June 21, 2022
Though laypeople in the U.S. may think of maternal death as something occurring in another century or on other continents, those practicing in the nation's field of obstetrics know that it's not. In fact, approximately 700 women nationwide die yearly from complications due to pregnancy, childbirth or post-delivery, according to the Centers for Disease Control and Prevention (CDC). The No. 1 direct cause of maternal mortality globally is postpartum hemorrhage (PPH), according to a 2014 publication in the Lancet Global Health. Additionally, PPH necessitating blood transfusion is the No. 1 cause of maternal morbidity, reports Dr. Creanga and colleagues in a 2014 issue of Journal of Women's Health.
"One of the biggest things obstetricians are concerned about is hemorrhage," says Vanessa E. Torbenson, M.D, an obstetrician-gynecologist at Mayo Clinic's campus in Minnesota.
Consistent with recent efforts by the CDC and the American College of Obstetricians and Gynecologists (ACOG), Mayo Clinic Obstetrics and Gynecology strives to play a role in decreasing maternal morbidity and mortality by continuously improving PPH monitoring, prevention and treatment.
The majority of PPH — about 98% — occurs immediately post-delivery, though some patients present with delayed PPH, according to Dr. Torbenson.
PPH measurement evolution
For years, U.S. obstetricians used a qualitative, estimate-based approach to blood loss measurement, says Dr. Torbenson.
"The provider would note, 'That looks like about 300 cc of blood, or around 500 cc of blood,' " she says.
However, the obstetrics community realized the insufficiency of approximations over time, with physicians estimating blood loss differently. This led the field to transition to a quantitative blood loss measure.
In 2017, ACOG redefined PPH as 1,000 cc of blood loss. The previous definition for vaginal delivery was more than 500 cc of blood loss or cesarean section with more than 1,000 cc lost. At 1,000 cc, Dr. Torbenson indicates that hypovolemia symptoms become significant.
Today, Mayo Clinic most often uses waterproof collection drapes for patients delivering vaginally or by cesarean section. The drapes collect all fluids into a measurement bag. Health care providers read the measurement of fluid in the bag prior to delivery and subtract from the measurement after delivery to give a measurement of total blood in the drapes. Obstetric staff add this sum to blood measured in canisters and weighed sponges used to soak up blood to arrive at a total measurement.
Dr. Torbenson says device companies are developing technology to measure PPH with photometrics, calculating and measuring blood loss through a visual reading.
For many years, Mayo Clinic used its own PPH algorithm, which had the doses and names of important medications needed. Now it uses ACOG's stage-based approach, classifying PPH into stages 1 to 4, reflecting blood loss volume and whether the loss is ongoing. This system also aligns with the Alliance for Innovation on Maternal Health's principles. Mayo Clinic changed its protocol based on the published outcomes of improvement in maternal morbidity from a more staged-based approach.
"A patient could have 999 cc of blood loss and continued bleeding, or bleeding may be under control," says Dr. Torbenson.
The quantitative algorithm with recommended actions for each stage assists decision-making in a potentially stressful environment surrounding delivery with complications.
"The stage-based system helps the practitioner, removing guesswork," she says. "When a lot is going on, it can be hard to determine the best next step. This system lays it out."
PPH risk factors and treatment
Several factors lead to PPH susceptibility, says Dr. Torbenson:
- Atony. The No. 1 risk factor for PPH is atony — or atypical uterine contraction post-placental delivery.
- Overdistension of uterine muscle. This factor occurs most commonly after twin or large-infant delivery.
- Oxytocin. This induction medication can cause uterine muscle to become less sensitive and hinder uterine contraction post-delivery.
- Retained placenta. Placentas that do not completely emerge post-delivery can prompt hemorrhage.
- Lacerations from delivery. Lacerations occur at times with vaginal delivery, especially with vacuum or forceps use, requiring suture. Surgical lacerations may also occur during cesarean sections.
- Abnormal placentation. Multiple cesarean sections accompanied by placental implantation abnormalities may provoke hemorrhage. With rising cesarean section rates, providers may diagnose this condition pre-delivery with the help of targeted ultrasound and MRI and then prepare a multidisciplinary team for a surgery that can avoid catastrophic bleeding. This often requires a hysterectomy. However, if the placental invasion is not too deep, the provider can preserve the uterus.
