Key Takeaways
- At specialized centers, maternal survival rates exceed 99% — the key is being at the right hospital with the right team
- Prenatal diagnosis reduces blood loss, transfusion needs, and maternal morbidity compared to being undiagnosed at delivery
- Neonatal outcomes are generally good, with most complications related to planned preterm delivery
- Future fertility is possible with conservative approaches, though subsequent pregnancies carry elevated risks
Introduction
Placenta Accreta Spectrum carries significant risks regardless of the treatment approach chosen. There is no risk-free option. The goal is to choose the approach that minimizes overall risk given your individual circumstances — the depth of invasion, the desired number of future pregnancies, the experience of the surgical team, and the hospital's resources.
All data on this page comes from published, peer-reviewed medical studies. Sources are cited throughout and listed in full at the bottom of the page. Where data ranges are given, they reflect variation across studies, institutions, and PAS severity.
One factor overwhelmingly improves outcomes: an experienced multidisciplinary team (MDT) at a center of excellence. The difference between expert and non-expert care is the single largest determinant of survival and complication rates.
Expert centers report near-zero maternal mortality (0.05–0.25%). Nationally, mortality for PAS can reach 7%. The difference is not subtle — it is the difference between life and death. WHERE you are treated may be the single most important decision you make.[1][2]
How Prior C-Sections Increase PAS Risk
The single most important risk factor for PAS is a prior cesarean delivery combined with placenta previa. Each additional C-section compounds the risk. A cesarean delivery triples the risk of PAS in the next pregnancy compared to a vaginal birth.14
| Number of Prior C-Sections | PAS Risk WITHOUT Previa | PAS Risk WITH Previa |
|---|---|---|
| 1 | 0.2% | 3% |
| 2 | 0.3% | 11% |
| 3 | 0.6% | 40% |
| 4 | 2.1% | 61% |
| 5 | 2.3% | 67% |
| 6 | 6.7% | — |
Data from: Jauniaux et al., Nature Reviews Disease Primers 2025; Patel-Lippmann et al., RadioGraphics 2023.1415
With placenta previa and three prior cesarean deliveries, the risk of PAS is 40% — nearly 1 in 2. After five prior C-sections with previa, the risk reaches 67%. These numbers underscore why screening is essential for any patient with a history of cesarean delivery.
IVF and PAS Risk
IVF (in-vitro fertilization) pregnancies have been linked to higher rates of PAS. However, a 2025 comprehensive review clarifies that this association is probably indirect rather than a direct effect of IVF itself. The increased risk is likely explained by the strong association between IVF and placenta previa, and also indirectly through maternal age and prior uterine surgery — both of which are more common in IVF patients.14
If you conceived through IVF, your risk of PAS is elevated primarily because of the higher likelihood of placenta previa and because IVF patients tend to be older and more likely to have had prior uterine procedures. IVF itself does not appear to directly cause abnormal placental invasion. Standard screening recommendations apply: if you have placenta previa and any prior C-section, discuss PAS screening with your provider.
Risks to the Mother
Maternal risk varies dramatically depending on which treatment path is chosen. Below, we break down the evidence for each of the three main approaches: cesarean hysterectomy, conservative management (leave in situ), and fertility-preserving surgery (one-step/Triple-P).
Cesarean Hysterectomy
Cesarean hysterectomy — delivering the baby via cesarean section and then removing the uterus with the placenta still attached — has been the standard treatment for PAS for decades. It eliminates the source of the problem entirely but at a significant cost.
| Complication | Rate / Range | Notes |
|---|---|---|
| Severe hemorrhage | ~59% experience >3L blood loss | EBL 2,000–8,000 mL; mean ~3,000 mL[3] |
| Blood transfusion | ~50–82% | Massive transfusion protocol often activated[4] |
| ICU admission | Common | Especially with percreta; 24–68% reported[3] |
| Bladder injury | ~20% | Higher with anterior percreta[5] |
| Ureteral injury | 5–7% | Often requires stent placement[5] |
| Intraoperative urologic complications | 10–15% | In patients with multiple prior C-sections and previa accreta[14] |
| Bowel injury | Possible | Primarily with percreta invading bowel[5] |
| Infection | Lower than conservative | Infected tissue is removed entirely |
| Mortality | 0.05–0.25% | At expert centers; higher elsewhere[1] |
| Fertility preserved | 0% | Uterus is removed — permanent, irreversible |
| Emotional/psychological | Significant | Grief over fertility loss, PTSD possible[6] |
Conservative Management (Leave Placenta In Situ)
In conservative management, the baby is delivered but the placenta is left in place, either entirely or partially. The cord is cut, the uterus is closed, and the body is allowed to resorb the placental tissue over weeks to months. This avoids the immediate trauma of hysterectomy but introduces different risks over a longer time period.
