Effect of Primary Elective Cesarean Delivery on Placenta Accreta: A Case-Control Study

Development and validation of a nomogram for predicting placenta accreta spectrum in pregnancies with one previous cesarean delivery

OBJECTIVE

This study aimed to develop and validate a prenatal nomogram to predict the risk of placenta accreta spectrum (PAS) in women with one previous cesarean delivery.

METHODS

This retrospective study enrolled 5157 pregnant women with one previous cesarean delivery in China from January 2021 to January 2023. The nomogram was developed from a training cohort of 3612 pregnant women and tested on a validation cohort of 1545 pregnant women. Multivariate regression analysis was performed using the minimum value of the Akaike information criterion to select prognostic factors that can be included in the nomogram. We evaluated the nomogram by the area under the receiver operating characteristic (ROC) curve, calibration curves, and the decision curve analysis (DCA).

RESULTS

PAS occurred in 199 (5.51%) and 80 (5.18%) patients in the training and validation cohorts, respectively. Backward stepwise algorithms in the multivariable logistic regression model determined abortion, hypertensive disorders complicating pregnancy, fetal position, and placenta previa as relevant PAS predictors. The area under the ROC curve for the nomogram was 0.770 (95% confidence interval [CI] 0.733-0.807) and 0.791 (95% CI 0.730-0.853) for the training and validation cohorts, respectively. The calibration curves indicated that the nomogram's prediction probability was consistent with the actual probability. The DCA curve revealed that the nomogram has potential clinical benefit.

CONCLUSION

A prenatal nomogram was developed for PAS in our study, which helped obstetricians determine potential patients with PAS and make sufficient preoperative preparation to reduce maternal and neonatal complications.

Placenta accreta outcomes and risk factors in a referral hospital in north of Iran: A case control study

Background

Placenta accreta syndrome (PAS) may led to heavy blood loss and maternal death. Here we analyzed the main risk factors of PAS+ pregnancies and its complications in a referral hospital in the north of Iran.

Methods

In a case control study, all pregnant women with PAS referred to our department during 2016 till 2021 were enrolled and divided in two groups case (PAS+) and control (PAS-) based on preoperative imaging, intraoperative findings, and pathological reports. The sociodemographic features and neonatal-maternal outcomes also were recorded.

Results

The most frequent reason for cesarean (C/S) was repeated C/S (62.9%, 56/89). A significant difference showed up in the time lag between previous C/S and the present delivery (p < 0.001) which shows that when the time distance is longer, the risk of PAS rises (OR: 1.01 [95% CI: 1.003-1.017]). Also, a positive history of prior abortion and elective type of previous C/S were related to PAS+ pregnancies. Our other finding showed that PAS+ pregnancies will end in lower gestational age and have a longer duration of operation and hospitalization, heavy blood transfusion, and hysterectomy. Also, PAS+ pregnancies were not related to poor neonatal outcomes.

Conclusions

It seems that, in addition to repeated C/S as a strong risk factor, previous abortion is a forgotten key which leads to incomplete evacuation or damage the endometrial-myometrial layers.

Clinical Risk Factors for Placenta Accreta or Placenta Percreta: A Case-Control Study

OBJECTIVES

Uterine scarring is a risk factor for placenta accreta spectrum (PAS) disorder. We aimed to determine the factors related to PAS in women who had previously undergone a cesarean.

METHODS

We performed a case-control study where women who underwent postpartum hysterectomy for placenta accreta/percreta (cases) were matched to all women with a previous cesarean who delivered in the week before each case (controls). Maternal characteristics along with previous cesarean characteristics were compared between cases and controls. Univariate and multivariate logistic regression analyses were performed to determine risk factors related to PAS.

RESULTS

We compared 64 cases of PAS that required hysterectomy to 192 controls. The factors related to PAS were a history of uterine surgery (OR 27.4; 95% CI 5.1-146.5, P < 0.001) and the number of previous cesareans (2 cesareans: OR 7.2; 95% CI 3.4-15.4, P < 0.001; more than 2 cesareans: OR 7.9; 95% CI 2.9-21.5, P < 0.001). In women with a single previous cesarean without previous uterine surgery, an interdelivery interval of fewer than 18 months (OR 6.3; 95% CI 1.8-22.4, P = 0.004) and smoking (OR 5.8; 95% CI 1.2-27.8, P = 0.03) were related to PAS. The gestational age and the cervical dilatation at previous cesarean were not associated with PAS (all with P > 0.05). The lack of data regarding the closure of the uterus at previous cesareans prevents us from drawing solid conclusions.

