Threatened Abortion

Threatened abortion, also known as threatened miscarriage, refers to vaginal bleeding that occurs before 20 weeks of gestation in a woman with a confirmed viable intrauterine pregnancy and a closed cervix. Some guidelines extend this cut-off to 24 weeks. While experiencing bleeding in early pregnancy can be concerning, it's important to know that approximately 50-70% of pregnancies with threatened abortion will continue to term, especially if a fetal heartbeat has been confirmed on ultrasound. However, it can also be a sign that a miscarriage may occur. If the pregnancy continues, women who experienced a threatened abortion may have an increased risk for certain complications later in pregnancy, such as preterm birth or placental abruption. It is crucial to seek medical evaluation promptly if you experience any vaginal bleeding during pregnancy to determine the cause and ensure appropriate care.

Symptoms

Vaginal bleeding or spotting (can be brown, pink, or red)
Mild lower abdominal cramping or aching
Low back pain
Passage of small blood clots
Heavy vaginal bleeding (soaking through one or more sanitary pads per hour) - Emergency symptom
Severe, persistent abdominal or pelvic pain (especially if one-sided) - Emergency symptom
Passage of fetal tissue (grayish or pinkish material) - Emergency symptom
Dizziness, lightheadedness, fainting, racing heart (symptoms of hemodynamic instability) - Emergency symptom
Fever or chills (may indicate infection) - Emergency symptom
Shoulder tip pain (can be a sign of a ruptured ectopic pregnancy) - Emergency symptom

Causes & Risk Factors

Often, the exact cause of bleeding is not identified.
Implantation bleeding (when the fertilized egg attaches to the uterine lining)
Subchorionic hematoma/hemorrhage (a collection of blood between the chorionic membrane and the uterine wall)
Cervical/vaginal/uterine pathology (non-pregnancy related causes such as cervical polyps, cervical ectropion, or vaginal trauma)
Infections (cervicitis or vaginitis)
In a significant number of cases, a specific cause for the bleeding is not found and is considered idiopathic.
Advanced maternal age (>35 years)
History of previous miscarriage
Uterine abnormalities (e.g., fibroids, congenital anomalies like septate uterus)
Chronic maternal diseases (e.g., poorly controlled diabetes mellitus, thyroid disease, antiphospholipid syndrome, systemic lupus erythematosus)
Chromosomal abnormalities in either parent
Smoking
Excessive alcohol consumption
Illicit drug use (e.g., cocaine)
Obesity (BMI > 30)
Underweight (BMI < 18.5)
Very high caffeine intake (>200-300 mg/day)
Maternal stress (possible factor)
Certain infections (e.g., bacterial vaginosis, listeria, toxoplasmosis) (possible factor)
Subchorionic hematoma (possible factor)

Diagnosis

Detailed medical history, including last menstrual period (LMP) to determine gestational age, characteristics of bleeding, presence and severity of pain, and obstetric history.
Physical examination, including abdominal examination, speculum examination to visualize the cervix and assess bleeding, and bimanual examination to assess uterine size and tenderness.
Serum beta-hCG (human chorionic gonadotropin) blood test to confirm pregnancy and assess viability with serial measurements.
Serum Progesterone blood test (low levels may suggest a nonviable pregnancy, high levels are reassuring; routine use is debated).
Blood type and Rh status to determine if Rho(D) immune globulin is needed for Rh-negative women.
Complete Blood Count (CBC) to check for anemia if bleeding is significant.
Transvaginal Ultrasound (TVS) to confirm pregnancy location, assess fetal viability by detecting a heartbeat, measure crown-rump length, and identify any uterine pathology.
Diagnostic criteria include vaginal bleeding before 20 (or 24) weeks of gestation, a closed internal cervical os, and ultrasound confirmation of a viable intrauterine pregnancy with a fetal heartbeat.
Differential diagnosis considers other conditions like ectopic pregnancy, molar pregnancy, other types of miscarriage, implantation bleeding, and local gynecological causes.

Treatment Options

Watchful waiting or expectant management, involving monitoring symptoms at home with clear instructions on when to seek further medical care.
Pelvic rest (avoiding sexual intercourse, tampons, and douching) is commonly recommended.
Reduced physical activity may be advised, but strict bed rest is not proven to improve outcomes and may increase the risk of blood clots.
Progesterone supplementation: Some guidelines, like NICE (UK), recommend vaginal micronized progesterone for women with an intrauterine pregnancy, vaginal bleeding, and a history of at least one previous miscarriage. Other guidelines, like ACOG (US), state that for threatened abortion, progesterone therapy has not been shown to be effective and is not routinely recommended, though it may be considered in women with a history of recurrent pregnancy loss.
Rho(D) Immune Globulin administered to Rh-negative women to prevent isoimmunization, especially after 12 weeks gestation or with heavy bleeding.
Emergency treatment for heavy bleeding and hemodynamic instability may include IV fluid resuscitation, blood transfusion, and urgent consultation with an obstetrician; surgical management (e.g., dilation and curettage) may be necessary.
Follow-up typically involves repeat ultrasound to re-assess fetal viability and serial beta-hCG testing if initial ultrasound is inconclusive.
Patient education on red flag symptoms is provided.
All women with bleeding in early pregnancy should be referred to an Early Pregnancy Assessment Unit (EPAU) or equivalent specialist for diagnosis and management.

Frequently Asked Questions

What is the exact cause of my bleeding?

The exact cause of bleeding in a threatened abortion is often not identified. Known causes can include implantation bleeding, a collection of blood near the placenta called a subchorionic hematoma, or non-pregnancy related issues like cervical polyps or infections. In many cases, a specific cause is not found.

