>Spontaneous Abortion

Medical Student Clinical Pearl

Miranda Lees, Clinical Clerk II

Dalhousie Medicine New Brunswick, Saint John

Reviewed by Dr. Mandy Peach

Case

A 21yo G3P1A1 female at 6 weeks gestation presented to the Emergency Department with an 8 hour history of vaginal bleeding and abdominal pain. The bleeding is a mixture of bright red and brown blood with no clots, and the abdominal pain is episodic cramping in her suprapubic region.

Her obstetrical history is significant for 2 prior pregnancies, the first of which was carried to term with an uncomplicated vaginal delivery, and the second of which had resulted in a spontaneous abortion at 6 weeks gestation. She is otherwise healthy. The patient noted with both prior pregnancies she had similar vaginal bleeding around 6-8 weeks gestation. She was given RhoGAM due to her Rh- blood type.

On assessment the patient appeared well with all vital signs within normal limits. On physical exam bowel sounds were present, the abdomen was tympanic to percussion, and pain on palpation was present in the patient’s suprapubic region.

 

Differential for life threatening causes of vaginal bleeding in pregnancy

<20 weeks gestation >20 weeks gestation
      ruptured ectopic pregnancy          placental abruption
       retained products of conception          placenta previa
       complication of termination          post partum hemorrhage

Other causes for vaginal bleeding to consider in pregnancy and in non-pregnant patients

Spontaneous abortion
Acute heavy menstrual bleeding
Genitourinary trauma
Uterine arteriovenous malformation
Ruptured ovarian cyst
Ovarian torsion
Pelvic Inflammatory Disease
Fibroids
Polyps
Foreign body
Coagulation disorder
Medication related
Gynecologic malignancy

 

Investigations

A βhCG was ordered to confirm pregnancy and bedside ultrasound was done to look for intrauterine pregnancy.

Transabdominal ultrasound showed the following:

The presence of a gestational sac within the uterus and a fetal heartbeat within the fetal pole confirmed a viable intrauterine pregnancy (IUP). The patient was diagnosed with threatened abortion.

 

Spontaneous Abortion-an overview

Spontaneous abortion is one of the most common complications of pregnancy, occurring in 17-22% of pregnancies2 and is defined as loss of pregnancy prior to 20 weeks gestation, occurring most often in the first trimester3. There are 3 primary causes: chromosomal abnormalities in the fetus, maternal anatomic abnormalities, and trauma.3

Risk factors for spontaneous abortion

age (below 20 and above 35)
moderate to severe bleeding (especially if passage of clots)
prior pregnancy loss
maternal comorbidities (DM, autoimmune conditions, obesity, thyroid disease)
infection (notably parvovirus, CMV and untreated syphilis)
teratogenic medications
maternal radiation exposure
maternal smoking
caffeine
alcohol use

 

Classification4

Missed abortion is characterized by an asymptomatic death of the fetus with a lack of contractions to push out the products of conception.5

Clinical presentation

Spontaneous abortion most commonly presents with vaginal bleeding and cramping, ranging from mild to severe1. However, most women with first-trimester bleeding will not undergo spontaneous abortion1. Bleeding associated with spontaneous abortion often involves passage of clots or fetal tissue, and the cramping can be constant or intermittent, often worse with passage of tissue1.

Diagnosis

Confirmation of spontaneous abortion requires pelvic ultrasound.

In patients with a prior ultrasound showing intrauterine pregnancy, diagnosis of spontaneous abortion can be made if a subsequent ultrasound shows no intrauterine pregnancy or a loss of previously-seen fetal heartbeat1.

In patients with a prior ultrasound showing intrauterine pregnancy with no fetal heartbeat, spontaneous abortion is diagnosed based on the following1:

  • A gestational sac >25mm in diameter containing no yolk sac or embryo
  • An embryo with crown rump length >7mm with no fetal cardiac activity
  • After pelvic ultrasound showing a gestational sac without a yolk sac, absence of embryo with a heartbeat in >2 weeks
  • After pelvic ultrasound showing a gestational sac with a yolk sac, absence of embryo with a heartbeat in >11 days

Case conclusion

The patient was treated with IM RhoGAM, a formal pelvic and transvaginal ultrasound was arranged for the next day, and she was discharged home. The follow-up ultrasound showed a gestational sac present in the uterus, an embryo with crown rump length of 8.1mm and the presence of a fetal heartbeat.

 

References

  1. Borhart D. Approach to the adult with vaginal bleeding in the Emergency Department. In: UptoDate, Hockberger R (Ed), UpToDate, Waltham, MA. (Accessed on October 8, 2020).
  2. Gracia C, Sammel M, Chittams J, Hummel A, Shaunik A, et al. Risk Factors for Spontaneous Abortion in Early Symptomatic First-Trimester Pregnancies. Obstetrics & Gynecology. 2005;106(5):993-999. doi 1097/01.AOG.0000183604.09922.e0.
  3. Prager, Mikes & Dalton. Pregnancy loss (miscarriage): Risk factors, etiology, clinical manisfestations, and diagnostic evaluation. In: UptoDate, Eckler (Ed), UptoDate, Waltham MA. (accessed Nov 28, 2020)
  4. Diaz. 2018. Types of Spontaneous Abortion. In: GrepMed. Image Based Medical Reference. https://www.grepmed.com/images/5425/classification-spontaneous-obstetrics-diagnosis-abortion-obgyn-types (Accessed Nov 28, 2020)
  5. Alves C, Rapp A. Spontaneous Abortion (Miscarriage) [Updated 2020 Jul 20]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560521/.

 

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