Threatened Miscarriage

Threatened miscarriage describes vaginal bleeding and cramping during early pregnancy that may—or may not—lead to pregnancy loss. While these symptoms can be frightening, many pregnancies continue successfully, with about 60% reaching full term despite early bleeding.

Table of contents

• What is a Threatened Miscarriage?
• Symptoms
• Causes and Risk Factors
• How Healthcare Providers Diagnose It
• Treatment and Management
• Outlook and Prognosis
• Caring for Yourself at Home
• When to Seek Emergency Help

threatened abortion, threatened early pregnancy loss

What is a Threatened Miscarriage?

A threatened miscarriage (also called a “threatened abortion” or “threatened early pregnancy loss”) describes a pregnancy that could possibly end in miscarriage due to mild vaginal bleeding with or without abdominal pain or cramping. The bleeding tends to stay light and cramping remains mild, sometimes lasting several days or weeks^[1].

Threatened miscarriages occur in the first half of pregnancy—up to 20 weeks—but most commonly during the first trimester (the first 13 weeks) of pregnancy^[1][2]. A key feature that distinguishes a threatened miscarriage from an actual miscarriage is that the cervical os (the opening of the cervix) remains closed, there is no passage of pregnancy tissue, and the fetus or embryo remains viable^[2].

It’s important to understand that experiencing vaginal bleeding or mild cramping during pregnancy doesn’t necessarily mean there’s a problem with the pregnancy or that miscarriage will happen. In many cases, you’ll go on to have a healthy pregnancy. These symptoms mainly tell your provider that further monitoring may be necessary^[1].

Threatened miscarriage may occur in about 15% to 20% of all pregnancies before 20 weeks^[1]. Approximately 25% of pregnancies have some degree of vaginal bleeding during the first trimester, and approximately half of these patients progress to early pregnancy loss^[2].

Symptoms

A threatened miscarriage typically includes one or both of the following symptoms^[1]:

• Vaginal bleeding (anything more than light spotting). The bleeding is mild and may include passing small clots or tissue-like material. The bleeding during a threatened miscarriage is typically mild to moderate; heavier bleeding that is more than typical menstrual flow is associated with an increased risk of pregnancy loss^[2].
• Abdominal cramps. The pain is typically dull, not sharp or intense. However, it can progress to constant, severe pain. Intermittent cramping, suprapubic pain, pelvic pressure, or lower back pain are also common^[1][2].

If you think or know you’re pregnant and have any symptoms of threatened miscarriage, contact your pregnancy care provider right away. Other conditions can cause vaginal bleeding and pelvic pain, so it’s best to discuss your symptoms with a healthcare professional so they can figure out what’s going on^[1].

A threatened miscarriage can last several days or several weeks. The exact timing and symptoms vary from person to person^[1].

Causes and Risk Factors

There isn’t one cause of a threatened miscarriage. Some factors that play a role in a person experiencing a miscarriage include^[1]:

• Chromosomal problems with the fetus
• Previously having a miscarriage
• Alcohol or drug use or exposure to chemicals early in the pregnancy
• Having obesity
• Being older than 40 during pregnancy
• Smoking cigarettes or vaping
• Problems with the placenta
• Trauma or injury
• Vaginal or uterine infections

It’s important to understand that in early pregnancy, things such as stress, exercise, and sex do not cause miscarriage. You may be worried or upset about the possibility of losing your pregnancy, but do not blame yourself. If you do have a miscarriage, there was nothing you could have done to prevent it. A miscarriage usually means that the pregnancy is not developing normally^[3].

How Healthcare Providers Diagnose It

Your pregnancy care provider will ask you about your symptoms and go over your medical history. They may also^[1]:

• Perform a vaginal or pelvic ultrasound to check the fetus’s heartbeat
• Do a pelvic exam to check if your cervix is closed
• Order hormone blood tests

Evaluation of threatened miscarriage depends on the pregnancy’s gestational age. At early gestational ages, it is essential to establish the location of the pregnancy to rule out an ectopic pregnancy (a pregnancy that develops outside the uterus), which can also present with vaginal bleeding and lower abdominal pain. Once an intrauterine pregnancy has been established, the clinician must determine the viability of the pregnancy, which is accomplished through a pelvic examination and ultrasound. If fetal cardiac activity is not seen, serial ultrasound examinations may be required to differentiate an early viable pregnancy from a pregnancy loss^[2].