CONCLUSIONS

Previous uterine surgery, the number of previous cesareans, smoking, and an interdelivery interval of fewer than 18 months after cesarean are significant risk factors for PAS requiring postpartum hysterectomy.

Effect of cervical changes on the cesarean scar area and niche formation after preterm and term cesarean sections

OBJECTIVE

The purpose of this study is to assess the scar area and niche formation after cesarean section in women who had preterm or term deliveries and underwent cesarean section at various stages of labor.

METHOD

This prospective cohort study consists of cases who underwent the first cesarean section for different obstetric reasons. The patients were divided into four groups regarding gestational age and cervical dilatation. After a cesarean section, all patients were called for vaginal ultrasonography control at 12 weeks. The location of the scar and the presence of a niche were evaluated. The residual (RMT), proximal, and distal myometrial thicknesses were evaluated where the scar and niche were located.

RESULTS

A total of 87 cases were included in the study. There was no difference in the prevalence of niche between the groups (p > 0.05). RMT and proximal and distal myometrial thickness were not different between the 37 ≥ week and 37 < week groups, while RMT and proximal and distal myometrial thickness were significantly lower in women with active labor (p =0.001, p= 0.006, p =0.016). The location of the scar was the isthmus at 37 weeks and above (p= 0.002), it was in the cervical canal in the group below 37 weeks (p= 0.017).

CONCLUSION

The gestational week and cervical changes did not affect the prevalence of the niche. In cases of active labor and preterm deliveries, the CS scar defect was located in the cervical canal; however, in cases of term deliveries, it was located in the isthmic area.

The prenatal diagnostic indicators of placenta accreta spectrum disorders

Placenta accreta spectrum (PAS) disorders refers to a heterogeneous group of anomalies distinguished by abnormal adhesion or invasion of chorionic villi through the myometrium and uterine serosa. PAS frequently results in life-threatening complications, including postpartum hemorrhage and hysterotomy. The incidence of PAS has increased recently as a result of rising cesarean section rates. Consequently, prenatal screening for PAS is essential. Despite the need to increase specificity, ultrasound is still considered a primary adjunct. Given the dangers and adverse effects of PAS, it is necessary to identify pertinent markers and validate indicators to improve prenatal diagnosis. This article summarizes the predictors regarding biomarkers, ultrasound indicators, and magnetic resonance imaging (MRI) features. In addition, we discuss the effectiveness of joint diagnosis and the most recent research on PAS. In particular, we focus on (a) posterior placental implantation and (b) accreta after in vitro fertilization-embryo transfer, both of which have low diagnostic rates. At last, we graphically display the prenatal diagnostic indicators and each diagnostic performance.

Fentanyl for labour pain management: a scoping review

BACKGROUND

Labour pain has been identified as an important reason for women to prefer caesarean section (CS). Fentanyl is one of the short acting opioids recommended by World Health Organization for pain relief during labour. This study aimed to identify and describe the available evidence on the use of fentanyl (monotherapy) for labour pain management by any routes of administration or regime.

METHODS

We included the records published until 31 December 2021 which reported administration of fentanyl to women with normal labour for labour pain relief. Data were extracted by one reviewer and checked by another reviewer using a standardised agreement form. We mapped and presented data descriptively in figure and tabular format.

RESULTS

We included 51 records from 49 studies in our scoping review. The studies were conducted in 12 countries, mostly high-income countries. The study designs of the 51 included records were varied as follows: 38 (74.5%) experimental studies (35 randomised controlled trials and three quasi-experimental studies), and 12 (23.5%) observational studies (five retrospective cohort studies, four prospective cohort studies, two retrospective descriptive studies, and one descriptive study) and one qualitative study. Of the included records, six used intranasal fentanyl, five used subcutaneous fentanyl, 18 (35.3%) used intravenous fentanyl, 18 (35.3%) used intrathecal fentanyl, and nine used epidural fentanyl. Many records compared fentanyl with another analgesic agent while five records (9.8%) had no comparison group and seven records (13.7%) compared with no analgesia group. The doses of fentanyl varied by routes, study and the requirement depended on the women. Pain assessment was the most frequent outcome measure presented in the records (78.4%). Only nine records (17.6%) investigated women's satisfaction about labour pain relief using fentanyl and seven records (13.7%) reported the effect of fentanyl on breastfeeding. The most common reported neonatal outcomes were foetal heart rate (33 records, 64.7%) and Apgar score (32 records, 62.7%).

