomes. This study was performed in a tertiary centre hospital by retrospectively analysing the medical records of patients who were followed up and underwent delivery in the same hospital. The patients were divided into two groups according to the placental locations (central and lateral) in their routine sonographic findings between the 18 and 24 weeks' gestation. Out of 1,057 patients, 87.4% (n = 919) had centrally located placentas and 12.6% (n = 133) had laterally located placentas. Preeclampsia was found to be significantly higher in the lateral placental location group (4.5% vs. 1.6%; p = 0.027). There was a significant correlation with foetal growth restriction (FGR), preterm birth rates, low Apgar scores and need for neonatal intensive care unit in the lateral placental location group (p < 0.05). The pregnant women with laterally located placentas should be followed up promptly with special care for the risk of preeclampsia and FGR, and poor neonatal outcomes.