The risk of placenta accreta following primary elective caesarean delivery: 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.

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.

Placenta Accreta Spectrum: The Role of Interventional Radiology in Multidisciplinary Management

Placenta accreta spectrum is increasing in prevalence and poses significant risks to obstetric patients. This article defines characteristics, diagnosis, management, and outcomes of placenta accreta spectrum, highlighting interventional radiology's role in its management as part of a multidisciplinary approach.

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.

Placenta Percreta Managed by Ultrasound-Guided Vertical Transfundal Uterine Incision with Hysterectomy: Case Report

Placenta accreta spectrum is an obstetrics complication in which the placenta has abnormally adhered to the decidua and uterine wall. Placenta percreta is the rarest and sternest variant of accreta syndrome. In this study, we present a case of placenta percreta where we have done ultrasound-guided trans fundal vertical uterine incision to deliver a healthy fetus and subsequent cesarean hysterectomy. Antepartum diagnosis, involvement of a multidisciplinary team, appropriate counseling of women and their families, ultrasound guidance for placental margin demarcation, and vertical transfundal uterine incision can be considered for patients with placenta percreta.

Life After Amsterdam: Placental Pathology Consensus Recommendations and Beyond

The Amsterdam Placental Workshop Group Consensus Statement on Sampling and Definitions of Placental Lesions has become widely accepted and is increasingly used as the universal language to describe the most common pathologic lesions found in the placenta. This review summarizes the most salient aspects of this seminal publication and the subsequent emerging literature based on Amsterdam definitions and criteria, with emphasis on publications relating to diagnosis, grading, and staging of placental pathologic conditions. We also provide an overview of the recent expert recommendations on the pathologic grading of placenta accreta spectrum, with insights on their clinical context. Finally, we discuss the emerging entity of SARS-CoV2 placentitis.

Prospective Evaluation of the Ultrasound Signs Proposed for the Description of Uterine Niche in Nonpregnant Women

OBJECTIVES

To evaluate the new ultrasound-based signs for the diagnosis of post-cesarean section uterine niche in nonpregnant women.

METHODS

We investigated prospectively a cohort of 160 consecutive women with one previous term cesarean delivery (CD) between December 2019 and 2020. All women were separated into two subgroups according to different stages of labor at the time of their CD: subgroup A (n = 109; 68.1%) for elective CD and CD performed in latent labor at a cervical dilatation (≤4 cm) and subgroup B (n = 51; 31.9%); for CD performed during the active stage of labor (>4 cm).

RESULTS

Overall, the incidence of a uterine niche was significantly (P < .001) higher in women who had an elective (20/45; 44.4%) compared with those who had an emergent (21/115; 18.3%) CD. Compared with subgroup B, subgroup A presented with a significantly (P = .012) higher incidence of uterine niche located above the vesicovaginal fold and with a significantly (P = .0002) lower proportion of cesarean scar positioned below the vesicovaginal fold. There was a significantly (P < .001) higher proportion of women with a residual myometrial thickness (RMT) > 3 mm in subgroup A than in subgroup B and a significant negative relationship was found between the RMT and the cervical dilatation at CD (r = -0.22; P = .008).

CONCLUSIONS

Sonographic cesarean section scar assessment indicates that the type of CD and the stage of labor at which the hysterotomy is performed have an impact on the location of the scar and the scarification process including the niche formation and RMT.

The Risk of Postpartum Hemorrhage Following Prior Prelabor Cesarean Delivery Stratified by Abnormal Placentation: A Multicenter Historical Cohort Study

Background: Prior prelabor cesarean delivery (CD) was associated with an increase in the risk of placenta previa (PP) in a second delivery, whether it may impact postpartum hemorrhage (PPH) independent of abnormal placentation. This study aimed to assess the risk of PPH stratified by abnormal placentation following a first CD before the onset of labor (prelabor) or intrapartum CD.

Methods: This multicenter, historical cohort study involved singleton, pregnant women at 28 weeks of gestation or greater with a CD history between January 2017 and December 2017 in 11 public tertiary hospitals within 7 provinces of China. PPH was analyzed in the subsequent pregnancy between women with prior prelabor CD and women with intrapartum CD. Furthermore, PPH was analyzed in pregnant women stratified by complications with PP alone [without placenta accreta spectrum (PAS) disorders], complications with PP and PAS, complications with PAS alone (without PP), and normal placentation. We performed multivariate logistic regression to calculate adjusted odds ratios (aOR) and 95% CI controlling for predefined covariates.