| Complication | Rate / Range | Notes |
|---|---|---|
| Severe hemorrhage | ~16.3% severe PPH | Significantly LOWER than hysterectomy[7] |
| Blood transfusion | Lower rates | Compared to hysterectomy[7] |
| ICU admission | Lower | Immediate surgical morbidity reduced |
| Organ injury | Lower | No dissection of invaded tissues[7] |
| Infection / endometritis | HIGHER than hysterectomy | Retained tissue is a nidus for infection[7] |
| Readmission | HIGHER | Within 6 months; bleeding or infection[7] |
| Delayed hemorrhage | Risk persists weeks–months | During placental resorption period |
| Delayed hysterectomy | 22–33% | Eventually need hysterectomy anyway[7][8] |
| Sepsis | Rare | Potentially fatal; requires vigilant monitoring |
| Intrauterine adhesions | Reported in multiple patients | 8 women in Sentilhes series developed amenorrhea[8] |
| Mortality | Lower (data limited) | Avoids major surgical risk[7] |
Fertility-Preserving Surgery (One-Step / Triple-P)
In fertility-preserving surgery, the surgeon removes the abnormally attached placenta along with the invaded portion of the uterine wall, then repairs the uterus. This aims to combine the benefits of both approaches: removing the pathology (like hysterectomy) while preserving the uterus (like conservative management).
| Complication | Rate / Range | Notes |
|---|---|---|
| Hemorrhage | Mean EBL 500–1,300 mL | Lower than both alternatives[9] |
| Blood transfusion | 67.2% | vs 81.8% for hysterectomy[9] |
| Conversion to hysterectomy | 10–20% | If bleeding cannot be controlled[9] |
| Organ injury | Possible but lower | Compared to hysterectomy |
| Operative time | 164.4 min | vs 216.5 min for hysterectomy[9] |
| Mortality | Data limited | Likely comparable to conservative management |
| Fertility preserved | 80–90% | When conversion to hysterectomy is not needed |
Comparing All Three Approaches
The chart below compares the three treatment approaches across five key metrics. Note that each approach has trade-offs — there is no option that is best in every category.
For most metrics, lower is better (less blood loss, fewer transfusions, less ICU time, less infection). The exception is Fertility Preserved, where higher is better. No single approach wins across all categories — the right choice depends on individual circumstances.
Risks to the Baby
The primary risk to babies in PAS pregnancies is prematurity. Because delivery is typically planned at 34–36 weeks to reduce the risk of maternal hemorrhage from spontaneous labor, nearly all PAS babies are born early. The good news: with modern neonatal care, most of these babies do well.
PAS Babies vs. Normal Pregnancies
| Risk | PAS Pregnancies | Normal Pregnancies |
|---|---|---|
| Preterm birth (<37 wks) | ~76% | ~10% |
| NICU admission | 29.8% | 18.2% |
| Low APGAR (<7 at 5 min) | 8.3% | 1.0% |
| Mechanical ventilation | 9.8% | 3.8% |
| Mean birthweight | 2,625–2,660g | ~3,400g |
Sources: Erfani et al. 2019[10]; Balayla & Bhondoekhan et al. 2019[11]
Why These Risks Exist
- Early delivery: Baby is typically delivered at 34–36 weeks to reduce the risk of maternal hemorrhage from spontaneous labor
- Prematurity is the primary source of neonatal risk — not the placental disorder itself
- Antenatal corticosteroids (betamethasone) are given before delivery to accelerate lung maturity, reducing but not eliminating respiratory complications
- NICU stay is common but most babies do well with supportive care and are discharged within days to weeks
Planned vs. Emergency Delivery
One of the most striking findings in PAS research is how much better outcomes are when delivery is planned rather than emergent. Emergency delivery — often triggered by uncontrolled bleeding or premature labor — dramatically worsens neonatal outcomes. Approximately 35% of patients with placenta previa accreta require unplanned emergency delivery, underscoring the importance of early diagnosis and proactive planning.14
| Outcome | Planned Delivery | Emergency Delivery | Odds Ratio |
|---|---|---|---|
| Lower birthweight | Baseline | Higher risk | 3.8 |
| Low APGAR | Baseline | Higher risk | 5.2 |
| NICU admission | Lower | Higher | 3.6 |
| NICU stay ≥7 days | Lower | Higher | 2.3 |
Source: Erfani et al. 2019[10]
With planned delivery at an experienced center, most babies do well despite being born early. The biggest risk to babies is UNPLANNED delivery. This is one of the strongest arguments for early diagnosis, specialist referral, and delivering at a center of excellence.