CONCLUSION

There is limited primary evidence especially randomised controlled trials to evaluate the effectiveness and harms of different routes of fentanyl in low- or middle-income countries. There is a need for high-quality research to establish the most effective route of fentanyl and associated effects for evidence-based international guidelines.

Evidence around early induction of labor in women of advanced maternal age and those using assisted reproductive technology

Worldwide, there has been a trend toward later motherhood. Concurrently, the incidence of subfertility has been on the rise, necessitating conception using assisted reproductive technologies (ARTs). These pregnancies are considered high risk due to fetal complications such as antepartum stillbirth and growth restriction and maternal complications such as increase in maternal morbidity and mortality. Early induction of labor can help to mitigate these risks. However, this has to be balanced against the iatrogenic harms of earlier delivery to both the baby, including respiratory distress and NICU stay, and the mother who might experience longer labor and other complications such as uterine hyperstimulation. Induction of labor at 39 weeks is the optimal timing for preventing antepartum stillbirth and avoiding iatrogenic harm. Delivery by elective cesarean section is not advocated as its benefits in these patients are unclear compared with the short- and long-term complications of a major abdominal surgery.

A 5-year experience on perinatal outcome of placenta accreta spectrum disorder managed by cesarean hysterectomy in southern Iranian women

Background

We aimed to investigate the risk factors of placenta accreta spectrum (PAS) disorder, management options and maternal and neonatal outcomes of these pregnancies in a resource-limited clinical setting.

Methods

All women diagnosed with placenta accreta, increta, and percreta who underwent peripartum hysterectomy using a multidisciplinary approach in a tertiary center in Shiraz, southern Iran between January 2015 until October 2019 were included in this retrospective cohort study. Maternal variables, such as estimated blood loss, transfusion requirements and ICU admission, as well as neonatal variables such as, Apgar score, NICU admission and birthweight, were among the primary outcomes of this study.

Results

A total number of 198 pregnancies underwent peripartum hysterectomy due to PAS during the study period, of whom163 pregnancies had antenatal diagnosis of PAS. The mean gestational age at the time of diagnosis was 26 weeks, the mean intra-operative blood loss was 2446 ml, and an average of 2 packs of red blood cells were transfused intra-operatively. Fifteen percent of women had surgical complications with bladder injuries being the most common complication. Furthermore, 113 neonates of PAS group were admitted to NICU due to prematurity of which 15 (7.6%) died in neonatal period.

Conclusion

Our findings showed that PAS pregnancies managed in a resource-limited setting in Southern Iran have both maternal and neonatal outcomes comparable to those in developed countries, which is hypothesized to be due to high rate of antenatal diagnosis (86.3%) and multidisciplinary approach used for the management of pregnancies with PAS.

The effect of the onset of labor on the characteristics of the cesarean scar

OBJECTIVE

To assess the effect of cesarean section (CS) timing, elective versus unplanned, on the residual myometrial thickness (RMT) and CS scars.

METHODS

This is a prospective single-blinded observational cohort study with 186 observations. Patients indicated to undergo first singleton CS were preoperatively recruited. Exclusion criteria were history of repeated CS, vertical hysterotomy, diabetes, and additional uterine surgeries. Sonographic examination was performed for assessing the RMT ratio, the presence of a niche, fibrosis, and the distance from the scar to the internal os (SO) 1 year after CS. Power analysis was performed with 0.05 α, 0.1 β, and all statistical analyses were conducted with Stata^® .

RESULTS

Wilcoxon rank-sum test for the association between CS timing, RMT ratio and SO showed Z values of -0.59 and -4.94 (P = 0.553 and P < 0.001), respectively. There was no association between CS timing and niches and fibrosis (P > 0.99 and P = 0.268, respectively). Linear regression between SO and the extent of cervical dilatation showed a -0.45 β (95% confidence interval -0.68 to -0.21) and a 10.22-mm intercept (P < 0.001).

CONCLUSION

RMT is independent of the timing of CS, but the SO distance shows a negative linear relationship with the cervical dilatation.