Results: Out of 10,833 pregnant women, 1,197 (11%) women had a history of intrapartum CD and 9,636 (89%) women had a history of prelabor CD. Prior prelabor CD increased the risk of PP (aOR 1.91, 95% CI 1.40–2.60), PAS (aOR 1.68, 95% CI 1.11–2.24), and PPH (aOR 1.33, 95% CI 1.02–1.75) in a subsequent pregnancy. After stratification by complications with PP alone, PP and PAS, PAS alone, and normal placentation, prior prelabor CD only increased the risk of PPH (aOR 3.34, 95% CI 1.35–8.23) in a subsequent pregnancy complicated with PP and PAS.

Conclusion: Compared to intrapartum CD, prior prelabor CD increased the risk of PPH in a subsequent pregnancy only when complicated by PP and PAS.

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.

Do you pay to go private?: a single centre comparison of induction of labour and caesarean section rates in private versus public patients

Background

The aim of this study was to compare rates of induction and subsequent caesarean delivery among nulliparous women with private versus publicly funded health care at a single institution. This is a retrospective cohort study using the electronic booking and delivery records of nulliparous women with singleton pregnancies who delivered between 2010 and 2015 in an Irish Tertiary Maternity Hospital (approx. 9000 deliveries per annum).

Methods

Data were extracted from the National Maternity Hospital (NMH), Dublin, Patient Administration System (PAS) on all nulliparous women who delivered a liveborn infant at ≥37 weeks gestation during the 6-year period. At NMH, all women in spontaneous labour are managed according to a standardised intrapartum protocol. Twenty-two thousand two hundred thirty-two women met the inclusion criteria. Of these, 2520 (12.8%) were private patients; the remainder (19,712; 87.2%) were public. Mode of and gestational age at delivery, rates of and indications for induction of labour, rates of pre-labour caesarean section, and maternal and neonatal outcomes were examined. Rates of labour intervention and subsequent maternal and neonatal outcomes were compared between those with and without private health cover.

Results

Women attending privately were more than twice as likely to have a pre-labour caesarean section (12.7% vs. 6.5%, RR = 2.0, [CI 1.8–2.2])); this finding persisted following adjustment for differences in maternal age and body mass index (BMI) (adjusted relative risk 1.74, [CI 1.5–2.0]). Women with private cover were also more likely to have induction of labour and significantly less likely to labour spontaneously. Women who attended privately were significantly more likely to have an operative vaginal delivery, whether labour commenced spontaneously or was induced.

Conclusions

These findings demonstrate significant differences in rates of obstetric intervention between those with private and public health cover. This division is unlikely to be explained by differences in clinical risk factors as no significant difference in outcomes following spontaneous onset of labour were noted. Further research is required to determine the roots of the disparity between private and public decision-making. This should focus on the relative contributions of both mothers and maternity care professionals in clinical decision making, and the potential implications of these choices.

Etiopathogenesis and risk factors for placental accreta spectrum disorders

Placenta accreta spectrum (PAS) disorders, comprising placenta accreta, increta, and percreta, are associated with serious maternal morbidity and mortality in both the developed and the developing world. The incidence of PAS has increased in the recent years, and the rising rates of cesarean section rate, placenta accreta in previous pregnancies, and other uterine surgeries including myomectomies and repeated endometrial curettage are implicated in its etiopathogenesis. The absolute risk of PAS increases with the number of previous cesarean sections. The PAS remains undiagnosed in one-half to two-thirds of cases, thus increasing maternal morbidity and mortality. Understanding etiopathogenesis and risk factors of this condition allows early diagnosis and planning of delivery, and thereby would help improve maternal and fetal outcomes.

Development of placental abnormalities in location and anatomy

Low‐lying placentas, placenta previa and abnormally invasive placentas are the most frequently occurring placental abnormalities in location and anatomy. These conditions can have serious consequences for mother and fetus mainly due to excessive blood loss before, during or after delivery. The incidence of such abnormalities is increasing, but treatment options and preventive strategies are limited. Therefore, it is crucial to understand the etiology of placental abnormalities in location and anatomy. Placental formation already starts at implantation and therefore disorders during implantation may cause these abnormalities. Understanding of the normal placental structure and development is essential to comprehend the etiology of placental abnormalities in location and anatomy, to diagnose the affected women and to guide future research for treatment and preventive strategies. We reviewed the literature on the structure and development of the normal placenta and the placental development resulting in low‐lying placentas, placenta previa and abnormally invasive placentas.