Risks to Future Children & Fertility
For patients who desire more children, the choice of treatment approach has profound implications for future fertility. This is often the most emotionally difficult part of the decision-making process.
After Cesarean Hysterectomy
- No future pregnancies possible — the uterus is removed
- This is permanent and irreversible
- Surrogacy or adoption remain options for growing a family
- Ovaries are typically preserved, so hormonal function is maintained
After Conservative Management (Leave In Situ)
- 88.9% of women desiring pregnancy achieved it[8]
- Mean time to conception: 17.3 months
- BUT: PAS recurs in 28.6% of subsequent pregnancies[8]
- Postpartum hemorrhage in 10–19% of subsequent pregnancies
- Risk of uterine rupture: 1.3%
- Intrauterine adhesions can impair fertility in some cases (8 women in the Sentilhes series developed amenorrhea)[8]
Across all uterine-preserving approaches (both leave-in-situ and surgical conservation), the overall recurrence risk of PAS exceeds 20% in subsequent pregnancies.14 This is a critical consideration: patients who retain their uterus must be closely monitored in any future pregnancy, with early specialist imaging to check for recurrent PAS.
A 2021 worldwide survey of 134 centers found that only 10% routinely offer uterine-sparing management as an option for PAS.14 If preserving your uterus is important to you, you may need to actively seek out a center with experience in conservative or fertility-preserving approaches. Ask your provider directly whether uterine conservation is offered at their institution.
After One-Step Conservative Surgery
- 202 subsequent pregnancies documented in the literature[9]
- 90% delivered at term (>37 weeks)
- 0% PAS recurrence — because the abnormal tissue was removed
- Outcomes similar to normal pregnancies
- Average wait before attempting pregnancy: 15–18 months
Comparison of Future Fertility Outcomes
| Outcome | Hysterectomy | Leave In Situ | Conservative Surgery |
|---|---|---|---|
| Future pregnancy possible | No | Yes (67–78%) | Yes (80–85%) |
| If pregnant, term delivery | N/A | ~62% (21/34) | 90% |
| PAS recurrence | N/A | 28.6% | 0% (one-step); >20% overall when uterus preserved[14] |
| PPH risk in next pregnancy | N/A | 10–19% | Low |
| Uterine rupture risk | N/A | 1.3% | Low |
The Risk of NOT Being Diagnosed
Perhaps the single most dangerous scenario in PAS is arriving at delivery without a prenatal diagnosis. When PAS is not suspected, the obstetrician may attempt to manually remove the placenta — which can trigger catastrophic, life-threatening hemorrhage.
| Metric | Diagnosed Before Delivery | Undiagnosed at Delivery |
|---|---|---|
| Estimated blood loss | ~2,750 mL | ~6,100 mL |
| Transfusion needed | 59% | 94% |
| Maternal mortality | <1% (expert centers) | Up to 30% |
Sources: FIGO 2018[2]; Shamshirsaz et al. 2015[12]
FIGO estimates that 50–67% of PAS cases are undiagnosed before delivery in general practice settings. The vast majority of PAS-related deaths occur in undiagnosed cases. Screening at 18–20 weeks with a targeted ultrasound — especially in women with prior cesarean deliveries — could prevent most of these deaths.[2]
The Risk of WHERE You Deliver
Not all hospitals are equipped to manage PAS. The evidence is unambiguous: outcomes are dramatically better at high-volume, specialized centers with an experienced multidisciplinary team.
What Makes an Expert Center?
