Cesarean Scar Ectopic Pregnancy—The Importance of Ultrasound for Early Detection

Cesarean scar ectopic pregnancy occurs when an embryo implants into or on a prior cesarean scar, and carries a high burden of maternal morbidity and increased risk of maternal mortality when left untreated.1 The estimated incidence is approximately 1 in 1800–2000 pregnancies after cesarean delivery.2 The key to prompt treatment is early identification, most commonly and easily accomplished with transvaginal ultrasound.

Cesarean delivery is the most commonly performed surgery in the world. In the United States, according to the Centers for Disease Control’s Stats of the States data from 2021,  the cesarean delivery rate varies from 24.3% in Utah to a high of 38.3% in Mississippi.3 While cesarean is often a necessary procedure in cases of fetal intolerance of labor, fetal malpresentation, or labor arrest, this surgery impacts future pregnancy, increasing the risks of the need for repeat surgical deliveries, uterine rupture during attempted labor, and placenta accreta spectrum disorders, the latter of which experts now recognize start as cesarean scar ectopic pregnancies.

Following any full-thickness myometrial surgery, just as with any other muscle, the transected myometrial fibers never truly heal together as they once were. Rather, the reapproximated ends are joined by a line of fibrosis, which may partially dehisce, and lack the usual thickness and elasticity of uncompromised myometrium. This scar sometimes retains some structural integrity, but often results in a “niche” or hollowed-out area within the muscle,4,5 where an embryo may implant.

Cesarean scar ectopic pregnancy (CSEP) is easiest to detect sonographically early in the early first trimester, when it can be recognized as a low implantation that is offset more anteriorly than normal, often leaving the endometrial cavity and cervical canal empty.6 Additional criteria for the diagnosis of  CSEP include thin or undetectable myometrium between the placenta and bladder and unusually increased vascularity between the placenta/sac and bladder or internal cervical os. 

Some experts have proposed simple-to-perform measurements, such as the “crossover sign,” whereby a line is drawn in the sagittal plane connecting the internal os with the fundus by drawing a line along the endometrial canal.7 When the superior-inferior diameter of the gestational sac is measured perpendicularly to this line, the relationship of the gestational sac to the endometrial line can be determined.6 In CSEPs in which a majority of the gestational sac is closer to the anterior wall (crosses over the endometrial line), there is a higher rate of severe forms of placenta accreta spectrum and risk for rupture when CSEPs are managed conservatively.7,8

As pregnancy progresses, the gestational sac may grow into the endometrial cavity, making the diagnosis more difficult. Treatment is also more difficult as pregnancy progresses, whereby medical or mechanical management options, such as use of a double balloon catheter are less effective, and surgical resection or combination therapy may be required. The risk of complications including uterine rupture, massive bleeding, and need for emergent hysterectomy that approaches 53% of reported cases are reasons why expectant management is not recommended, especially as early treatment has efficacy rates that are reported between 65% to more than 99% with low complication rates, and with a high likelihood of fertility preservation.  

Early recognition and referral are paramount and provide one more example of how ultrasound can and does save lives.

References:

1. Calì G, Timor-Tritsch IE, Palacios-Jaraquemada J, et al. Outcome of Cesarean scar pregnancy managed expectantly: systematic review and meta-analysis. Ultrasound Obstet Gynecol. 2018; 51:169–175. doi:10.1002/uog.17568

2. Timor-Tritsch IE, Monteagudo A. Unforeseen consequences of the increasing rate of cesarean deliveries: early placenta accreta and cesarean scar pregnancy. A review. Am J Obstet Gynecol 2012; 207:14–29.

3. Centers for Disease Control. Stats of the States – Cesarean Delivery Rates. https://www.cdc.gov/nchs/pressroom/sosmap/cesarean_births/cesareans.htm. Accessed March 30, 2024.

4. Einerson BD, Comstock J, Silver RM, Branch DW, Woodward PJ, Kennedy A. Placenta accreta spectrum disorder: uterine dehiscence, not placental invasion. Obstet Gynecol 2020; 135:1104–1111. doi:10.1097/AOG.0000000000003793.

5. Jauniaux E, Jurkovic D, Hussein AM, Burton GJ. New insights into the etiopathology of placenta accreta spectrum. Am J Obstet Gynecol 2022; 227:384–391. doi:10.1016/j.ajog.2022.02.038.

6. Timor-Tritsch IE, Monteagudo A, Calì G, D’Antonio F, Kaelin Agten A. Cesarean scar pregnancy: diagnosis and pathogenesis. Obstet Gynecol Clin North Am 2019; 46:797–811. doi:10.1016/j.ogc.2019.07.009.

7. Cali G, Forlani F, Timor-Tritsch IE, Palacios-Jaraquemada J, Minneci G, D’Antonio F. Natural history of Cesarean scar pregnancy on prenatal ultrasound: the crossover sign. Ultrasound Obstet Gynecol 2017; 50:100–104. doi:10.1002/uog.16216.

8. Calì G, Calagna G, Khalil A, Polito S, Labate F, Cucinella G, D’Antonio F. First trimester prediction of uterine rupture in cesarean scar pregnancy [published online ahead of print April 20, 2022]. Am J Obstet Gynecol. doi: 10.1016/j.ajog.2022.04.026.

9. Miller R, Gyamfi-Bannerman C. Society for Maternal-Fetal Medicine consult series #63: cesarean scar ectopic pregnancy. Am J Obstet Gynecol 2002 Sep: 227(3):B9–B20. doi: https://doi.org/10.1016/j.ajog.2022.06.024.