Understanding Factors Leading to Primary Cesarean Section and Vaginal Birth After Cesarean Delivery in the Friuli-Venezia Giulia Region (North-Eastern Italy), 2005-2015

Although there is no evidence that elevated rates of cesarean sections (CS) translate into reduced maternal/child perinatal morbidity or mortality, CS have been increasingly overused almost everywhere, both in high and low-income countries. The primary cesarean section (PCS) has become a major driver of the overall CS (OCS) rate, since it carries intrinsic risk of repeat CS (RCS) in future pregnancies. In our study we examined patterns of PCS, pl compared with planned TOLAC anned PCS (PPCS), vaginal birth after 1 previous CS (VBAC-1) and associated factors in Friuli Venezia Giulia (FVG), a region of North-Eastern Italy, collecting data from its 11 maternity centres (coded from A to K) during 2005-2015. By fitting three multiple logistic regression models (one for each delivery mode), we calculated the adjusted rates of PCS and PPCS among women without history of CS, whilst the calculation of the VBAC rate was restricted to women with just one previous CS (VBAC-1). Results, expressed as odds ratio (OR) with 95% confidence interval (95%CI), were controlled for the effect of hospital, calendar year as well as several factors related to the clinical and obstetric conditions of the mothers and the newborn, the obstetric history and socio-demographic background. In FVG during 2005-2015 there were 24,467 OCS (rate of 24.2%), 19,565 PCS (19.6%), 7,736 PPCS (7.7%) and 2,303 VBAC-1 (28.4%). We found high variability of delivery mode (DM) at hospital level, especially for PCS and PPCS. Breech presentation was the strongest determinant for PCS as well as PPCS. Leaving aside placenta previa/abuptio placenta/ante-partum hemorrhage, further significant factors, more importantly associated with PCS than PPCS were non-reassuring fetal status and obstructed labour, followed by (in order of statistical significance): multiple birth; eclampsia/pre-eclampsia; maternal age 40-44 years; placental weight  600-99 g; oligohydramios; pre-delivery LoS 3-5 days; maternal age 35-39 years; placenta weight 1,000-1,500 g; birthweight < 2,000 g; maternal age ≥ 45 years; pre-delivery LoS ≥ 6 days; mother's age 30-34 years; low birthweight (2,000-2,500 g); polyhydramnions; cord prolaspe; ≥6 US scas performed during pregnancy and pre-term gestations (33-36 weeks). Significant factors for PPCS were (in order of statistical significance): breech presentation; placenta previa/abruptio placenta/ante-partum haemorrhage; multiple birth; pre-delivery LoS ≥ 3 days; placental weight ≥ 600 g; maternal age  40-44 years; ≥6 US scans performed in pregnancy; maternal age ≥ 45 and 35-39 years; oligohydramnios; eclampsia/pre-eclampsia; mother's age 30-34 years; birthweight <2,000 g; polyhydramnios and pre-term gestation (33-36 weeks). VBAC-1 were more likely with gestation ≥ 41 weeks, placental weight <500 g and especially labour analgesia. During 2005-2015 the overall rate of PCS in FVG (19.6%) was substantially lower than the corresponding figure reported in 2010 for the entire Italy (29%) and still slightly under the most recent national PCS rate for 2017 (22.2%). The VBAC-1 rate on women with history of one previous CS in FVG was 28.4% (25.3% considering VBAC on all women with at least 1 previous CS), roughly three times the Italian national rate of 9% reported for 2017. The discrepancy between the OCS rate at country level (38.1%) and FVG's (24.2%) is therefore mainly attributable to RCS. Although there was a marginal decrease of PCS and PPCS crudes rates over time in the whole region, accompained by a progressive enhancement of the crude VBAC rate, we found remarkable variability of DM across hospitals. To further contain the number of unnecessary PCS and promote VBAC where appropriate, standardized obstetric protocols should be introduced and enforced at hospital level. Decision-making on PCS should be carefully scrutinized, introducing a diagnostic second opinion for all PCS, particularly for term singleton pregancies with cephalic presentation and in case of obstructed labour as well as non-reassuring fetal status, grey areas potentially affected by subjective clinical assessment. This process of change could be facilitated with education of staff/patients by opinion leaders and prenatal counseling for women and partners, although clinical audits, financial penalties and rewards to efficient maternity centres could also be considered.

