Pelvic pain in first trimester – differential diagnosis

13th Decemer 2022, NIA Diagnostic Imaging

Pelvic pain

Pelvic pain is a common presentation in general practice. It becomes a little bit more complicated if that occurs during the first trimester of pregnancy. To the usual gynaecological and non-gynaecological causes, we have to add the other obstetric causes of pelvic pain. The obstetric causes during the 1st trimester can be a serious concern and should be treated as an urgent matter. Often we need to order an urgent pelvic ultrasound. NIA Diagnostic Imaging always prioritise urgent pregnancy cases by offering same-day appointments and reports. They also have a team of highly knowledgeable male and female sonographers and radiologists who specialise in women’s imaging to deliver accurate and fast diagnosis.

Different diagnoses for pelvic pain in the 1^st trimester includes:

Subchorionic hemorrhage*
Spontaneous abortion*
Molar pregnancy
Benign ovarian cyst
- Corpus luteam*
- Follicular
- Haemorrhagic
- Endometriotic
Haemoperitoneum
Ectopic pregnancy*
Ovarian hyperstimulation
Ovarian torsion
Leiomyoma (Fibroids)
Urinary tract
- Hydronephrosis
- Cystitis
- Pyelonephritis
- Nephrolithiasis (renal stones)
Gastrointestinal
- Appendicitis
- Crohn’s disease
Bowel obstruction

(Eyvazzadeh & Levine, 2006) (Masselli, et al., 2014)

From the above list, the ones with an asterisk will be the ones we will discuss further.

Subchorionic Haemorrhage Aetiology

Subchorionic haemorrhages is bleeding under the chorion membranes and occurs when the trophoblast partially detaches from the uterine wall (Bondick, et al., 2021).

The causes of subchorionic haemorrhages are still unclear. However, malformations of the uterus, history of miscarriages or pelvic infections are factors that can contribute to a subchorionic haemorrhage (Bondick, et al., 2021).

Pathology/Pathophysiology

It is suggested that subchorionic haemorrhages occurs when the utero-placental veins tear and leads to low pressure bleeding that tracks around the gestational sac and forms a crescent-shaped haematoma between the chorion membrane and uterine wall (Zhen, 2017).

Ectopic Pregnancy Aetiology

Ectopic pregnancies occurs when a blastocyst implants outside of the endometrial canal.

The risk factors include history of ectopic pregnancy, tubal surgery, and pelvic inflammatory disease (University of Washington, 2022).

Pathology/Pathophysiology

After 6 to 16 weeks, the structure containing the foetus ruptures and this rupture can gradually or rapidly cause haemorrhagic shock. A delayed rupture can lead to more rapid blood lost and higher risk of death (Dulay, 2020).

97% of ectopic pregnancies occur in the fallopian tubes. However, they can also be found elsewhere, and this is well demonstrated in Figure 1.

Spontaneous Abortion Aetiology

Spontaneous abortion is the natural loss of pregnancy before 20 weeks gestation and occurs in 10-12% of clinically recognised pregnancies (Alves & Rapp, 2021) (Eyvazzadeh & Levine, 2006). It is believed that in 50% of cases, it is because of foetal chromosomal abnormalities that lead to spontaneous abortions (Alves & Rapp, 2021).

Pathology/Pathophysiology

Spontaneous abortions can be categorised in 5 forms:

Threatened miscarriage: bleeding in the first 20 weeks of gestation with a closed internal os (Eyvazzadeh & Levine, 2006)
Missed miscarriage: non-viable intrauterine foetus with no symptoms of a miscarriage (Weerakkody, 2022)
Inevitable miscarriage: bleeding in the first 20 weeks of gestation with an open internal os. In this case, the gestational sac may be seen low lying within the uterus and will need serial ultrasound to observe migration progress (Jones, 2021)
Incomplete miscarriage: intrauterine miscarriage where the retained product of conception is still within the uterus (Jones, 2021)
Complete miscarriage: intrauterine miscarriage where there are no retained products of conception within the uterus and vaginal bleeding has ceased (Jones, 2021)

Corpus Luteum Aetiology

A corpus luteum is an ovarian cyst that forms during the luteal phase.

When the corpus luteal cyst undergoes haemorrhage, twists or ruptures, these occurrences can cause pelvic pain for the patient (Eyvazzadeh & Levine, 2006).