Does this bleeding mean I am definitely going to miscarry?

No, experiencing bleeding does not mean you will definitely miscarry. Approximately 50-70% of pregnancies with threatened abortion will continue to term, especially if a fetal heartbeat has been confirmed on ultrasound. However, it does indicate an increased risk, and medical evaluation is important.

What are the chances that the pregnancy will continue normally?

The chances of the pregnancy continuing normally are good, especially if a fetal heartbeat is detected on ultrasound. The presence of a fetal heartbeat is the single most important prognostic factor, with miscarriage rates significantly lower (around 5-10%) after a heartbeat is seen. Overall, about 50-70% of pregnancies with threatened abortion continue to term.

Is there anything I did that caused this?

It is highly unlikely that you did anything to cause threatened abortion. Many causes are related to factors beyond your control, such as chromosomal abnormalities. While certain lifestyle factors like smoking or excessive alcohol use can increase risk, bleeding often occurs without a clear preventable cause.

Is strict bed rest necessary or helpful?

Strict bed rest is commonly advised, but there is little to no evidence that it improves outcomes for threatened abortion. In fact, prolonged bed rest may increase the risk of blood clots. Reduced physical activity may be advised, but your healthcare provider will give specific recommendations.

Can I continue to work and do my daily activities?

Your ability to continue work and daily activities will depend on your specific situation and your healthcare provider's advice. While strict bed rest is not generally recommended, reduced physical activity might be suggested. It's best to discuss your activities with your doctor.

When is it safe to have sex again?

Pelvic rest, which includes avoiding sexual intercourse, tampons, and douching, is commonly recommended to avoid stimulating the cervix or introducing infection. Your healthcare provider will advise you on when it is safe to resume sexual activity based on your condition and symptoms.

Will taking progesterone help save this pregnancy?

The evidence regarding progesterone supplementation for threatened abortion is evolving and recommendations vary. Some guidelines, like those in the UK (NICE), suggest offering vaginal progesterone to women with an intrauterine pregnancy, vaginal bleeding, and a history of at least one previous miscarriage. However, other guidelines, like ACOG in the US, state that for threatened abortion, progesterone therapy has not been shown to be effective and is not routinely recommended, though it may be considered in women with a history of recurrent pregnancy loss. Discuss this option with your doctor.

What are the side effects of progesterone?

The dossier does not specifically detail the side effects of progesterone. However, if prescribed, your healthcare provider will discuss potential side effects with you.

What symptoms should I watch for that would require me to go to the hospital?

You should go to the hospital immediately if you experience heavy vaginal bleeding (soaking through one or more sanitary pads per hour), severe or persistent abdominal/pelvic pain (especially if one-sided), passage of fetal tissue, symptoms of hemodynamic instability (dizziness, fainting, racing heart), fever or chills, or shoulder tip pain.

How long is this bleeding expected to last?

The dossier does not specify how long bleeding is expected to last. The duration can vary greatly among individuals. Your healthcare provider will monitor your symptoms and provide guidance based on your specific situation.

If the pregnancy continues, will the bleeding have harmed my baby?

If the pregnancy continues after a threatened abortion, the bleeding itself is not typically considered to have directly harmed the baby. However, women who experience threatened abortion and continue their pregnancy are at an increased risk for certain adverse pregnancy outcomes later on, such as preterm birth, low birth weight, or placental abruption. Your doctor will monitor you closely.

Do I need another ultrasound, and if so, when?

Yes, a repeat ultrasound is often needed to re-assess fetal viability and ensure the pregnancy is progressing as expected. Your healthcare provider will determine the appropriate timing for follow-up ultrasounds based on your initial findings and symptoms.

Why do you need to check my blood type?

Your blood type and Rh status are checked to determine if you are Rh-negative. If you are Rh-negative, you may need an injection of Rho(D) immune globulin to prevent your body from developing antibodies that could harm future pregnancies, especially after 12 weeks gestation or with heavy bleeding.

Is there anything I can do right now to stop the bleeding or prevent a miscarriage?

There is no specific action you can take immediately to stop the bleeding or prevent a miscarriage once it has started. The most important step is to seek prompt medical evaluation to determine the cause and receive appropriate care. Your doctor may recommend pelvic rest and reduced physical activity.

What is a subchorionic hematoma?

A subchorionic hematoma is a collection of blood that forms between the chorionic membrane (one of the fetal membranes) and the uterine wall. It is a known cause of bleeding in early pregnancy and can be identified with an ultrasound.

If my bleeding stops, does that mean everything is okay?

If your bleeding stops, it is a positive sign, but it does not automatically mean everything is okay. It is still important to follow up with your healthcare provider for any recommended ultrasounds or tests to confirm the continued viability and health of the pregnancy.

Does having cramps with the bleeding make a miscarriage more likely?

Mild lower abdominal cramping or aching can be a common symptom of threatened abortion. While severe, persistent pain can be a red flag, mild cramping alone does not definitively mean a miscarriage is more likely. The presence of a fetal heartbeat on ultrasound is a more significant prognostic factor.

Should I stop exercising completely?

Reduced physical activity may be advised, but there is little evidence that strict bed rest or completely stopping all activity improves outcomes. Discuss your exercise routine and any necessary modifications with your healthcare provider.

What is the follow-up plan from here?

The follow-up plan typically involves repeat ultrasounds to re-assess fetal viability, serial beta-hCG testing if initial ultrasound was inconclusive, and patient education on red flag symptoms. All women with bleeding in early pregnancy should be referred to an Early Pregnancy Assessment Unit or equivalent specialist for ongoing management.