- Cesarean section. Increased blood loss is more common at cesarean deliveries due to their surgical nature, especially cesareans that occur after a long labor.
The obstetrician's role is to determine factors prompting PPH. However, if these factors are unknown, Dr. Torbenson recommends addressing atony, as this is the most common cause, and continuing to look for other causes if not improved.
Mayo Clinic practitioners treat atony with IV fluids and uterotonics such as misoprostol, carboprost and oxytocin, which has proved effective as a solo first line treatment, according to a 2020 Cochrane Database of Systematic Reviews publication. In addition, since a randomized controlled trial showed that tranexamic acid improved morbidity and mortality for patients with hemorrhage, it also has become a first line treatment.
Mayo Clinic also uses an FDA-approved vacuum-induced hemorrhage control system, a device with a loop that injects sterile liquid and then provides suction while inserted into the uterus for an hour. A 2020 Obstetrics and Gynecology publication on study results for this device reported hemorrhage control three minutes post-device placement. Mayo Clinic obstetrics practitioners also use an intrauterine balloon catheter filled with fluid that applies uterine wall pressure. Dr. Torbenson also suggests transfusing based on vital signs, even preemptively, if concerning.
"If you wait for the blood count to confirm, it can be too late for the patient," she says.
As a last resort to prevent maternal mortality, she recommends hysterectomy.
Potential symptoms to watch that may indicate PPH include:
- Elevated heart rate
- Decreased blood pressure
- Coloring turning gray or pale
- Ringing in the ears
It is also crucial for obstetricians to be attentive when patients voice feeling unwell post-childbirth in the delivery room or postpartum unit. Dr. Torbenson also suggests ensuring that patients know how to contact a nurse if they have concerns pre- or post-dismissal.
PPH prevention and risk assessment
As PPH is an emergency and can be lethal, Dr. Torbenson advocates for prevention, suggesting the following steps:
- Prescribing prenatal vitamins and iron, especially if the patient's blood count is low
- Advising on weight gain and the need to disclose supplements used
- Training all midwives and obstetricians in hemorrhage care
When pregnant patients arrive for delivery, Dr. Torbenson and colleagues at Mayo Clinic estimate the risk of hemorrhage. They have at the ready a hemorrhage kit, a type and screen for patients at elevated risk of bleeding, and anesthesiologists and interventional radiologists who can perform a postpartum hemorrhage embolization.
Referral for patients at risk
While pregnant patients in high-risk situations occasionally arrive at Mayo Clinic on an emergent basis by helicopter or fixed-wing aircraft, Dr. Torbenson encourages practitioners to refer patients with high-risk pregnancies — such as patients with an abnormal placentation, rare antibody screens or history of significant hemorrhage, or patients who hope to have a vaginal birth after cesarean — to an obstetric center that routinely handles this level of care. High-risk care, such as at Mayo Clinic, occurs under the expertise of highly skilled obstetric providers, maternal-fetal medicine specialists, and a multidisciplinary team. They use up-to-date PPH intervention tools and simulate emergencies such as PPH for routine preparation in managing these conditions. The Mayo Clinic practice routinely reviews its protocols and updates based on new data or technology that becomes available.
Dr. Torbenson suggests pre-delivery as the ideal referral time frame. However, she indicates that practitioners may also call Mayo Clinic Obstetrics and Gynecology when a patient is in labor for a discussion about whether the patient should deliver locally or transfer to another facility.
For more information
Preventing pregnancy-related deaths. Reproductive Health. Centers for Disease Control and Prevention.
Say L, et al. Global causes of maternal death: A WHO systematic analysis. Lancet Global Health. 2014; 2:e323.
Creanga AA, et al. Maternal mortality and morbidity in the United States: where are we now? Journal of Women's Health. 2014; 23:3.
Parry Smith WR, et al. Uterotonic agents for first-line treatment of postpartum haemorrhage: A network meta-analysis. Cochrane Database of Systematic Reviews.
Refer a patient to Mayo Clinic.