Sometimes, HCG (human chorionic gonadotropin), known as the “pregnancy hormone,” levels are checked. HCG increases steadily until about 11 weeks of pregnancy (sometimes doubling every few days). In general, if HCG levels decline over several days, prior to 11 weeks, a miscarriage is likely. But in the case of a threatened miscarriage, a person’s HCG levels may remain steady. If your HCG levels are low, your provider will recheck your levels every two to three days. It’s important to note that in healthy pregnancies, HCG levels drop after about 11 weeks^[1].

Treatment and Management

Typically, threatened miscarriages are managed expectantly with close clinical monitoring^[2]. Treatment usually involves watchful waiting^[1]. There is no treatment to stop a miscarriage^[3].

Research has shown that progestogens—medications that mimic the activity of progesterone—may be a treatment option for patients with threatened miscarriage. Progesterone has physiologic roles in maintaining pregnancy by inducing changes in the endometrium, suppressing uterine contractions, and modulating the maternal immune system. Studies have found that progestogens reduce the risk of miscarriage when compared with placebo in patients with threatened miscarriage. Use of progestogens poses no significant risks to mother or baby^[6].

When progestogens were used, women receiving any progestogen therapy had a lower risk of miscarriage than those receiving placebo, with one study showing that 10 women would need to be treated to prevent one miscarriage. Although progestogens decreased the risk of miscarriage overall, this was significant only with orally—not vaginally—administered therapies. Progestogens as an intervention did not cause any significant harms. Adverse effects of progestogens are usually mild and include breast tenderness, bloating, and headache^[6].

Outlook and Prognosis

Yes, many fetuses survive and the pregnancy continues. One study found that of the 25% of pregnant women that had some vaginal bleeding in the first 20 weeks of pregnancy, 60% of them continued with the pregnancy to term (37 weeks)^[1].

In most cases, the pregnancy continues and doesn’t end in miscarriage^[1]. In many cases, you’ll go on to have a healthy pregnancy^[1].

Caring for Yourself at Home

While experiencing a threatened miscarriage, you can take several steps to care for yourself^[3]:

• Take acetaminophen (Tylenol) for cramps. Read and follow all instructions on the label. Do not take two or more pain medicines at the same time unless the doctor or midwife told you to. Many pain medicines have acetaminophen, which is Tylenol. Too much acetaminophen can be harmful.
• Do not have sex until your doctor or midwife says it is okay.
• Get lots of rest over the next several days.
• You may do your normal activities if you feel well enough to do them. But do not do any heavy exercise until your doctor or midwife says it is okay.
• Eat a balanced diet that is high in iron and vitamin C. Foods rich in iron include red meat, shellfish, eggs, beans, and leafy green vegetables. Foods high in vitamin C include citrus fruits, tomatoes, and broccoli. Talk to your doctor or midwife about whether you need to take iron pills or a multivitamin.
• Do not drink alcohol or use tobacco or illegal drugs.
• Do not smoke. If you need help quitting, talk to your doctor or midwife about stop-smoking programs and medicines.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line if you are having problems. It’s also a good idea to know your test results and keep a list of the medicines you take^[3].

When to Seek Emergency Help

Call 911 anytime you think you may need emergency care. For example, call if^[3]:

• You passed out (lost consciousness)
• You feel you cannot stop from hurting yourself or someone else

Call your doctor, midwife, or nurse advice line now or seek immediate medical care if^[3]:

• You have severe vaginal bleeding
• You are dizzy or light-headed, or you feel like you may faint
• You have new or worse pain in your belly or pelvis
• You have a fever
• You have vaginal discharge that smells bad

Watch closely for changes in your health, and be sure to contact your doctor, midwife, or nurse advice line if you do not get better as expected^[3].