SMFM issues guidelines for managing patients with third trimester bleeding between 34 0/7-36 6/7 weeks.

Third trimester bleeding is not so uncommon and nearly 1 in 10 women will experience vaginal bleeding during this period. It may present as just spotting or may be heavier. It could be just due to softening and opening of cervix or a sign of more serious obstetric nightmare like placenta previa or abruption.

Optimal management of third trimester bleeding depends on accurate identification of the cause and the gestational age window.

The earlier Society for Maternal-Fetal Medicine (SMFM) recommendations were not specific to the gestational age. The recommendations were published electronically in October in American Journal of Obstetrics and Gynecology.

Recommendations: 

If a patient with placenta previa is stable and have no other obstetric complications, deliver her at 36–37 6/7 weeks of gestation. If this episode is mild and self-limiting, but there is history of previous bleeding episodes < 34 weeks, deliver her to avoid risk of major bleeding episode in future. (Grade 1B)

Routine cervical length screening for women with placenta previa is not indicated in the late preterm period because of a lack of data on an appropriate management strategy (Grade 2C)

A stable woman with placenta accreta, schedule a planned delivery between 34 and 37 weeks of gestation.  (Grade 1C)

A stable woman with vasa previa, schedule a planned delivery between 34 and 37 weeks of gestation.  (Grade 1C)

Recommendations are less clear about ideal time of delivery in placental abruption for women who are hemodynamically stable along with the fetus. Delivery may be prolonged with close monitoring of mother and fetus. If the women with abruptio is hemorrhaging profusely, she should undergo delivery.

If a woman is bleeding profusely, do not defer delivering her for the purpose of administering corticosteroids.  (Grade 1B)

Fetal lung maturity testing is not indicated in late preterm period, when a indication for delivery is already present.  (Grade 1B)

Administer antenatal corticosteroids to women who are eligible, stable and are being managed expectantly and delivery is expected within 7 days, the gestational age is between 34 and 36 6/7 weeks of gestation, and antenatal corticosteroids has not previously been given (Grade 1A).

Clinical Considerations:

For placenta previa, vasa previa or accreta, cesarean section should be performed. For other clinical situation, in absence of contraindications to vaginal delivery and fetus in stable condition, a vaginal delivery might be attempted.

Very small amount of vaginal bleeding, that resolves by the time the patient presents in the hospital, can be managed expectantly provided the patient and fetus are stable and patient has access to emergency care 24/7.

Perform an ultrasound for evaluation of cause of bleeding and location of placenta before doing a digital examination. For suspected placenta previa vaginal ultrasound is a better choice and pulsed-wave doppler may help identify a fetal arterial vessel (with FH rate) or fetal vessels with venous flow in vasa previa.

In cases of placenta accreta, ultrasound can be performed but the sensitivity and specificity is less than for placenta previa and vasa previa.

In cases of placental abruption, always rely on clinical acumen as sonography can miss the diagnosis in 20-50% of cases.

MRI is contraindicated in women with active bleeding in third trimester.

Abstract

ACOG updates guidance on postpartum hemorrhage- calls for standard, coordinated, protocol based intervention

The American College of Obstetricians and Gynecologists (ACOG) recently released expanded guidelines for management of postpartum hemorrhage (PPH)—the leading cause of maternal mortality worldwide.

PPH is defined as total blood loss of 1000 ml or more along with signs or symptoms of hypovolemia within 24 hours after the labor, but can occur up to 12 weeks postpartum. Although Maternal Mortality Rates(MMR) have decreased worldwide in last 4 decades, it still accounts for 10% of all pregnancy related mortality.

Incidence varies, but 1-5% is reasonable estimate, with uterine atony accounting for 70-80% of cases PPH.

This practice bulletin discusses the risk factors along with evaluation, prevention, and management of maternal hemorrhage.

It also calls upon all obstetricians and other obstetric care providers to formulate standard protocols for recognizing, evaluating and management of maternal hemorrhage by multidisciplinary approach and implement it in every center.

Multidisciplinary teams, including physicians, nurses and midwives, should be trained to implement key elements in four categories, including readiness to respond; recognition and prevention measures; multidisciplinary response; and data reporting and systematic learning, including drills like simulation-based training.

ACOG also has partnered with multiple organization to implement the care bundle suggested by  Alliance for Innovation on Maternal Health (AIM), which many states have are already adapted.

It also lays emphasis on identifying the patients at risk of developing PPH, prenatally, during admission and during labor. It includes patients with vaginal lacerations, retained placenta, abnormally adherent placenta with previous cesarean section. All Ob-gyn should be aware of high risk of PPH in placenta previa with previous uterine scar.

Uterotonic agents should be the first line of treatment in case of atonic PPH, choice of a specific agent is at the discretion of the provider as none is identified as superior over other. Active management of third stage of labor should be implemented.

All hospitals, especially those in rural areas should be able to escalate the efforts quickly, and have a specific plan to go to next level of treatment or quickly refer patient to a specialty hospital.

Tranexamic acid can be given when primary line of therapy fails, it is especially found effective if given within 3 hours of birth.

Surgical approach includes Intrauterine balloon tamponade, but less invasive methods should always be used first. 

All hospitals should have functioning massive transfusion protocols and ‘hemorrhage carts’, with all the necessary medication in place.

The Practice Bulletin #183, "Postpartum Hemorrhage" is published in October issue of Obstetrics and Gynecology.

