Management of early pregnancy loss

Definition, Purpose and Scope

The term early pregnancy loss describes the loss of pregnancy within the first 12 completed gestational weeks. It primarily refers to the management of spontaneous miscarriage, but it is also relevant to women affected by ectopic pregnancy and gestational trophoblastic disease.

Spontaneous miscarriage is the most common complication of pregnancy. It occurs in up to 20% of clinically recognized pregnancies. In Ireland, approximately 14,000 miscarriages occur each year [Poulose et al., 2006].

Historically, the majority of women who experienced miscarriage underwent routine surgical uterine evacuation, known as evacuation of retained products of conception (ERPC). Over the last decade, standard management has changed significantly due to the development of more refined diagnostic techniques and therapeutic interventions. These advances have enabled a greater proportion of treatment to be delivered in an outpatient setting.

Service Provision in Early Pregnancy Assessment Units (EPAU)

All maternity units should provide a dedicated Early Pregnancy Assessment Unit (EPAU) for the evaluation of women presenting with early pregnancy complications.

All women attending an EPAU should receive a diagnosis and be classified into one of the following diagnostic categories:

Diagnostic Groups

Viable pregnancy
Pregnancy of uncertain viability
Early pregnancy loss
Incomplete miscarriage
Complete miscarriage
Pregnancy of unknown location (PUL)
Ectopic pregnancy
Hydatidiform mole

Ultrasound Criteria for Early Pregnancy Loss

According to the Royal Institute of Obstetricians, the College of Physicians of Ireland, and the Directorate of Strategy and Clinical Programmes of the Health Service Executive, early pregnancy loss is diagnosed when one or more of the following criteria are met:

Transvaginal Ultrasound (TVS) Criteria

Mean gestational sac diameter (MGSD) > 20 mm with no fetal pole
Fetal pole > 7 mm with no fetal cardiac activity

Transabdominal Ultrasound (TAS) Criteria

MGSD > 25 mm with no fetal pole
Fetal pole > 8 mm with no fetal cardiac activity

Criteria Based on Repeat Ultrasound Examination

MGSD ≤ 20 mm with no fetal pole, or fetal pole ≤ 7 mm with no cardiac activity on TVS, with minimal or no growth after at least 7 days
MGSD ≤ 25 mm with no fetal pole, or fetal pole ≤ 8 mm with no cardiac activity on TAS, with minimal or no growth after at least 7 days

It is important to recognize that interobserver and intraobserver variability in MGSD and fetal pole measurements can reach ±18% [Pexsters et al., 2011]. Therefore, repeated ultrasound examinations are strongly recommended, particularly when measurements are close to diagnostic thresholds.

Other Diagnostic Categories pregnancy loss

Viable Intrauterine Pregnancy

A viable pregnancy is defined by the presence of a normally located gestational sac with a fetal pole and clearly identifiable cardiac activity. Detection of fetal heart activity is associated with a successful pregnancy rate of 85–97%, depending on gestational age [Johns et al., 2003].

Follow-up may be required in cases of:

Significant vaginal bleeding
Subchorionic haematoma
Fetal bradycardia
Patient reassurance following previous miscarriages
Recent removal of an intrauterine contraceptive device

Pregnancy of Uncertain Viability

This diagnosis is made when:

A normally located gestational sac with MGSD ≤ 20 mm and no fetal pole is observed, or
A fetal pole ≤ 7 mm is present without cardiac activity on TVS [Clinical Practice Guideline, 2011].

A repeat scan should be performed at least 7 days later to assess embryonic development and cardiac activity.

Incomplete Miscarriage

An incomplete miscarriage is diagnosed when the intrauterine tissue diameter is ≥ 15 mm on ultrasound.

Complete Miscarriage

A complete miscarriage is diagnosed when endometrial thickness is < 15 mm and there is previous evidence of an intrauterine gestational sac or retained products of conception.

Pregnancy of Unknown Location (PUL)

PUL is diagnosed when no evidence of intrauterine or extrauterine pregnancy is detected in a woman with a positive pregnancy test.

Possible explanations include:

Very early intrauterine pregnancy
Complete miscarriage
Early ectopic pregnancy

Even with expert ultrasound assessment, the location of pregnancy cannot be determined in 8–31% of cases at the initial visit [Condus et al., 2003].

Silent Miscarriage

Wilcox et al. (1988) demonstrated that 31% of pregnancies were lost after implantation. Using sensitive hCG assays, two-thirds of these losses were clinically silent.

Aetiology of Early Pregnancy Loss

Fetal Factors

Chromosomal abnormalities are the most common cause of early miscarriage. Their incidence increases with maternal age, particularly after 35 years. Approximately 95% of chromosomal abnormalities originate from maternal gametogenesis, while 5% originate from paternal factors. Autosomal trisomy is the most frequently identified chromosomal anomaly.

Paternal Factors

Balanced chromosomal translocations
Aging sperm

Maternal Factors

Endocrine disorders (hypothyroidism, diabetes mellitus)
Chronic debilitating diseases (tuberculosis, malignancy)
Nutritional deficiencies
Immunological disorders
Inherited thrombophilias
Drug use and environmental factors (tobacco, alcohol, radiation)
Uterine anomalies and submucosal fibroids
Infections (Chlamydia, Mycoplasma)

According to the American College of Obstetricians and Gynecologists (2001), infections are an uncommon cause of early miscarriage. Oakeshott et al. (2002) reported an association between bacterial vaginosis and second-trimester miscarriage.

Clinical Assessment in the EPAU

A brief history should include:

Previous obstetric history
Last menstrual period (LMP)
Urine pregnancy test result
Presence and characteristics of pain
Presence and severity of bleeding
Passage of products of conception

Clinical examination should be performed when indicated.

In the absence of clinical symptoms, ultrasound examination before 8 weeks of gestation should be discouraged, as early scanning may increase anxiety rather than reassurance.

Diagnostic Investigations

Ultrasound Examination

TVS is required in most women attending an EPAU.

Indications for Repeat Ultrasound

Initial scan performed before 8 weeks
Scan performed by an untrained operator
Doubts about scan reliability
Long or irregular menstrual cycle
Patient request

Serial Serum hCG Measurement

Serial hCG testing is particularly useful in diagnosing ectopic pregnancy and PUL. Levels above 1500 IU/L usually allow visualization of ectopic pregnancy on TVS.

Serum Progesterone

Serum progesterone levels below 25 nmol/L are associated with non-viable pregnancies, while levels above 60 nmol/L strongly correlate with ongoing pregnancies.

Conservative Management of Miscarriage

Conservative management is appropriate when there are no signs of infection, excessive bleeding, fever, or abdominal pain. Women should be counselled regarding expected symptoms and analgesia.

Medical Management of Miscarriage

Misoprostol is an effective prostaglandin analogue used orally or vaginally. Women should be informed about potential side effects and the possibility of surgical intervention if heavy bleeding occurs.

Surgical Management of Miscarriage

ERPC should be offered based on clinical indications or patient preference. Vacuum aspiration is preferred over sharp curettage due to lower blood loss and shorter procedure duration.

Rhesus Anti-D Prophylaxis

Anti-D immunoglobulin should be administered to non-sensitized Rh-negative women in specific clinical scenarios, including ectopic pregnancy and miscarriages beyond 12 weeks of gestation.