Table of contents
Expand All Topics
Early pregnancy loss
What's new
The Society of Obstetricians and Gynaecologists of Canada (SOGC) has released a new guideline on early pregnancy loss (EPL). Ultrasound criteria should be used to diagnose intrauterine EPL, and reliance on β-hCG values alone should be avoided due to overlap with non-viable intrauterine pregnancy, viable intrauterine pregnancy, and ectopic pregnancy. For stable patients, expectant, medical, and surgical options should be discussed, with expectant management preferred for incomplete loss without heavy bleeding or infection. Mifepristone plus misoprostol, or misoprostol alone, is recommended for medical management when a gestational sac is present. Suction curettage is the preferred method for surgical management. Routine RhD immune globulin is not recommended for losses under 12 weeks. .
Background
Overview
Definition
Early pregnancy loss is defined as the spontaneous loss of a pregnancy before 13 weeks of gestation.
1
Pathophysiology
The majority of early pregnancy losses are due to chromosomal abnormalities, found in approximately 50-82% of cases. The most common are autosomal trisomies, particularly trisomy 15, 16, 21, and 22, along with triploidy, monosomy X, and structural rearrangements. These losses typically occur between 5 and 9 weeks of gestation. Immunologic factors, such as impaired regulatory T cell function or abnormal endometrial decidualization, can disrupt maternal tolerance of the fetus and contribute to EPL. Infections including CMV, HIV, rubella, and malaria have also been implicated, through direct placental infection, immune-mediated disruption, or maternal systemic illness.
1
Epidemiology
Early pregnancy loss occurs in approximately 10-20% of clinically recognized pregnancies, with about 80% of losses taking place during the first trimester. The true incidence is likely underestimated, as many early miscarriages are not clinically diagnosed and may be misattributed to delayed or heavy menstrual bleeding.
1
Risk factors
Advanced maternal age is a major nonmodifiable risk factor for early pregnancy loss, with risk increasing significantly after age 35 and reaching over 50% by age 45. Other maternal factors include a prior history of early pregnancy loss, adverse outcomes in previous pregnancies (such as preterm birth, stillbirth), and Black ethnicity. Structural uterine anomalies, such as septate, bicornuate, or unicornuate uteri, as well as fibroids, endometrial polyps, intrauterine adhesions, and subchorionic hematoma increase the likelihood of early pregnancy loss. Endocrine disorders, particularly poorly controlled diabetes, PCOS, and thyroid disease, are associated with higher rates of early pregnancy loss. Among autoimmune conditions, antiphospholipid syndrome and SLE are most clearly associated with recurrent losses. Modifiable risk factors include extremes in BMI, smoking, alcohol or illicit drug use, certain medications (such as prolonged NSAIDs use around conception), and environmental exposures such as air pollution and pesticides.
2
3
Disease course
Early pregnancy loss most commonly presents with vaginal bleeding, pelvic cramping, abdominal pain, or passage of tissue. Bleeding may range from light spotting to heavy flow with clots or tissue and is often accompanied by lower abdominal or pelvic pain. The combination of moderate to heavy bleeding and cramping is strongly associated with early pregnancy loss. While most patients with early pregnancy loss experience symptoms, up to 38% may be asymptomatic, with pregnancy loss detected incidentally by ultrasound. This form, previously termed missed abortion, is now described as an asymptomatic incomplete abortion.
1
3
Prognosis and risk of recurrence
The prognosis after early pregnancy loss is generally favorable, with severe complications such as hypovolemic shock and septic miscarriage being rare. Fewer than 5% of patients experience two consecutive losses, and only about 1% have three or more.
1
Guidelines
Key sources
The following summarized guidelines for the evaluation and management of early pregnancy loss are prepared by our editorial team based on guidelines from the Society of Obstetricians and Gynaecologists of Canada (SOGC 2025), the American Academy of Family Physicians (AAFP 2021,2019), and the American College of Obstetricians and Gynecologists (ACOG 2018).
1
2
3
4
5
6
7
Diagnostic investigations
Ultrasound: as per SOGC 2025 guidelines, use ultrasound criteria to diagnose intrauterine early pregnancy loss.
A
More topics in this section
hCG
Screening for depression
Medical management
General principles: as per SOGC 2025 guidelines, discuss all available management options, including expectant, medical, and procedural, for stable patients with early pregnancy loss without signs of infection.
A
Show 3 more
More topics in this section
Misoprostol and mifepristone
RhD immune globulin
Therapeutic procedures
Perioperative care
Patient education
General counseling
As per SOGC 2025 guidelines:
Counsel patients with no prior history of early pregnancy loss that no known treatment can alter the outcome of a threatened early pregnancy loss.
A
Take into consideration patient health history, including anemia and bleeding disorders, and proximity to a healthcare facility capable of managing urgent and emergent complications when counseling patients on management options.
A
Preventative measures
Follow-up and surveillance
Follow-up
As per SOGC 2025 guidelines:
Obtain clinical follow-up for a definite intrauterine early pregnancy loss managed expectantly or medically that results in heavy bleeding which subsequently resolves. Reserve ultrasound and β-hCG levels for clinical concerns such as ongoing heavy bleeding, suspected infection, spotting for > 3 weeks, or amenorrhea for > 8 weeks.
B
Offer a reassurance ultrasound at 7 weeks gestational age to pregnant patients who have experienced a prior early pregnancy loss to confirm pregnancy location and viability.
B