Placental complications in subsequent pregnancies after prior cesarean section performed in the first versus second stage of labor

OBJECTIVE

To examine whether prior cesarean delivery (CD) in the first stage of labor (non-progressive labor in the first stage - NPL1), when compared with CD in the second stage of labor (non-progressive labor in the second stage - NPL2), is associated with different rates of third stage placental complications in the subsequent delivery.

METHODS

A retrospective cohort study, of all deliveries following a CD due to NLP1 or NLP2 that occurred between the years 1988 and 2013, was undertaken. Multiple gestation pregnancies, known uterine malformations or uterine fibroids were excluded. Rates of third stage complications (retained placenta, adherent/increta/percreta placenta, manual removal of the placenta) were compared between the groups. Univariate analysis was followed by multivariate analysis.

RESULTS

During the study period, there were 3828 subsequent deliveries of parturients who were operated due to NPL1 and NPL2 (72.91 and 27.09%, respectively). Rates of manual removal of the placenta as well as adherent placenta were significantly higher among parturients following CD due to NPL2 (28.4 versus 24.0%, p = .04, 1.2 versus 0.4% p < .01, respectively). In a multivariate analysis controlling for possible confounders, adherent placenta was found to be independently associated with vaginal delivery following CD due to NPL2 (odds ratio 2.98, 95% confidence interval 1.30-6.77).

CONCLUSIONS

Prior CD due to NPL2 as opposed to NPL1 is independently associated with adherent placenta in the subsequent delivery. A higher index of suspicion may be needed when evaluating these women during pregnancy as well as during management of the delivery.

The Placenta Accreta Spectrum: Epidemiology and Risk Factors

The placenta accreta spectrum has become an important contributor to severe maternal morbidity. The true incidence is difficult to ascertain, but likely falls near 1/1000 deliveries. This number seems to have increased along with the rate of risk factors. These include placenta previa, previous cesarean section, use of assisted reproductive technologies, uterine surgeries, and advanced maternal age. With increased uterine conservation, previous retained placenta or placenta accreta have become significant risk factors. Understanding placenta accreta spectrum risk factors facilitates patient identification and safe delivery planning. Patients considering elective uterine procedures or delayed childbirth should consider the impact on peripartum morbidity.

The effectiveness of prophylactic internal iliac artery balloon occlusion in the treatment of patients with pernicious placenta previa coexisting with placenta accreta

Aim: This study aimed to explore the therapeutic effectiveness of prophylactic internal iliac artery balloon occlusion (IIABO) during cesarean delivery in the management of patients with pernicious placenta previa (PPP) coexisting with placenta accreta (PA).Methods: This retrospectively study enrolled 83 patients diagnosed with PPP coexisting with PA in our hospital between January 2014 and December 2017. The patients were divided into the study group (n = 58, receiving routine cesarean section followed prophylactic IIABO) and control group (n = 25, receiving routine cesarean section alone). The general situation, intraoperative conditions, maternal and neonatal outcomes, and postoperative complications between the two groups were compared.Results: The two groups were comparable due to no significant difference in the general situation of patients. The intraoperative conditions, such as intraoperative and postoperative blood loss, transfusion volume and the incidence rate of transfusion in the study group were significantly lower than those in the control group, but the incidence rate of disseminated intravascular coagulation and hysterectomy did not exhibit significant differences. Moreover, maternal and neonatal outcomes were not significantly different. Besides, in the study group, a patient with left foot numbness appeared left popliteal artery thrombosis and four patients experienced fever of <38.5 °C and lower abdominal pain. In the control group, a patient underwent hysterectomy.Conclusions: Prophylactic IIABO is an alternative method to control postpartum hemorrhage in the treatment of PPP coexisting with PA. However, it may not decrease the incidence of hysterectomy.

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.

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

Background

Cesarean section (CS) is an independent risk factor for placenta accreta. Some researchers think that the timing of primary cesarean delivery is associated with placenta accreta in subsequent pregnancies. The aim of this study was to investigate the risk of placenta accreta following primary CS without labor, also called primary elective CS, in a pregnancy complicated with placenta previa.