- High case volume — surgical skill correlates directly with the number of PAS cases managed
- Multidisciplinary team (MDT) — maternal-fetal medicine, experienced PAS surgeon, anesthesiology, interventional radiology, urology, neonatology, blood bank, ICU
- Massive transfusion protocol — blood products immediately available
- Level III or IV NICU — for the preterm baby
- Institutional protocols — standardized PAS care pathways
If you have been diagnosed with PAS, ask your provider: "How many PAS cases does this hospital manage per year? Is there a dedicated multidisciplinary PAS team?" If the answer is fewer than 5–10 cases per year, strongly consider transferring care to a center of excellence, even if it means traveling.[1]
Emotional & Psychological Risks
The risks of PAS are not only physical. A PAS diagnosis — and the treatment that follows — can have a profound impact on mental and emotional health for patients, partners, and families.
Common Psychological Impacts
- Anxiety and distress from the moment of diagnosis through delivery and recovery
- Post-traumatic stress disorder (PTSD) — especially after traumatic surgical experiences or emergency deliveries
- Grief over fertility loss — for those who undergo hysterectomy, the loss of the ability to carry future children can be devastating[6]
- Complicated bonding — separation from the baby due to NICU stay or maternal ICU admission
- Partner and family impact — witnessing a life-threatening surgical event is traumatic for partners and family members as well
Seek support from:
- National Accreta Foundation (preventaccreta.org) — peer support, resources, and community
- Social workers at your hospital — many PAS centers have dedicated social workers
- Mental health professionals who specialize in perinatal trauma
- Online communities of PAS survivors who understand what you are going through
Asking for help is not a sign of weakness — it is one of the most important things you can do for yourself and your family.
Risk Reduction Strategies
While PAS cannot be prevented once it has developed, nearly every risk described on this page can be significantly reduced through proactive steps. Here is what the evidence supports:
Key Interventions
- Early screening: Women with prior cesarean deliveries and placenta previa should receive targeted ultrasound at 18–20 weeks
- Specialist referral: Once PAS is suspected, referral to a maternal-fetal medicine specialist and an experienced PAS surgeon
- Deliver at an experienced center: A center with a dedicated MDT and high PAS case volume
- Planned delivery: Scheduled at 34–36 weeks, reduces emergency risks to both mother and baby
- Blood products available: Massive transfusion protocol activated before surgery begins
- Antenatal corticosteroids: Given 24–48 hours before delivery to accelerate the baby's lung maturity
- Psychological preparation: Mental health support before and after delivery
Prevention: Reducing Unnecessary C-Sections
Because prior cesarean delivery is the most significant risk factor for PAS, reducing the rate of unnecessary cesarean sections is the most efficient preventive measure at the population level.14
Each cesarean delivery creates a uterine scar. In subsequent pregnancies, the placenta may implant into that scar tissue, which is the fundamental mechanism behind PAS. As global C-section rates continue to rise, PAS incidence is expected to increase in parallel. Advocating for vaginal birth when medically appropriate — especially for a first delivery — is a key public-health strategy for preventing PAS.
Emerging Risk Factors: Endometriosis & Adenomyosis
Recent research has identified endometriosis and adenomyosis as independent risk factors for PAS, with approximately 3-fold increased odds (adjusted OR 3.39 for endometriosis; OR 2.3–3.1 for adenomyosis).16 The risk appears to increase with endometriosis severity — stage IV endometriosis was found in 64% of PAS cases versus 34% of controls. These conditions share key biological mechanisms with PAS, including decidualization defects and disruption of the endometrial-myometrial interface. See the Understanding PAS page for a detailed discussion of the evidence, shared pathophysiology, and the IVF confounding factor.
Key Takeaways
Expert centers with multidisciplinary teams report near-zero mortality. Community hospitals without PAS experience report dramatically worse outcomes. If you have PAS, the hospital you choose may be the most important decision you make.
For both mother and baby, scheduled delivery at 34–36 weeks with a prepared team yields far better results than emergency surgery. This is why early diagnosis is so critical.
For patients who desire future pregnancies, both conservative management and fertility-preserving surgery offer paths to preserve the uterus. Each has trade-offs, but the data shows that future pregnancies are possible and often successful.