ACOG press release

Patient Safety Bundles on obstetric hemorrhage. 

Ultrasound is sufficient for prenatal diagnosis of placenta previa accreta: a systematic review and meta-analysis

Ultrasound is highly sensitive and specific in diagnosing placenta previa accreta, after previous cesarean section when performed by skilled sonologist reports the results of a systematic review and meta-analysis by Jauniaux and Bhide published in July issue of Obstetrics and Gynecology.

Placenta accreta is a potential life-threatening condition and requires multidiscipline involvement for successful management and reducing maternal and neonatal morbidity and mortality. Because of increasing incidence of cesarean sections, the incidence of morbidly adherent placenta is on rise.

The incidence of placenta previa accreta was 4.1% in women with 1 prior cesarean and 13.3% in women with ≥2 previous cesarean deliveries.

Prenatal diagnosis of placenta accreta allows for sufficient time and planning by involving the concerned discipline to be prepared in advance.

The researchers included data from 14 cohort studies with 3889 pregnancies presenting with placenta previa or low-lying placenta and 1 or more prior cesarean deliveries in the quantitative analysis.

There were 328 (8.4%) cases of placenta previa accreta, 90% (298 cases) of which were diagnosed with ultrasound.

Two hundred and eight patients underwent cesarean hysterectomy out of 232 cases (89.7%)

The odds of diagnosing placenta accreta were higher in prospective studies (odds ratios = 228.5) as compared to retrospective studies (odds ratio=80.8). Sonography was more accurate in diagnosing placenta accreta as the depth of villous invasion increased.

The authors stressed the need of developing screening protocols for better management of this increasingly common and life threatening obstetric complication.

Placental Accreta Index (PAI) was recently proposed to predict individual risk for morbidly adherent placenta using 2-D and color Doppler sonographic exam. It includes 5 parameters: 2 or > cesarean delivery, lacunae, myometrial thickness, anterior placenta previa and bridging vessels.

Each parameter was weighted to create a 9-point scale in which a score of 0-9 provided a probability of invasion that ranged from 2–96%, respectively. The probability of invasion increases with increasing PAI score, such that a score of 9 confers a 96% chance of histologic placental invasion.

But, the score needs further validation before it can be used as a standardized method in prediction of placenta accreta, but it definitely improved the  antenatal detection.

Abnormally invasive placenta---Can we predict and do better?

Clinical Pearls:

• Previous cesarean section or uterine surgery is the single most important predisposing factors for Abnormally Invasive placenta.
• One cesarean section increases the risk of AIP seven fold in subsequent pregnancy.
• History of post-partum hemorrhage is also a risk factor for AIP and increases the risk 6 fold in current pregnancy.
• In 70% of cases, the diagnosis of AIP was missed during antenatal period.
• Increasing clinician awareness for incidence of AIP in the high risk patients leads to increased diagnosis in antenatal period.
• Avoiding unnecessary cesarean section is the only way to decrease the incidence of AIP.  

Lowering the Cesarean section rate in the population is the only most effective way in reducing the incidence of Abnormally invasive placenta(AIP) is the conclusion of a large, population based cohort study from the Nordic countries.

The Nordic Obstetric Surveillance Study (NOSS) required obstetricians’ collaboration in reporting AIP, uterine rupture, excessive blood loss and peripartum hysterectomy from 2009-2012. Due to paucity of cases at a single hospital the data was pooled and validated by National Health Registries. 

The data was analyzed and identified 205 cases of AIP amounting to an incidence of 3.4 per 10,000 deliveries.

The study was published in the current issue of British Journal of Obstetrics and Gynecology(BJOG).[1]

The study goal was to gauge the prevalence, risk prediction, predisposing factors, antenatal suspicion, maternal morbidity and birth complications in cases of AIP.

The study confirmed the association between AIP and previous cesarean section or any other previous uterine surgeries like endometrial ablation, and in vitro fertilization. The risk of AIP in subsequent pregnancy is seven fold with one prior Cesarean section to 56-fold after three or more CS.

Placenta previa was the single most important risk factor identified in nearly half of the pregnancies.

 In addition, patient who had postpartum hemorrhage in previous pregnancy have 6 times the risk of AIP in current pregnancy as compared to patients who did not have PPH.

An antenatal diagnosis of AIP can strikingly reduce the complication rate but in nearly two-third of patients (70%) of patients the diagnosis was missed. Of these, 39% had prior CS and 33% had placenta praevia.

Increased awareness about the risk factors among clinicians can raise the index of suspicion and led to more and more patients being diagnosed in prenatal period. Clinicians performing Ultrasound(USG) should have high index of suspicion in high risk women with previous uterine surgery or a placenta over uterine scar. These women should be offered additional sonography.

Nordic countries have lower rates of AIP than US, perhaps due to lower rate of cesarean section and high order cesarean births or better obstetrics facilities. 

But, the only sure way to decrease the incidence of AIP is to avoid unnecessary cesarean delivery, especially the first cesarean section.

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[1] Thurn L, Lindqvist PG, Jakobsson M, Colmorn LB, Klungsoyr K, Bjarnadóttir RI, Tapper AM, Børdahl PE, Gottvall K, Petersen KB, Krebs L, Gissler M, Langhoff-Roos J, Källen K. Abnormally invasive placenta—prevalence, risk factors and antenatal suspicion: results from a large population-based pregnancy cohort study in the Nordic countries. BJOG 2015; DOI: 10.1111/1471-0528.13547.