Methods:

A retrospective, single-center, case-control study was conducted at Peking University Third Hospital. Relevant clinical data of singleton pregnancies between January 2010 and September 2017 were recorded. The case group included women with placenta accreta who had placenta previa and one previous CS. Control group included women with one previous CS that was complicated with placenta previa. Maternal age, body mass index, gestational age, fetal birth weight, gravity, parity, induced abortion, the rate of women received assisted reproductive technology, other uterine surgery, and primary elective CS were analyzed between the two groups.

Results:

The rate of primary elective CS (90.1% vs. 69.9%, P < 0.001) was higher, and maternal age was younger (32.7 ± 4.7 years vs. 34.6 ± 4.0 years, P < 0.001) in case group, compared with control group. Case group also had higher gravity and induced abortions compared with the control group (both P < 0.05). Primary CS without labor was associated with significantly increased risk of placenta accreta in a subsequent pregnancy complicated with placenta previa (odds ratio: 3.32; 95% confidential interval: 1.68-6.58).

Conclusion:

Women with a primary elective CS without labor have a higher chance of developing an accreta in a subsequent pregnancy that is complicated with placenta previa.

Risk factors for abnormally invasive placenta: a systematic review and meta-analysis

Purpose of the article. To explore the strength of association between different maternal and pregnancy characteristics and the occurrence of abnormally invasive placenta (AIP).Materials and methods: Pubmed, Embase, CINAHL databases were searched. The risk factors for AIP explored were: obesity, age >35 years, smoking before or during pregnancy, placenta previa, prior cesarean section (CS), placenta previa and prior CS, prior uterine surgery, abortion and uterine curettage, in vitro fertilization (IVF) pregnancy and interval between a previous CS, and a subsequent pregnancy. Random-effect head-to-head meta-analyses were used to analyze the data.Results: Forty-six were included in the systematic review. Maternal obesity (Odd ratio, OR: 1.4, 95% CI 1.0-1.8), advanced maternal age (OR: 3.1, 95% CI 1.4-7.0) and parity (OR: 2.5, 95% CI 1.7-3.6), but not smoking were associated with a higher risk of AIP. The presence of placenta previa in women with at least a prior CS was associated with a higher risk of AIP compared to controls, with an OR of 12.0, 95% CI 1.6-88.0. Furthermore, the risk of AIP increased with the number of prior CS (OR of 2.6, 95% CI 1.6-4.4 and 5.4, 95% CI 1.7-17.4 for two and three prior CS respectively). Finally, IVF pregnancies were associated with a high risk of AIP, with an OR of 2.8 (95% CI 1.2-6.8).Conclusion: A prior CS and placenta previa are among the strongest risk factors for the occurrence of AIP.

The risk of placenta accreta following primary cesarean delivery

OBJECTIVE

To (a) evaluate the risk for placenta accreta following primary cesarean section (CS), in regard to the stage of labor, the cesarean section was taken (elective prelabor vs. unplanned during labor); and (b) investigate whether the association between placenta accreta and maternal and neonatal complications is modified by the type of the primary CS.

STUDY DESIGN

In a population-based retrospective cohort study, we included all singleton deliveries occurred in Soroka University Medical Center between 1991 and 2015, of women who had a history of a single CS. The deliveries were divided into three groups according to the delivery stage the primary CS was carried out: 'Unplanned 1' (first stage-up to 10 cm), 'Unplanned 2' (second stage-10 cm) and 'Elective' prelabor CS. We assessed the association between the study group and placenta accreta using logistic generalized estimation equation (GEE) models. We additionally assessed maternal and neonatal complications associated with placenta accreta among women who had elective and unplanned CS separately.

RESULTS

We included 22,036 deliveries to 13,727 women with a history of one CS, of which 0.9% (n = 207) had placenta accreta in the following pregnancies: 12% (n = 25) in the 'Unplanned 1' group, 7.2% (n = 15) in the ' Unplanned 2' group and 80.8% (n = 167) in the 'elective' group. We found no difference in the risk for subsequent placenta accreta between the groups. In a stratified analysis by the timing of the primary cesarean delivery, the risk for maternal complications, associated with placenta accreta, was more pronounced among women who had an unplanned CS (OR 27.96, P < 0.01) compared to women who had an elective cesarean delivery (OR 13.72, P < 0.01).

