AbstractInadvertent Hysterotomy Extension at Cesarean Delivery and Risk of Uterine Rupture in the Next PregnancyOlivia Dumont Manchester-Essex High School, Manchester-by-the-Sea, MATeacher, Dr. Maria Burgess, Manchester-Essex High SchoolMentor, Dr. Henry Barth, Mass General Hosp, Boston, MA

The risk of uterine rupture was looking to be determined for a woman who’s prior incision from a cesarean had an extension. This was examined via a retrospective cohort study of 2385 women who had two cesarean sections in a row or a cesarean and subsequent vaginal birth (VBAC). Among the study group, 271 had an extension of the initial hysterotomy. The risk of uterine rupture for this group was 1.8%, whereas the risk for a woman with a prior cesarean sans an extension is 48%. It was concluded that extension of the incision of a prior cesarean is a significant risk factor by cesarean.

Methods

Subjects: 2385 women with 2 subsequent births (first cesarean and second either vaginal or cesarean) at Mass General Hospital

First Cesarean1. Using the MRN I searched for the op report (c-section 1 ) using OB

LMR2. Hysterotomy extended either bluntly, sharply, or unknown.3. Noted extension of the hysterotomy. (Yes or no) 4. If yes, into the uterus, into the cervix, into the vagina, unilateral,

bilateral, closed with a separate suture, into the bladder, into the broad ligament, into the uterine artery, intentional, or other

5. Sutured with a single, double (imbricating), or unknown number of layers

6. Record suture type. Monocryl, vicryl, chromic, or other.7. Note abnormally adherent placenta, a cystotomy, an enterotomy,

hemorrhage, an extension of the hysterotomy, vascular injury, ureteral injury, uterine rupture, uterine dehiscence, neonatal laceration, or other. These are rare complications

Second Cesarean or Vaginal Birth1. On the same patient record, I noted the second date. Is it a vaginal

birth or c-section? 2. If Vaginal, it was noted and moved on to the next patient.3. If Cesarean, Noted extension of the hysterotomy. (Yes or no)4. If yes, into the uterus, into the cervix, into the vagina, unilateral,

bilateral, closed with a separate suture, into the bladder, into the broad ligament, into the uterine artery, intentional, or other.

5. Sutured with a single, double (imbricating), or unknown number of layers

6. Record suture type. Monocryl, vicryl, chromic, or other. 7. Note abnormally adherent placenta, a cystotomy, an enterotomy,

hemorrhage, an extension of the hysterotomy, vascular injury, ureteral injury, uterine rupture, uterine dehiscence, neonatal laceration, or other. These are rare complications.

8. Note maternal death, infant ICU admission.

Background & Definitions

• Hysterotomy- the cesarean incision into the uterus

• Extension- the accidental uterine incision tear that occurs when a baby is being removed from the uterus

• Uterine rupture- when the myometrial wall and the peritoneum of the uterus break

Extension of the Hysterotomy

Olivia DumontAuthentic Science Research Program Manchester-

Essex Regional High School, Manchester-by-the-Sea, MA 01944

Inadvertent hysterotomy extension at cesarean delivery and risk of uterine rupture in the next pregnancy

Part 1- extension of the uterine incision is a risk factor for uterine rupture during the subsequent pregnancy • Overall, 271 of the 2385 women had an extension with any of the qualities noted

in the methods. There were a total of 5 ruptures in that 271 (1.8%) whereas, there were 10 ruptures in the remaining 2114 women whose incisions were not extended (0.48%).

•

Part 2 - A trial of labor with a hysterotomy extension is a significant risk factor for uterine rupture • The rate of uterine rupture without a hysterotomy extension, but with a trial of

labor was 1.5%, whereas the rate of uterine rupture with a hysterotomy extension and with a trial of labor was 6%.

With extension

Without extension

Without trial of labor

1.8% 0.48%

With trial of labor

6% 1.5%

Analysis of data showed that 271 of 2385, or 11.4%, of women had an extension.

Results

Introduction• Vaginal Birth after Cesarean rates are decreasing rapidly due to risk of

uterine rupture

• Few risk factors for uterine rupture are known

• Difficult to predict the risk of uterine rupture for each individual patient

• Our research works to determine whether the unintentional extension of the uterine incision with and without a trial of labor is a risk factor for uterine rupture

AcknowledgmentsI would like to thank my three mentors, Dr. Ilona Goldfarb, Dr. William Barth (Chief of Maternal Fetal Medicine), and Dr. Dana Henry from Mass General and Brigham and Women’s Hospitals. They went out of their way to provide me with an incredible, unique, informative and irreplaceable experience. I couldn’t thank them enough! Also supported by a grant from the Spaulding Educational Fund.

Future ResearchUsing the database we have we could ask a series of other

research questions.

• What is the effect of the extension on pre-term birth?-Pre-term birth can be detrimental.

-Surfactants and lung development.

• Is the suture type a predictor of uterine rupture?-Monocryl, Vicryl, or Chromic

• Is blunt vs. sharp extension a risk factor for uterine rupture?

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Figure 1. Surgically-repaired vertical hysterotomy of uterus, post-birth.