Position and integrity of uterine scar are determined by degree of cervical dilatation at time of Cesarean section

OBJECTIVE

Abnormal placental invasion is more common after an elective Cesarean delivery, suggesting that prelabor Cesarean section (CS) increases the likelihood of the CS scar being above the internal cervical os and predisposing to a scar pregnancy in the future. The aim of this study was to assess the location and integrity of the CS scar in postpartum women delivered by CS at different stages of labor.

METHODS

This was a prospective cohort study of women at term who underwent a CS for the first time. In all women, cervical dilatation was determined by digital examination at the time of the CS. All patients had a transvaginal ultrasound examination to assess the location of the CS scar in relation to the internal cervical os, as well as the presence of a scar niche.

RESULTS

A total of 407 pregnant women were recruited into the study: 103 with cervical dilatation ≤ 2 cm, 261 with cervical dilatation 3-7 cm and 43 with cervical dilatation ≥ 8 cm at the time of the CS. A statistically significant correlation was observed between cervical dilatation at the time of the CS and the position of the CS scar. The scar was positioned in the uterus above the internal cervical os in 97.1% (100/103) of women delivered at a cervical dilatation of 0-2 cm, whereas the scar was located at or below the internal cervical os in 97.7% (42/43) of cases delivered at a cervical dilatation of 8-10 cm (P < 0.001). A uterine-scar defect (niche) was observed in 38.1% (64/168) of women with the scar located above, compared with 18.0% (43/239) of those with the scar situated at or below, the internal cervical os (P < 0.001).

CONCLUSIONS

Prelabor and early-labor Cesarean delivery are associated with an increased prevalence of a scar in the uterine cavity as well as a scar niche. CS in late labor is associated with the uterine scar being situated in the endocervical canal and with a lower incidence of a niche. The position and integrity of the CS scar after prelabor and early-labor Cesarean delivery explain the predisposition to abnormal placental invasion in subsequent pregnancy. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Does delivery in private hospitals contribute largely to Caesarean Section births? A path analysis using generalised structural equation modelling

BACKGROUND

The rate of Caesarean Section (CS) deliveries has shown an alarming rise in recent years. CS is a surgical procedure used when there is apprehension of risk to the life of mother or baby in case of vaginal delivery, but its rates higher than 10-15 per cent are not justifiable. It is well recognised that a CS delivery could have a large number of adverse impacts on women and infants. Several studies, especially in developing countries, have revealed that delivery in private hospitals is one of the most contributing factors in CS deliveries. The present study conceptualises a causal pathway in which the possible risk factors, socio-economic, maternal and pregnancy-related, as well as institutional, influence the chances of CS delivery. It is hypothesised that certain factors would contribute to CS deliveries largely indirectly through the place of delivery, that is, either a public or private institution.

METHODS AND FINDINGS

To test the hypotheses, this study analysed 146,280 most recent live births delivered in hospitals during the five years preceding the fourth round of India's National Family Health Survey (NFHS-4), carried out during 2015-2016. The analysis, using generalised structural equation modelling (GSEM), revealed that many exogenous variables considered in the path models influence CS deliveries significantly, directly and/or indirectly through the place of delivery factor. Prominent among these are wealth index and receiving ANC services at only private hospitals; the total effects of these variables are even higher than the direct/total effect of place of delivery.

CONCLUSION

From this finding, it could be said that the place of delivery is a proximate determinant of a CS delivery or a mediator of other co-factors. Interventions to curb higher CS deliveries should be focused on improving the quality of public health sectors and on developing protocols for CS deliveries.

Influencing factors for placenta accreta in recent 5 years: a systematic review and meta-analysis

Objective: Assess influencing factors for placenta accreta in pregnant women documented in recent literature.Methods: A systematic review and meta-analysis were conducted based on English- and Chinese-language articles published from January 2014 to June 2019. Articles were retrieved from the following Chinese databases, CNKI, Wanfang Data, China Science and Technology Journal Database, CBM and English databases, PubMed, Web of Science, the Cochrane Library and Embase.Results: Eleven studies with 2,152,014 cases were included in the meta-analysis. The odds ratios of influencing factors were as follows: hypertension 2.51 (95% CI, 1.50-4.20), multifetal gestations 1.90 (95% CI, 1.26-2.88), male fetus 0.79 (95% CI, 0.74-0.84), and low socioeconomic status 0.51 (95% CI, 0.37-0.71).Conclusion: Evidence from English- and Chinese-language literature indicates that hypertension and multifetal gestations are risk factors for placenta accreta, while male fetus and low socioeconomic status are protective factors.

