Grand Rounds

Does Prenatal Diagnosis of Placenta Accreta Help Reduce Adverse Perinatal Outcomes?

BACKGROUND AND PURPOSE:

Abnormally invasive placenta is increasing due to increased cesarean section rates
- Placenta accreta: Chorionic villi adherent to the myometrium
- Placenta increta: Chorionic villi invade myometrium
- Placenta percreta: Chorionic villi invade through the myometrium, serosa and possibly surrounding organs and structures
Buca et al. (Ultrasound in Obstetrics & Gynecology, 2018) sought to determine the impact of prenatal diagnosis for abnormally invasive placenta on outcomes

Systematic review and meta-analysis
- Database search of studies measuring impact of prenatal diagnosis on surgical outcome for abnormally invasive placenta cases
- Compared prenatal to intrapartum abnormally invasive placenta diagnosis
- Prenatal diagnosis based on ultrasound, with MRI as needed
Outcomes
- Gestational age at birth | Amount of blood loss (L) | Units of RBCs, platelets and FFP transfused | Length of stay in hospital and ICU | Urinary tract injury and infection

Thirteen studies were included
Hysterectomy rate was not significantly different between groups
- Prenatal abnormally invasive placenta diagnosis: 83.7%
- Intrapartum abnormally invasive placenta diagnosis: 75.1% (P = 0.07).
Interventional radiology was performed more often when abnormally invasive placenta was diagnosed prenatally
- Prenatal abnormally invasive placenta diagnosis: 53.5%
- Intrapartum abnormally invasive placenta diagnosis: 16.0%
Compared to those with an intrapartum diagnosis, women with a prenatal diagnosis of abnormally invasive placenta
- Lost less blood loss during surgery
  - Mean difference (MD) −0.87; 95% CI, −1.5 to −0.23 (P=0.008)
- Required fewer transfused units of
  - RBCs: MD −1.45; 95% CI, −2.9 to −0.04 (P=0.04)
  - FFP: MD −1.73; 95% CI, −3.3 to −0.2 (P=0.03)
- Delivered earlier
  - MD -1.33 weeks; 95% CI, −2.23 to −0.43 (0.004)
There was no difference in risk of admission to an ICU, length of hospital stay or ICU stay
Prenatal diagnosis of abnormally invasive placenta was associated with a higher risk of urinary‐tract injury (odds ratio, 2.5; 95% CI, 1.3–4.6), due to the higher prevalence of placenta percreta in this group
- Could include planned surgical approach, not necessarily unintentional error

Authors recognize study limitations including small number of included studies, some with less rigorous design (e.g. retrospective, non-randomized)
- Limited data could result in the study being underpowered for less common outcomes
Percreta over-represented in the prenatal diagnosis group, leading to potential bias
Prenatal diagnosis of abnormally invasive placenta leads to fewer complications during and following delivery
- Allows for delivery at expert centers
- Larger studies required to determine best management approach

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