The risk of blood clots in pregnant mothers is almost ten times more that of a non-pregnant woman. The risk increases even more when the mom-to-be is obese.

According to Lisa Enslow, MSN, RN-BC, Nurse Educator for the Women’s Health and Ambulatory Care Services at Hartford Hospital in Hartford, Connecticut,

“This complication of pregnancy really is affecting a larger amount of patients than ever before. We are seeing our numbers increase. And just that one obesity risk factor can cascade into so many other factors that affect the mom and her baby.”

Lisa joined Pat Iyer, MSN, RN, LNCC, a legal nurse consultant and patient safety expert, to discuss this important issue on the latest Physician-Patient Alliance for Health & Safety (PPAHS) podcast. What follows is a summary of their discussion.


A case study

To illustrate the risks of blood clots in obese pregnant patients, Lisa shared the story of one of her patients. We will call her Mrs. M.

At the time of admission to the hospital, Mrs. M was a thirty-six-years-old woman who was 37 and 3/7 weeks pregnant. She was admitted to have a caesarean delivery (C-section) because of a breech presentation, a condition where the feet or buttocks appear first during birth.

This was her fourth pregnancy. Two of her previous pregnancies were vaginal deliveries and one pregnancy ended in a spontaneous miscarriage. Her living children were seven and twelve years of age and the miscarriage that she had occurred two years previous to this pregnancy.

She was originally scheduled for delivery at thirty-nine weeks but during a routine prenatal exam, her biophysical profile score was four out of ten. That low score plus her reports of a decrease in fetal movement were concerning and prompted consideration of an earlier delivery.


What is the biophysical profile?

The biophysical profile is a measure of fetal well-being in utero. It is obtained via an ultrasound examination and a non-stress test. It consists of five criteria (four from ultrasound and one from a non-stress test):

  1. Fetal movement
  2. Volume of amniotic fluid
  3. Fetal tone
  4. Fetal breathing
  5. Reactivity of a non-stress test

Each of these five criteria is given a maximum score of two, so the highest possible score that a woman can get is a ten. A score of four out of ten warrants labor induction, especially if the gestational age is greater than thirty-two weeks.


Risks of a super obese pregnancy

On admission, Mrs. M denied having contractions, vaginal bleeding, or any leakage of fluid. Her physical examination was notable for marked obesity. Her BMI was 67 which puts her in the category of being super obese defined as a BMI greater than 45 or 50.

This obesity classification puts Mrs. M and her baby at significant risk for a number of complications, including the following:

  • Venous thromboembolism (VTE)
  • Gestational diabetes
  • Infections
  • Difficulty with anesthesia
  • Respiratory compromise
  • Hypertension
  • Pre-eclampsia or eclampsia
  • Having a larger gestational age infant
  • Being overdue
  • Fetal death
  • Caesarean delivery
  • A five-minute Apgar score of less than seven.

Newborns born to super obese moms are likely to be admitted to the neonatal intensive care unit after delivery.


Focusing in on blood clots

As noted above, pregnant women, particularly obese pregnant women, have a higher than average risk of developing venous thromboembolism (VTE) or blood clots in the veins of their legs. When a blood clot in the leg gets dislodged, it can travel to the lungs and cause a serious or even fatal condition, known as pulmonary embolism.

Because of this, Lisa Enslow says, “pregnant patients really need a lot more risk assessments during their hospitalization and even after discharge.”

This patient, Mrs. M. fell into a very high-risk category for VTE because of her pregnancy, obesity, maternal age, and a history of gestational diabetes. Requiring a surgical delivery also increased her risk.


4 keys to reducing risk of blood clots in obese pregnant women

Lisa says there are four keys to reducing the risk of blood clots in obese pregnant women.

1.  Plan for the delivery.

“Pre-planning and communication between all of the team members is really key to achieving the most optimal clinical outcomes for patients with multiple challenging risk factors or individual characteristics. In specialties, such as obstetrics, we’re often faced with a complex patient that requires us to be really proactive and identifying risk factors early in the course of care. This type of preparedness is necessary to prevent adverse events and to identify individual risk factors that would best guide us in the management or plan for patients’ possible hospital-acquired conditions or in adverse event prevention plans to achieve high-quality outcomes.”

2.  Apply blood clot preventative measures.

This patient fell into the high-risk category for venous thromboembolism because of her multiple risk factors, including the high BMI, her gestational diabetes, her maternal age, or having a caesarean section. So, because of this, she was provided with sequential compression devices beginning in the operating room…[The sequential compression devices] stayed on throughout the recovery period in our PACU and also when the patient was transferred to the postpartum unit…We started chemical prophylaxis [blood thinners] six hours following surgery for her and that was continued throughout her stay.”

3.  Preventing blood clots doesn’t stop when the mother leaves the hospital.

It’s important to remember that the commitment to prevent VTE doesn’t end when the patient is discharged. That’s why appropriate patient education is so important to help patients understand why they should comply with their care, with making sure they understand that they really need to continue taking their discharge medications. Our post-partum patients can get the sequential compression devices for use at home and need to keep all their follow-up appointments.”

4.  Use the OB VTE Safety Recommendations.

The OB VTE Safety Recommendations were developed with the advice and counsel of a panel of experts brought together by the Physician-Patient Alliance for Health & Safety. They provide four concise steps that:

  • Assess patients for VTE risk with an easy-to-use automated scoring system.
  • Provide the recommended prophylaxis regimen, depending on whether the mother is antepartum or postpartum.
  • Reassess the patient every 24 hours or upon the occurrence of a significant event, like surgery.
  • Ensure that the mother is provided appropriate VTE prevention education upon hospital discharge.
Pregnancy blood clot risks
Photo credit: PPAHS


Mrs. M’s outcome

Mrs. M was discharged home four days after surgery, typical for C-section patients at this institution. She went home with a sequential compression device and was also told to ambulate as much as possible and to take the blood thinners for six more weeks.

She did not develop VTE and had no other complications from her high-risk pregnancy. She was lucky.

Ms. Enslow concludes, “Caring for Mrs. M. was significantly helped by the guidance from the recently released OB VTE Safety Recommendations, which offers a fine clinical process that covers the entire continuum of care.”

Planning ahead and following evidence-based guidelines were crucial in this case.

The OB VTE Safety Recommendations are a free resource available on the PPAHS website at You can listen to the podcast on YouTube or on iTunesClick here if you would like to read the transcript.

Featured Image Credit:

Michael Wong, JD
Michael Wong, JD is the founder and Executive Director of the Physician-Patient Alliance for Health and Safety (PPAHS). He has been at the forefront in driving practical solutions that reduce healthcare costs, decrease medical errors, and improve patient health outcomes. He has been particularly active in these areas that most affect patient safety: • Improving patient adherence (i.e. helping patients to take their medications as prescribed by their physicians) • Enhancing patient access to healthcare • Reducing medical errors (PPAHS), is an advocacy group of physicians, patient advocates, and healthcare organizations. Supporters of and commenters for PPAHS include highly respected physicians and healthcare organizations, including the The Joint Commission, Anesthesia Patient Safety Foundation, Anesthesia Quality Institute, Johns Hopkins School of Medicine, Harvard Medical School, Stanford University School of Medicine, and the Cleveland Clinic.


  1. You are so interesting! I don’t believe I have
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