A pelvic exam is mandatory to determine the type of abortion. Determining factors include the amount and site of bleeding, whether the cervix is dilated, and whether fetal tissue has passed. In a threatened abortion, the vaginal exam may reveal a closed cervical os with no tissue. There is usually no cervical motion tenderness. In rare cases, the pelvic exam will reveal uterine and bilateral adnexal tenderness. It is important to note that in a threatened abortion there is no passage of tissue and the cervical os is, by definition, closed. These observations differentiate the condition from an inevitable or incomplete abortion. Women with a threatened abortion usually have stable vital signs, but if hypovolemia is present, one should suspect bleeding or sepsis. The abdomen in most cases is non-tender and soft. If it is confirmed that there is no viable fetus, a discussion concerning expectant management or induction of abortion should occur with the patient. The method of inducing abortion is either surgical with a suction dilation and curettage or medical with a medication like misoprostol. 

The diagnosis is made by history, physical exam, measurement of beta-human chorionic gonadotropin (beta-hCG), and an ultrasound. 

A thorough history should be obtained including pregnancy history, medical history, and history of present illness. History of present illness should include when and how symptoms/bleeding began, modifying factors, any treatments trialed up to the point of evaluation, and helping the patient to describe and quantify the bleeding. 

Transvaginal ultrasound may be used to locate the pregnancy and determine if the fetus is viable. The ultrasound can also help rule out ectopic pregnancy and to evaluate for retained products of conception. A yolk sac is typically seen at 36 days, and a heartbeat is seen on ultrasound at approximately 45 days after the last menstruation.

A beta-hCG level of 1500 lU/mL to 2000 lU/mL is associated with a gestational sac on ultrasound. Beta-hCG doubles in 48 hours in 85% of intrauterine pregnancies. Beta-hCG is usually detectable the first nine to 11 days following ovulation and reaches 200 IU/mL at the expected time of menses.

Rh factor will also determine if Rhogam should be administered to prevent hemolytic disease of the newborn in this pregnancy and subsequent pregnancies.

Hemoglobin and hematocrit levels help monitor the degree of blood loss. 

A urinalysis can also be obtained. Urinary tract infection (UTI) has been associated with signs and symptoms of threatened abortion.

During the pelvic exam, suction or cotton swabs may be needed to remove blood and products of conception to allow for better visualization of the cervix. Ringed forceps can also be used to remove tissue that may be protruding from the cervical os. All tissue must be examined to determine if it is a clot or products of conception. Evidence of products of conception protruding from the cervix or within the vagina changes the diagnosis from a threatened abortion to a complete or incomplete abortion. Evaluation of the amount of bleeding/blood loss should be performed through a thorough history, as well as during the pelvic examination. 

Alloimmunization prevention by the administration of Rh(D) immunoglobulin should be considered for patients who have vaginal bleeding in the setting of pregnancy in a patient who is Rh-.  It has been determined that a 50 mcg dose of immunoglobulin is effective at alloimmunization prevention up to and through the 12th week of gestation, however, it is considered acceptable to give the standard 300 mcg dose due to availability or provider preference.

Patients with a threatened abortion should be managed expectantly without any medical or surgical interventions. However, patients should be given strict return precautions concerning excessive vaginal bleeding, abdominal pain, or fever and patients should be educated on the importance of follow-up. Analgesia can be provided to help relieve discomfort from cramping. NSAIDs should be avoided in the setting of a threatened abortion, as the pregnancy may continue to progress to viability. Follow-up is recommended with serial transvaginal ultrasounds until a viable intrauterine pregnancy is confirmed or until progression to an inevitable, incomplete, or complete abortion occurs.  Clinicians can consider serial quantitative beta hCG testing as recommended for a pregnancy of unknown origin to continue to monitor for the viability of the pregnancy, especially in the setting where an intrauterine pregnancy with cardiac activity has not been confirmed by ultrasound.  In these cases, it is possible that the pregnancy has not reached the gestational age by which cardiac activity would be expected on ultrasound or it is possible that the pregnancy will not be viable.  The patient should be counseled about the possibility of spontaneous abortion of the pregnancy, as well as the possibility that the pregnancy may continue to progress towards viability.  Several trials have shown that progesterone supplementation does not improve outcomes for patients with threatened abortion and progesterone is not currently recommended as treatment or prevention for patients with threatened abortion.  Bedrest and other activity restrictions have not been found to be efficacious in the prevention of a threatened abortion progressing to spontaneous abortion and have been shown to increase the risk of other complications including deep vein thrombosis and/or pulmonary embolism and therefore should not be recommended.  Some providers do prefer to advise patients to avoid strenuous activities and to maintain pelvic rest at least until the cessation of vaginal bleeding. Clinicians should recommend that patients start or continue to take prenatal vitamins with folic acid supplementation. [8][9][10][11]