Pathology/Pathophysiology

Once the cyst is formed, blood fills the cyst and eventually forms a haemorrhagic corpus luteal cyst which may rupture. When the corpus luteal cyst ruptures, it leads to internal bleeding in the peritoneal cavity and this bleeding irritates the surrounding anatomy and leads to pelvic pain (Medvediev, et al., 2020).

At NIA Diagnostic Imaging, they thrive to put in time to thoroughly investigate the source of the problem and provide the most accurate diagnosis.

References

Alves, C & Rapp, A 2021, Spontaneous Abortion, StatPearls Publishing, Treasure Island, Florida.

Bondick, C, Das, J & Fertel, H 2021, Subchorionic Hemorrhage, StatPearls Publishing, Treasure Island, Florida. Dulay, A 2020, Ectopic Pregnancy, MSD Manual, New York, USA.

Eyvazzadeh, A & Levine, D 2006, Imaging of Pelvic Pain in the First Trimester of Pregnancy. Radiologic Clinics of North America, vol. 44, no. 6, pp. 863-877.

Institute of Obstetricians and Gynaecologists, Royal College of Physicians of Ireland 2010, Ultrasound Diagnosis of Early Pregnancy Miscarriage, Health Service Executive, Dublin, Ireland.

Jones, J 2021, Complete miscarriage, viewed 10 April 2022, <https://radiopaedia.org/articles/complete- miscarriage?lang=gb>.

Jones, J 2021, Incomplete miscarriage, viewed 10 April 2022, <https://radiopaedia.org/articles/incomplete- miscarriage?lang=gb>.

Jones, J 2021, Inevitable miscarriage, viewed 10 April 2022, <https://radiopaedia.org/articles/inevitable- miscarriage?lang=gb>.

Lin, E, Bhatt, S & Dogra, V 2008, Diagnostic Clues to Ectopic Pregnancy. Radiographics, vol. 28, no. 6, pp. 1661-1671. Masselli, G. et al 2014, Imaging for acute pelvic pain in pregnancy. Insights Imaging, vol. 5, no. 2, pp. 165-181.

Medvediev, M. V, Malvasi, A, Gustapane, S & Tinelli, A 2020, Hemorrhagic corpus luteum: Clinical management update.

Turkish Journal Of Obstetrics And Gynecology, vol. 17, no. 4, pp. 300-309.

Ucisik-Keser, F. E. et al 2021, The many faces of ectopic pregnancies: demystifying the common and less common entities. Abdominal Radiology, vol. 46, no. 3, pp. 1104-1114.

University of Washington, 2022, Department of Radiology, viewed 10 April 2022, <https://rad.washington.edu/body- teaching-files/23742/>.

Weerakkody, Y 2022, Missed miscarriage, viewed 10 April 2022, <https://radiopaedia.org/articles/missed- miscarriage-2?lang=gb>

Zhen, L. D 2017, Effects of subchorionic haematoma on pregnancy outcomes, Australian Medical Student Journal, Melbourne, Australia.

PFO Closure

Furlan AJ, Reisman M, Massaro J, et al. Closure or medical therapy for cryptogenic stroke with patent foramen ovale. N Engl J Med 2012; 366: 991–

A multicenter, randomized, open-label trial of closure with a percutaneous device, as compared with medical therapy alone, in patients between 18 and 60 years of age who presented with a cryptogenic stroke or transient ischemic attack (TIA) and had a patent foramen ovale. The primary end point was a composite of stroke or transient ischemic attack during 2 years of follow-up, death from any cause during the first 30 days, or death from neurologic causes between 31 days and 2 years.

Results:

Primary end point was 5.5% in the closure group as compared with 6.8% in the medical-therapy group (adjusted hazard ratio, 0.78; 95% confidence interval, 0.45 to 1.35; P = 0.37)

Conclusion:

“In patients with cryptogenic stroke or TIA who had a patent foramen ovale, closure

with a device did not offer a greater benefit than medical therapy alone for the

prevention of recurrent stroke or TIA”

2 Saver JL, Carroll JD, Thaler DE, et al. Long-term outcomes of patent foramen ovale closure or medical therapy after stroke. N Engl J Med 2017; 377: 1022–

A multicenter, randomised, open-label trial ,randomly assigned patients 18 to 60 years of age who had a patent foramen ovale (PFO) and had had a cryptogenic ischemic stroke to undergo closure of the PFO (PFO closure group) or to receive medical therapy alone (aspirin, warfarin, clopidogrel, or aspirin combined with extended-release dipyridamole; medical-therapy group). The primary efficacy end point was a composite of recurrent nonfatal ischemic stroke, fatal ischemic stroke, or early death after randomisation.