CONCLUSIONS

The stage in which CS is performed has no influence on the risk for placenta accreta in the following pregnancies, women who had an unplanned CS are in a higher risk for placenta accrete-associated maternal complications. This should be taken into consideration while counselling women about their risk while considering trial of labor after cesarean section.

Histopathology of Placenta Creta: Chorionic Villi Intrusion into Myometrial Vascular Spaces and Extravillous Trophoblast Proliferation are Frequent and Specific Findings With Implications for Diagnosis and Pathogenesis

Placenta creta is characterized by invasion of placental villi into the myometrium in the setting of a dysfunctional or absent decidua. Histopathologic diagnosis of placenta creta is important, particularly in cases of hysterectomy because of unanticipated intractable postpartum hemorrhage. Previous studies have documented a higher amount and depth of myometrial infiltration by the implantation site intermediate trophoblast compared with controls. In addition, we have anecdotally observed chorionic villi in myometrial vascular spaces in specimens with placenta creta. The aim of this study was to explore the prevalence and specificity of these features. Sixty-one postpartum hysterectomies, 44 with placenta creta and 17 without were reviewed. Villous intrusion into vascular spaces was recorded. Using immunohistochemistry for GATA3, the amount of intermediate trophoblast (number of positive cells in five 40× fields) and depth of trophoblast myometrial infiltration were assessed. Mean gestational ages of the creta group (34.4 yr; range, 20-43 yr) and control group (35 yr; range, 25-51 yr) were comparable. Presence of chorionic villi in myometrial vascular spaces was frequent in placenta creta: 31/44 versus 1/17 controls (70.4% vs. 5.8%, P<0.0001). This finding was more common in the percreta (87.5%) and increta (84%) than in the accreta (27.2%, P=0.0008). Mean depth of trophoblast myometrial invasion was greater in cretas (47.9%) than in controls (14.5%, P=0.004). Likewise, mean distance of deepest trophoblast to serosa was shorter in the cretas (7.3 mm) than in controls (23.8 mm, P<0.0001). These differences were, however, attributable to placentas increta and percreta. When only accretas and controls were compared, the myometrial depth of trophoblast was similar. The mean intermediate trophoblast cell count in the placental bed was greater in cretas (664) than in controls (288, P<0.0001). Such difference was seen in all creta cases despite the type (accreta 639, increta 676, percreta 661). A trophoblast count of ≥100 cells/high-power field was seen in 75.8% of cretas and 11.1% of controls (P=0.0009). For the first time, we document the finding of chorionic villi intrusion into myometrial vascular spaces, which is highly specific of placenta creta. In addition, assessment of the amount of intermediate trophoblast using GATA3 immunohistochemistry can assist in the diagnosis. We hypothesize that placental invasion in placenta creta is due, at least partially, to transformation of low-resistance myometrial vessels leading to subsequent protrusion of villi into their lumens, in the context of absent decidua.

Maternal complications in settings where two-thirds of extremely preterm births are delivered by cesarean section

OBJECTIVE

To investigate the maternal complications associated with cesarean section (CS) in the extremely preterm period according to the gestational week (GW) and to indication of delivery.

STUDY DESIGN

This is a retrospective case-referent study with a review of medical records of women who delivered at 22-27 weeks of gestation (n=647) at two level III units in Sweden. For abdominal delivery, gestational length was stratified into 22-24 (n=105) and 25-27 (n=301) weeks. For comparison, data on women who underwent a CS at term were identified in a register-based database.

RESULTS

The rate of CS in extremely preterm births was 62.8%. There was no difference in the complication rates, but types of incisions other than the low transverse incision were required more often at 22-24 (18.1%) weeks than at 25-27 GWs (9.6%) (P=0.02). Major maternal complications occurred in 6.6% compared with 2.1% in the extremely preterm and term CS, respectively (P<0.01). A maternal indication of extremely preterm CS increased the risk of complications.

CONCLUSIONS

Almost two-thirds of the births at 22-27 GWs had an abdominal delivery. No increase in short-term morbidity was observed at 22-24 weeks compared to 25-27 weeks. CS performed extremely preterm had more major complications recorded than cesarean at term. The complications are driven by the underlying maternal condition.

Breech delivery at a University Hospital in Tanzania

Background

There is a global increase in rates of Cesarean delivery (CD). A minor factor in this increase is a shift towards CD for breech presentation. The aim of this study was to analyze breech births by mode of delivery and investigate short-term fetal and maternal outcomes in a low-income setting.