Karin A. Fox, MD, MEd, FACOG, FAIUM, is a Professor of Maternal-Fetal Medicine and Director of the Placenta Accreta Spectrum Disorders Program at the University of Texas Medical Branch at Galveston.

Menstrual Pain: Is it Adenomyosis?

Frequently, during daily ultrasound consultations, female patients complain about certain symptoms during their menstrual period, whereas other women go through their monthly cycle without experiencing pain and might feel just a little discomfort associated with their period.Ticci

For those women who do suffer from various common menstrual disorders that can cause stress, pelvic ultrasound is commonly used to investigate any underlying medical problems in menstrual abnormalities.

For example, before speaking with her physician, Brianna didn’t know which symptoms were normal and which were not, since she always thought that a cycle that’s “regular” for her may be abnormal for someone else. She was just chilling at a regular doctor’s checkup when the physician advised her about a vaginal ultrasound after she told him about her symptoms during her menstrual period.

Brianna had never experienced a transvaginal ultrasound before and she thought that it was a little weird and awkward, although some of her friends had told her a while back that the procedure was not painful.

Brianna was referred to my office for the ultrasound exam. She complained about a persistent pelvic pain during her period and about heavy bleeding.

Ultrasound findings:

  • enlarged globular uterus with different densities within the myometrium
  • pockets of fluid within the muscle of the uterus (myometrial cysts)
  • linear acoustic shadowing without the presence of fibroids and echogenic linear striations, like stripes

That’s adenomyosis and it’s very common. And she’s probably never heard of it.

 

 

 

Adenomyosis

Adenomyosis is a common benign gynecologic disorder and its etiology and association with infertility are still unclear. It is a benign disorder previously associated with multiparity but recently, an association with infertility has emerged.

Adenomyosis can be asymptomatic or present with menorrhagia, dysmenorrhea, and metrorrhagia.

Other symptoms may be painful intercourse and/or persistent bladder pressure. These symptoms usually occur in patients aged 35 to 50, and the condition may affect 65% of women.

The patient looked at me while I tried to quell her fears, trying to explain that it is just an unusual thickening of the uterine wall, caused by glandular tissue being pushed into the muscle.

“It’s cancer?” That’s the first question.

“No, it’s not cancer.” I try to explain: it’s something I saw on the ultrasound called adenomyosis and it’s not going to turn into cancer.

The patient probably had never heard that word before and she’s asking how to spell it so she could go home and Google it.

“Is that a bad thing?” That’s the next question.

I answer, “no, it just doesn’t sound like a good thing. ”

 

Adenomyosis and Endometriosis

Brianna is actually very worried at this point. She’s heard the word “Endometriosis” before because some of her female friends have had it and they thought that, perhaps, that was the cause of their fertility problem.

That’s the next question.

“Is adenomyiosis similar to endometriosis?”

I try to explain that endometriosis happens when endometrial cells are outside the uterus. Adenomyosis is when these cells grow into the uterine wall.

This is my answer and I’m trying to reassure my patient that the two syndromes are quite different. Endometriosis is much more severe. Because Brianna remembers that her friends had pregnancy problems, she’s now scared to death.

Pregnancy and fertility, that’s the great issue.

 

Pregnancy and fertility

“Is it possible to get pregnant with Adenomyosis?”

“Don’t be too concerned, Madam” is my answer.

Evidence that links adenomyosis to fertility is limited to case reports and small case series. But there is a significant association between pelvic endometriosis and adenomyosis (54% to 90% of cases), and it is well known that endometriosis causes infertility. For this reason, findings of infertility were due to endometriosis rather than adenomyosis.

At this point in the conversation, I really think that it is very important to calm the patient.

“In most women, it’s not going to have a medical impact. Sometimes, doctors don’t even tell their findings because it’s not really clinically significant,” I say to her.

 

Treatment

Treatment requires a lifelong management plan as the disease has a negative impact on quality of life in terms of menstrual symptoms, fertility, and pregnancy outcome, including a high risk of miscarriage and obstetric complications.

The therapeutic choice depends on the woman’s age, reproductive status, and clinical symptoms. However, so far, few clinical studies focusing on medical or surgical treatment for adenomyosis have been performed, and no drugs labeled for adenomyosis are currently available. Nonetheless, the disease is increasingly diagnosed in young women with reproductive desire, and conservative treatments should be preferred.

Adenomyosis may be considered a sex steroid hormone-related disorder associated with an intense inflammatory process. An antiproliferative effect of progestins suggests their use for treating adenomyosis by reducing bleeding and pain. Continuous oral norethisterone acetate or medroxyprogesterone acetate may help to induce regression of adenomyosis by relieving pain and reducing bleeding.

There is evidence on several surgical approaches for the improvement of adenomyosis-related symptoms; however, there is no robust evidence that they are effective for infertility.

 

 Let’s go back to our office

After this long talk, Brianna realized she didn’t need to freak out.

One thing she really couldn’t understand is why she’d never heard the name of this condition.

She was also kind of upset because she spent her teenage years suffering so much from pelvic pain during periods and now that she’s ready to have a family and give birth, a doctor tells her about an annoying medical condition, gives her all this news that explains all her symptoms, which may cause fertility problems and she’d never heard of it before!

Any suggestions for getting the word out about adenomyosis?

 

Do you have any suggestions for getting the word out about adenomyosis? Do you have your own experience to share? Comment below, or, AIUM members, continue the conversation on Connect, the AIUM’s online community.

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Pietro Ticci, MD, is originally from Florence, Italy, and has been a medical doctor in the Florence Area (Tuscany) since 1995. Currently, he is an Ultrasound Physician at his private medical facilities in the Florence Area.