While prematurity carries risks, modern neonatal care means that the vast majority of PAS babies thrive. The biggest risk to babies is unplanned delivery, not the scheduled early delivery itself.
PAS affects the whole person — not just the body. Seek support from the National Accreta Foundation, mental health professionals, and communities of PAS survivors. You do not have to face this alone.
References
- Silver RM, Fox KA, Barton JR, et al. Center of excellence for placenta accreta. Am J Obstet Gynecol. 2015;212(5):561–568. doi:10.1016/j.ajog.2014.11.018
- Jauniaux E, Chantraine F, Silver RM, Langhoff-Roos J; FIGO Placenta Accreta Diagnosis and Management Expert Consensus Panel. FIGO consensus guidelines on placenta accreta spectrum disorders. Int J Gynaecol Obstet. 2018;140(3):265–273. doi:10.1002/ijgo.12408
- Shamshirsaz AA, Fox KA, Salmanian B, et al. Maternal morbidity in patients with morbidly adherent placenta treated with and without a standardized multidisciplinary approach. Am J Obstet Gynecol. 2015;212(2):218.e1–218.e9. doi:10.1016/j.ajog.2014.08.019
- Eller AG, Bennett MA, Sharshiner M, et al. Maternal morbidity in cases of placenta accreta managed by a multidisciplinary care team compared with standard obstetric care. Obstet Gynecol. 2011;117(2 Pt 1):331–337. doi:10.1097/AOG.0b013e3182051db2
- Bowman ZS, Eller AG, Bardsley TR, et al. Risk factors for placenta accreta: a large prospective cohort. Am J Perinatol. 2014;31(9):799–804. doi:10.1055/s-0033-1361833
- Tol ID, Yousif M, Collins SL. Post-traumatic stress disorder and the role of patient support in placenta accreta spectrum. Eur J Obstet Gynecol Reprod Biol. 2020;251:260–264. doi:10.1016/j.ejogrb.2020.05.065
- Sentilhes L, Ambroselli C, Kayem G, et al. Maternal outcome after conservative treatment of placenta accreta. Obstet Gynecol. 2010;115(3):526–534. doi:10.1097/AOG.0b013e3181d066d4
- Sentilhes L, Kayem G, Ambroselli C, et al. Fertility and pregnancy outcomes following conservative treatment for placenta accreta. Hum Reprod. 2010;25(11):2803–2810. doi:10.1093/humrep/deq239
- Pinas-Carrillo A, Chandraharan E. Placenta accreta spectrum: risk factors, diagnosis, management and outcomes with a focus on the Triple P procedure. BMC Pregnancy Childbirth. 2019;19:417. doi:10.1186/s12884-019-2547-2
- Erfani H, Fox KA, Clark SL, et al. Maternal outcomes in unexpected placenta accreta spectrum disorders: single-center experience with a multidisciplinary team. Am J Obstet Gynecol. 2019;221(4):337.e1–337.e5. doi:10.1016/j.ajog.2019.05.035
- Balayla J, Bondarenko HD. Placenta accreta and the risk of adverse maternal and neonatal outcomes. J Perinat Med. 2013;41(2):141–149. doi:10.1515/jpm-2012-0219
- Shamshirsaz AA, Fox KA, Erfani H, et al. Outcomes of identified compared with unidentified placenta accreta spectrum at a tertiary referral center. Obstet Gynecol. 2018;132(6):1465–1473. doi:10.1097/AOG.0000000000002980
- Knight M; UKOSS. Peripartum hysterectomy in the UK: management and outcomes of the associated haemorrhage. BJOG. 2007;114(11):1380–1387. doi:10.1111/j.1471-0528.2007.01507.x
- Jauniaux E, Silver RM, Bhide A, et al. Placenta accreta spectrum. Nat Rev Dis Primers. 2025;11:17. doi:10.1038/s41572-025-00624-3
- Patel-Lippmann K, Engeler CE, Engel H, et al. Placenta accreta spectrum disorder: SAR-ESUR joint consensus statement. RadioGraphics. 2023;43(6):e220090. doi:10.1148/rg.220090
- Uccella S, Manzoni E, Cromi A, et al. Endometriosis and placenta accreta spectrum: a systematic review and meta-analysis. Biomedicines. 2022;10(3):616. PMC8962380 | doi:10.3390/biomedicines10030616