Intracervical Lakes as A Sonographic Marker of Placenta Accreta Spectrum (PAS) in Patients with Previa and Low-Lying Placenta; A Prospective Observational Study

Abstract

SUMMARY he novel finding of this study introduces a new ultrasound sign, intracervical lakes (ICL), associated with placenta accreta spectrum disorder in women with placenta previa or low-lying placenta, which potentially represents a marker of deep villus invasion. Presence of ICL seems to be an independent predictor of placenta percreta and its incorporation into ultrasound examination may increase the diagnostic accuracy for Cesarean hysterectomy and major postpartum hemorrhage in women with placenta previa or low-lying placenta. The purpose of the present study was to evaluate the role of a new ultrasound sign, named intracervical lakes (ICL), in predicting the presence of PAS disorder and delivery outcome in patients with placenta previa or low-lying placenta. This was a prospective observational study of 110 women with placenta previa or low-lying placenta at ≥36 weeks gestation, who were referred to Ain Shams Maternity Hospital between January 2021and December 2021. Demographic characteristics of the studied cases in which mean±SD of age 30.2±2.6 (years), BMI 30.6±2.6 (Kg/m2), gestational age 36.7±0.6 (weeks) and previous cesarean section median (1st- 3rd IQ) 3.0 (2.0–4.0). PAS signs were found in 51cases of the studied cases. Intracervical Lakes was found 26 cases of the studied cases, all cases with Intracervical Lakes had positive PAS sign. PAS diagnosis finally confirmed in 56 of cases with percentage 50.9 % of the studied cases, while placenta percreta finally confirmed in 21 cases with percentage of 19.1 % the studied cases. Antepartum hemorhage was the most frequent maternal complication; detected in 61 cases with percentage of 55.5 % of the studied cases. As regard Diagnostic characteristics of radiological findings in preedicting PAS, PAS had moderate diagnostic characteristics with sensitivity 76.8 % and specificity 85.2 %,while PAS sign+ Intracervical Lakes increased specificity to 98.1 %, positive predictive value 96.2 %, LR+ 24.11 % and DOR 42.74, but decreased other characteristics. As regaed Diagnostic characteristics of radiological findings in predicting percreta PAS sign had high sensitivity 95.2 %& NPV 98.3 %, and moderate other diagnostic characteristics, PAS sign+ Intracervical Lakes not markedly decreased sensitivity 90.5 %& NPV 97.6 %, but markedly increased other diagnostic characteristic with specificity 92.1%. As regard Diagnostic characteristics of radiological findings in predicting antepartum hemorrhage PAS sign had moderate diagnostic characteristics in predicting antepartum hemorrrhage, with sensitivity 72.1 % and specificity 85.7 %, while PAS sign+ Intracervical Lakes increased specificity 95.9%, positive predictive value 92.3 %, LR+ 9.64 and DOR 15.24, but decreased other characteristics. As regard Diagnostic characteristics of radiological findings in predicting severe bleeding PAS sign had moderate diagnostic characteristics in predicting severe bleeding with sensitivity 83.3 % and specificity 58.2 % while, PAS sign+ Intracervical Lakes increased specificity 80.6%, positive predictive value 26.9 %, LR+ 3.1 and DOR 5,82, but decreased other characteristics. As regard Diagnostic characteristics of radiological findings in predicting hysterectomy, PAS sign had high sensitivity 95.5 %& NPV 98.3 %, and moderate other diagnostic characteristics, PAS sign+ Intracervical Lakes not markedly decreased sensitivity 90.9 %& NPV 97.6%, but markedly increased other diagnostic characteristics with specificity 93.2 %. As regard Diagnostic characteristics of radiological findings in predicting postpartum hemorrhage PAS sign had low diagnostic characteristics in predicting postpartum hemorrhage, with sensitivity 58.8% and specificity 55.9% while PAS sign+ Intracervical Lakes increased specificity 78.5%, positive predictive value 23.1%, LR+ 1.64 and DOR 1.99, but decreased other characteristics. The following study is in agree with our study Di Pasquo et al. first published at March (2019). This was a retrospective multicenter study of a total number 332 women with placenta previa or low-lying placenta at ≥ 26 weeks' gestation, who were referred to three Italian tertiary units from January 2015 to September 2018. No other studies published in the same topic against our results. Strengths and limitations The main strengths of this study was prospective study in, inclusion of consecutive patients, evaluation of different clinical outcomes and assessment of the ultrasound images by expert examiners in the prenatal diagnosis of PAS disorder, and intraoperative observation which was done by expert obstetrician. Other studies were retrospective assessment of ICL and the lack of evaluation of the intra- and interobserver variability of the explored signs represent the major weaknesses of these studies. The limitation of the study is Inclusion of only women affected by placenta previa or low-lying placenta represents another limitation of the study. A significant proportion of PAS disorders have been shown to occur in women with no recognizable risk factors for these anomalies. Other limitation is small number of sample size 110 cases and the outbreak of COVID 19. In this scenario, the findings from this study are applicable only to women presenting with placenta previa or low-lying placenta. In this preliminary study, the number and distribution of the ICL were not assessed because our main outcome was to assess the clinical significance of this new sign and to assess its association with the risk of PAS disorder.