Results:

Recurrent ischemic stroke occurred in 18 patients in the PFO closure group and in 28 patients in the medical-therapy group, resulting in rates of 0.58 events per 100 patient-years and 1.07 events per 100 patient years, respectively (hazard ratio 0.55; 0.31 – 0.999; P = 0.046)

Conclusion:

“Among adults who had had a cryptogenic ischemic stroke, closure of a PFO was associated with a lower rate of recurrent ischemic strokes than medical therapy alone during extended follow-up.”

Meier B, Kalesan B, Mattle HP, et al. Percutaneous closure of patent foramen ovale in cryptogenic embolism. N Engl J Med 2013; 368: 1083–

A prospective, multicenter, randomised, event-driven trial, randomly assigned patients to medical therapy alone (anti-platelet or warfarin therapy) or closure of the patent foramen ovale.

Results:

9 patients in the closure group and 16 in the medical-therapy group had a recurrence of stroke (hazard ratio with closure, 0.49; 0.22 – 1.11; P = 0.08). The primary analysis of the intentionto- treat cohort showed a nominal 51% hazard rate reduction with closure, but the reduction did not reach significance.

Conclusions:

” …there was no significant benefit associated with closure of a patent foramen ovale in adults who had had a cryptogenic ischaemic stroke.”

Sondergaard L, Kasner SE, Rhodes JF, et al. Patent foramen ovale closure or antiplatelet therapy for cryptogenic stroke. N Engl J Med 2017; 377: 1033–

Multinational trial involving patients with a PFO who had had a cryptogenic stroke, randomly assigned patients to undergo PFO closure plus antiplatelet therapy or to receive antiplatelet therapy alone.

Results:

During a median follow-up of 3.2 years, clinical ischemic stroke occurred in 6 of 441 patients (1.4%) in the PFO closure group and in 12 of 223 patients (5.4%) in the antiplatelet-only group (hazard ratio, 0.23; 0.09 to 0.62; P=0.002).

Conclusions:

“Among patients with a PFO who had had a cryptogenic stroke, the risk of subsequent ischemic stroke was lower among those assigned to PFO closure combined with antiplatelet therapy than among those assigned to antiplatelet therapy alone; however, PFO closure was associated with higher rates of device complications and atrial fibrillation.”

Mas JL, Derumeaux G, Guillon B, et al. Patent foramen ovale closure or anticoagulation vs. antiplatelets after stroke. N Engl J Med 2017; 377: 1011–

In a multicenter, randomised, open-label trial patients 16-60 years of age who had had a recent stroke attributed to PFO, to transcatheter PFO closure plus long-term antiplatelet therapy, antiplatelet therapy alone or oral anticoagulation.

Results:

No stroke occurred among patients in the PFO closure group, whereas stroke occurred in 14 of the 235 patients in the antiplatelet- only group (hazard ratio, 0.03; 0 to 0.26; P<0.001). Large number of patients discontinued anti-coagulation in the anti-coagulant group and statistical significance was not analysed because the study was not adequately powered to compare outcomes.

Conclusion:

“Among patients who had had a recent cryptogenic stroke attributed to PFO with an associated atrial septal aneurysm or large interatrial shunt, the rate of stroke recurrence was lower among those assigned to PFO closure combined with antiplatelet therapy than among those assigned to antiplatelet therapy alone. PFO closure was associated with an increased risk of atrial fibrillation.”

Lee PH, Song J-K, Kim JS, et al. Cryptogenic stroke and high-risk patent foramen ovale: the DEFENSE-PFO Trial. J Am Coll Cardiol 2018; 71: 2335–

Patients with cryptogenic stroke and high-risk PFO were divided between a transcatheter PFO closure and a medication-only group.

Results:

No events occurred in the PFO closure group. 12.9% of patients in the medication group had an event (p= 0.023).

Conclusion:

“PFO closure in patients with high-risk PFO characteristics resulted in a lower rate of the primary endpoint as well as stroke recurrence”