Methods

The study design was cross-sectional and the setting was Muhimbili National Hospital (MNH), Dar-es-Salaam, Tanzania. Subjects were drawn from a clinical database (1999–2010) using the following inclusion criteria: breech presentation, birth weight ≥ 2,500 g, single pregnancy, fetal heart sound at admission, and absence of pregnancy-related complication as indication for CD. Of 2,765 mothers who had a breech delivery, 1,655 met the inclusion criteria. Analyses were stratified by mode of delivery, taking into account also other birth characteristics. The outcome measures were perinatal death (stillbirths + in-hospital neonatal deaths) and moderate asphyxia. Maternal outcomes, such as death, hemorrhage, and length of hospital stay, were also described.

Results

The CD rate for breech presentation increased from 28 % in 1999 to 78 % in 2010. Perinatal deaths were associated with vaginal delivery (VD) (adjusted odds ratio (aOR) 6.2; 95 % confidence interval (CI) 3.0–12.6) and referral (aOR 2.1; 95 % CI 1.1–3.9), but not with parity, birth weight, or delivery year. Overall perinatal mortality was 5.8 % and this did not decline, due to an increase in stillbirths among vaginal breech deliveries. Mothers with CD had more hemorrhage compared to those with VD. One mother died in association with CD, and one died in association with VD.

Conclusion

A breech VD, compared to a breech CD, in this setting was associated with adverse perinatal outcome. However, despite a significant increase in CD rate, no overall improvement was observed due to an increase in stillbirths among VDs.

Confirmed severe maternal morbidity is associated with high rate of preterm delivery

BACKGROUND

Because severe maternal morbidity (SMM) is increasing in the United States, affecting up to 50,000 women per year, there was a recent call to review all mothers with SMM to better understand their morbidity and improve outcomes. Administrative screening methods for SMM have recently been shown to have low positive predictive value for true SMM after chart review. To ultimately reduce maternal morbidity and mortality we must better understand risk factors, and preventability issues about true SMM such that interventions could be designed to improve care.

OBJECTIVE

Our objective was to determine risk factors associated with true SMM identified from California delivery admissions, including the relationship between SMM and preterm delivery.

STUDY DESIGN

In this retrospective cohort study, SMM cases were screened for using International Classification of Diseases, Ninth Revision codes for severe illness and procedures, prolonged postpartum length of stay, intensive care unit admission, and transfusion from all deliveries in 16 hospitals from July 2012 through June 2013. Charts of screen-positive cases were reviewed and true SMM diagnosed based on expert panel agreement. Underlying disease diagnosis was determined. Women with true-positive SMM were compared to SMM-negative women for the following variables: maternal age, ethnicity, gestational age at delivery, prior cesarean delivery, and multiple gestation.

RESULTS

In all, 491 women had true SMM and 66,977 women did not have SMM for a 0.7% rate of true SMM. Compared to SMM-negative women, SMM cases were significantly more likely to be age >35 years (33.6 vs 23.8%; P < .0001), be African American (14.1 vs 7.9%; P < .0001), have had a multiple gestation (9.7 vs 2.1%; P < .0001), and, for the multiparous women, have had a prior cesarean delivery (58 vs 30.2%; P < .0001). Preterm delivery was significantly more common in SMM women compared to SMM-negative women (41 vs 8%; P < .0001), including delivery <32 weeks (18 vs 2%; P < .0001). The most common underlying disease was obstetric hemorrhage (42%) followed by hypertensive disorders (20%) and placental hemorrhage (14%). Only 1.6% of women with SMM had cardiovascular disease as the underlying disease category.

CONCLUSION

An extremely high proportion of women with severe morbidity (42.5%) delivered preterm with 17.8% delivering <32 weeks, which underscores the importance of access to appropriate-level care for mothers with SMM and their newborns. Further, the extremely high rate of preterm delivery (75%) in women with placental hemorrhage in combination with their 63% prior cesarean delivery rate highlights another risk of prior cesarean delivery: subsequent preterm delivery. These data provide a reminder that a cesarean delivery could be a contributing factor to not only hemorrhage-related SMM, but also to increased subsequent preterm delivery, more reason to continue national efforts to safely reduce initial cesarean deliveries.