Threatened Early Pregnancy Loss Due to Subchorionic Hematoma: When Bleeding Threatens Viability

Case Report

Patient Evaluation

Physical Examination

On examination, she was hemodynamically stable with stable vital signs. She used a regular sanitary pad once daily, indicating light bleeding. General examination showed mild pallor, with no icterus, cyanosis, clubbing, or edema.

• Abdominal exam: Soft, non-distended; uterus not palpable; no tenderness
• Speculum exam: Minimal fresh bleeding in vault, bright red and scanty; cervix healthy and pink with closed external os
• Bimanual exam: Uterus size consistent with 8–10 weeks, soft (Hegar's sign present); cervix firm and closed; fornices free and non-tender

Investigations

Transvaginal ultrasound revealed a single live intrauterine pregnancy with CRL measuring approximately 8 weeks and 5 days and FHR of 170 bpm. A small subchorionic hematoma (SCH) of 4.2 cc volume was present. The cervical internal os was partially open (~8 mm), with the external os closed and cervical canal ~35 mm long.

Investigation	Result
Serum β-hCG	Appropriate for gestational age
Hemoglobin / WBC / Platelets	Normal; no leukocytosis
Urine routine	Normal
Serum progesterone	15 ng/mL
TSH / FBS / RBS	Within normal limits

Differential Diagnosis

Based on the history, examination, and investigations, the following diagnoses were considered:

• Missed abortion
• Inevitable abortion
• Incomplete abortion
• Ectopic pregnancy
• Molar pregnancy
• Local cervical causes

Final Diagnosis & Management

The patient was managed conservatively with expectant care and prescribed:

• Folic acid
• Alpha-lipoic acid (600 mg/day — 300 mg twice daily)
• Dydrogesterone 30 mg/day
• Close monitoring with follow-up ultrasound

She was counselled regarding the potential risks and instructed to return immediately for heavy bleeding, severe abdominal pain, or fever.

Outcome

A follow-up ultrasound at 2 weeks showed a single live embryo within a well-formed intrauterine gestational sac with appropriate choriodecidual reaction. CRL was 37 mm (~10 weeks 4 days ± 4 days); embryonic cardiac activity was normal at 164 bpm. The cervical os was closed.

Her bleeding gradually subsided, and subsequent ultrasounds confirmed a healthy pregnancy without further issues.

Discussion

Threatened abortion, or threatened miscarriage, occurs when vaginal bleeding with or without cramping develops in early pregnancy while the cervix remains closed. It is the most common complication of early pregnancy and is often associated with considerable anxiety and emotional stress. It occurs in approximately 20% of recognized pregnancies, and about half of these cases ultimately end in miscarriage.

Threatened miscarriage results from partial detachment or bleeding of the decidua or chorion while the pregnancy remains viable. Common mechanisms include subchorionic hemorrhage and disruption of the implantation process. In some women, inadequate luteal function and low progesterone levels may impair decidualization and myometrial quiescence, thereby increasing the risk of bleeding and subsequent pregnancy loss.

Diagnosis

Clinically, threatened miscarriage is diagnosed in women with first-trimester bleeding, a closed cervical os, and ultrasound evidence of a viable intrauterine pregnancy. Key investigations include:

• Serial serum β-hCG to assess trends
• Progesterone levels (<10 ng/mL indicates higher risk of miscarriage)
• Baseline hemoglobin/hematocrit, blood group and Rh status
• Transvaginal ultrasound to confirm FHR, CRL, GSD, and SCH

Subchorionic Hematoma (SCH)

SCH is defined as a blood collection between the chorion and uterine wall, commonly associated with first-trimester bleeding and threatened abortion. It occurs in approximately 18–22% of pregnancies and is a common cause of first-trimester bleeding.

SCH Grade	Size Relative to Gestational Sac	Risk
Small	<10–20% of GS	Lower risk
Medium	20–50% of GS	Moderate risk
Large	>50% of GS	Higher risk of loss/preterm labor

SCH detected at ≤7–8 weeks is associated with higher pregnancy loss rates than later detection (e.g., 19.6% vs. 3.6% when detected ≤7 vs. >8 weeks).

Predictive Ultrasound Findings

Finding	Cutoff	Prognosis Impact
Absent FHR	No cardiac activity	Imminent miscarriage
Low FHR	<100–113 bpm	17–30% miscarriage risk
Small GSD	<15 mm	Poor viability
Small CRL	<19.9–22 mm	High risk of progression to loss
Irregular sac walls	Irregular shape	Increased miscarriage odds
Large yolk sac	Above cutoff diameter	Complications if persists
SCH	Large perigestational hemorrhage	Grade/GA-dependent risk

An FHR >113 bpm, CRL >19.9 mm, and GSD >27.3 mm predict continuation to 28 weeks with 98% specificity and 99% positive predictive value.

Management of Threatened Abortion

Most cases are managed expectantly on an outpatient basis after excluding ectopic and nonviable pregnancy. Patients should be advised to return if bleeding increases, pain worsens, or tissue is passed, and repeat ultrasonography is indicated if symptoms persist.

Routine bed rest has no proven benefit and is not recommended, although patients may limit strenuous activity. Sexual abstinence is often advised, but evidence that it influences miscarriage risk is limited.

Progesterone Therapy

The 2018 Cochrane review (including PRISM and PROMISE trials) suggests that vaginal micronized progesterone modestly increases live birth rates in women with threatened miscarriage, particularly in those with a history of prior pregnancy losses, while its routine use in first-time threatened miscarriage without previous losses remains debated.

Other Medications

Treatment options beyond progesterone that may be considered in selected cases:

• Analgesics: Paracetamol (choice for pain); NSAIDs generally avoided in early pregnancy
• Tranexamic acid: Small studies suggest benefit in controlling bleeding and resolving SCH; not routinely guideline-endorsed
• Alpha-lipoic acid: May reduce bleeding, pain, and hematoma size when added to progesterone (7–12 weeks); evidence limited to small non-blinded studies
• Antibiotics: Not routinely indicated; safer agents (penicillins, cephalosporins) only for confirmed genital or UTI
• Hydroxychloroquine: In APS with RPL not responding to aspirin + LMWH — improves live birth rates
• Low-dose aspirin + LMWH: Standard in APS or inherited thrombophilia with prior pregnancy loss
• Corticosteroids: Reserved for active autoimmune disease; not for threatened miscarriage alone
• hCG: Not recommended as standard therapy; Cochrane review does not support routine use
• Thyroxine: Only for documented hypothyroidism
• IVIG: Not routine; reserved for selected RPL cases in specialized settings

Special Considerations

Threatened Abortion in IVF Pregnancies

In IVF pregnancies, diagnostic evaluation is similar but monitoring is generally more intensive because of higher risks of miscarriage, multiple gestation, placental complications, and preterm birth. Earlier and more frequent ultrasound assessments, including SCH surveillance, are recommended. Early cervical length assessment (around 14 weeks) and closer monitoring for preterm birth may be required.

Prevention of Alloimmunization

Alloimmunization in threatened miscarriage is prevented by timely administration of anti-D immunoglobulin to unsensitized RhD-negative women:

• Minimum 250 IU before 20 weeks
• 500 IU at or beyond 20 weeks
• Ideally within 72 hours of bleeding episode (some benefit up to 10–13 days)

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