Clinicians should consider several differential diagnoses when encountering vaginal bleeding in the setting of pregnancy. Vulvar, vaginal, cervical trauma should be ruled out during a pelvic examination.  Cervical friability can lead to vaginal bleeding which can be caused by cervicitis from an infection or due to premalignant or malignant changes on the cervix. Clinical judgment should determine whether or not the patient should undergo a Pap smear and/or cultures for infection at the time of examination. Other types of abortion should be considered including elective, inevitable, incomplete, complete, septic, and missed abortion. 

Studies have shown that about 20% of women experience vaginal bleeding before 20 weeks of pregnancy. Furthermore, about 50% of those patients who experience a threatened abortion progress to a pregnancy loss. Studies have shown that there may be an increased risk of adverse outcomes later in pregnancy if there was vaginal bleeding during the first trimester of that pregnancy. For example, there may be a greater risk of placenta previa, placental abruption, necessitation for manual removal of the placenta after delivery, cesarean delivery, preterm premature ruptured membranes, preterm birth, low-birthweight infant, fetal-growth restriction, and fetal or neonatal death. 

• Pregnancy loss (progression to inevitable, incomplete, complete, missed abortion)
• Heavy bleeding
• Retained products of conception
• Endometritis
• Septic abortion 
• Complications later in pregnancy as discussed in "Prognosis" 

Patients with recurrent pregnancy loss or recurrent bleeding during pregnancy should be offered evaluation by a reproductive endocrinology and infertility specialist and/or by a maternal-fetal medicine specialist. If a patient is determined to have a coagulopathy, a hematology consult should be considered. 

Patient education should be provided as both verbal and written explanations and instructions. It should be explained to the patient that it is possible her pregnancy will continue and it is also possible that she will undergo a miscarriage. The patient needs to understand that the vast majority of miscarriages are not preventable and that she is not at fault for the loss of the pregnancy if a loss does occur. Providers should explain to the patient that mild to moderate bleeding and cramping can be expected, but uncontrolled pain or heavy bleeding should be evaluated by an obstetric care provider or in the emergency department. Many providers explain that saturating more than 1-2 pads per hour for 2 hours is considered to be heavy bleeding and should be promptly evaluated. Patients can be instructed to take acetaminophen as directed for pain relief. Patients should avoid ibuprofen for pain control during a threatened abortion as it is contraindicated in pregnancy and the patient's pregnancy may progress to viability. Patients who undergo threatened abortion should be evaluated for mood disorders including depression and anxiety. Especially if a threatened abortion proceeds to pregnancy loss, the patient should be allowed to grieve as appropriate for each individual and should be offered grief counseling.

Most patients with a threatened abortion can be observed from home with close follow-up. Repeat ultrasounds and beta-hCG levels will help to determine progression to a viable pregnancy or to an inevitable, complete, incomplete, or missed abortion. Patients with increased vaginal bleeding require evaluation for hemorrhagic anemia and may be candidates for a blood transfusion or pregnancy evacuation. 

The diagnosis and management of a threatened abortion involve an interprofessional team that can include an emergency department physician, obstetrician, radiologist, midlevel providers, and nursing staff.  For patients to be safely monitored expectantly, good communication between clinicians and the patient is key. All members of the care team need to be on the same page regarding the possibility of pregnancy loss and the importance of return precautions.