Cesarean section does not affect neonatal outcomes of pregnancies complicated with preterm premature rupture of membranes

BACKGROUND

Preterm premature rupture of membranes (PPROM) is associated with high neonatal morbidity and mortality. However, the influences of cesarean section (CS) on neonatal outcomes in preterm pregnancies complicated with PPROM are not well elucidated. The aim of this study was to investigate the influence of delivery modes on neonatal outcomes among pregnant women with PPROM.

METHODS

A retrospective cross-sectional study was conducted in 39 public hospitals in 14 cities in the mainland of China from January 1st, 2011 to December 31st, 2011. A total of 2756 singleton pregnancies complicated with PPROM were included. Adverse neonatal outcomes including early neonatal death, birth asphyxia, respiratory distress syndrome (RDS), pneumonia, infection, birth trauma, and 5-min/10-min Apgar scores were obtained from the hospital records. Binary variables and ordinal variables were respectively calculated by binary logistic regressions and ordinal regression. Numerical variables were compared by multiple linear regressions.

RESULTS

In total, 2756 newborns were involved in the analysis. Among them, 1166 newborns (42.31%) were delivered by CS and 1590 newborns belonged to vaginal delivery (VD) group. The CS proportion of PPROM obviously increased with the increase of gestational age (χ = 5.014, P = 0.025). Compared with CS group, VD was associated with a higher risk of total newborns mortality (odds ratio [OR], 2.38; 95% confidence interval [CI], 1.102-5.118; P = 0.027), and a lower level of pneumonia (OR, 0.32; 95% CI, 0.126-0.811; P = 0.016). However, after multivariable adjustment and stratification for gestational age, only pneumonia was significantly related with CS in 28 to 34 weeks group (OR, 0.34; 95% CI, 0.120-0.940; P = 0.038). There were no differences regarding to other adverse outcomes in the two groups, including neonatal mortality, birth asphyxia, Apgar scores, RDS, pneumonia, and sepsis.

CONCLUSIONS

The proportion of CS of pregnant women with PPROM was very high in China. The mode of delivery does not affect neonatal outcomes of pregnancies complicated with PPROM.

The risk of abnormal placentation and hemorrhage in subsequent pregnancy following primary elective cesarean delivery

Objective: We aimed to evaluate the relationship between mode of first delivery with subsequent placenta previa, placenta accreta/increta, and significant postpartum hemorrhage (PPH).Method: This retrospective cohort study included women with two consecutive singleton deliveries between 2007 and 2017 at our institution if the women were nulliparous and delivered at term at the time of first delivery. The first pregnancy delivery mode was classified as (1) vaginal delivery, (2) antepartum cesarean delivery (CD) without labor, or (3) intrapartum CD after the onset of labor. Within these three groups, rates of placenta previa, placenta accreta/increta, and significant PPH at the time of the second delivery were compared. Significant PPH was defined as hemorrhage requiring a blood transfusion.Results: A total of 8208 women were analyzed. Most first deliveries were vaginal (n = 5210, 63.5%), followed by antepartum CD (n = 2432, 29.6%) and intrapartum CD (n = 566, 6.9%). The incidence of placenta previa in subsequent deliveries differed by previous delivery mode: vaginal, 0.9%; antepartum CD, 2.0%; intrapartum CD, 1.6% (p < .001). Similar differences were also observed with respect to placenta accreta/increta (0.5 versus 1.5 versus 0.9%, p < .001) and PPH (0.6 versus 1.2 versus 0.4%, p = .017). Compared to the previous vaginal delivery group, the antepartum CD group had increased risks of placenta previa (aORs 2.02, 95% CI 1.35-3.05), placenta accreta/increta (aOR 2.52; 95% CI 1.53-4.14) and PPH (aOR 1.78, 95% CI 1.14-2.98) in subsequent pregnancies. However, the previous intrapartum CD was not significantly associated with increased risks of these complications.Conclusion: Previous antepartum CD was associated with two-fold increased risks of placenta previa, placenta accreta/increta, and significant PPH in the second delivery compared to women with a prior vaginal delivery. The increased risks of subsequent abnormal placentation following primary antepartum CD may be important for counseling concerning nonmedically indicated elective cesarean.Condensation: Previous antepartum cesarean delivery (CD) was associated with two-fold increased risks of placenta previa, placenta accreta/increta, and significant PPH in the second delivery.