Early Pregnancy Loss Workup

Updated: Nov 15, 2017
  • Author: Elizabeth E Puscheck, MD; Chief Editor: Richard Scott Lucidi, MD, FACOG  more...
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Workup

Laboratory Studies

Complete blood count (CBC) with differential

A CBC will help document the amount of blood loss and whether anemia is present. If the hemoglobin and hematocrit are very low and the patient is symptomatic then transfusions would be warranted. The CBC also will provide evidence regarding an infection, which, in the case of infection, would yield an elevated white blood cell count and a left shift on differential.

Beta-hCG

Beta-hCG is important to confirm the pregnancy and distinguish it from dysfunctional uterine bleeding or bleeding from another etiology. The hCG level is also important to help distinguish a complete abortion from a threatened abortion or ectopic pregnancy.

If the hCG level is above 1500-2000 mIU/mL, then transvaginal ultrasonography should detect a viable intrauterine pregnancy. A level over 3000 mIU/mL should enable one to visualize a viable intrauterine pregnancy by transabdominal ultrasonography. If the values are so elevated, the cervical canal is closed, and the patient's history is consistent with passing tissue (which a physician has confirmed), then an empty uterus on ultrasonography is consistent with a completed abortion. However, if the hCG level is elevated, no history of passing tissue is present, and the ultrasonography demonstrates an empty uterus, one must assume that an ectopic pregnancy is present until proven otherwise.

Low hCG levels (ie, < 200 mIU/mL) may make the diagnosis more difficult. Observation and monitoring the hCG levels every few days may be an option if the patient is stable and not complaining of pain. If these low hCG levels plateau and fall, the patient will likely miscarry or have a tubal abortion on her own. However, if the values rise, then follow-up ultrasonography is necessary to determine whether an intrauterine pregnancy or an ectopic pregnancy is present and subsequent appropriate management is necessary. The hCG level should rise at least 53% every 2 days during the early first trimester. [24]

Blood type and screen

Blood type and screen (possible crossmatch) is important to determine whether treatment with RhoGAM is appropriate. An Rh-negative woman should receive RhoGAM within 72 hours of miscarriage or ectopic pregnancy to avoid the possibility that the pregnancy has exposed the patient to a positive antigen. If the father of the baby is also Rh negative then the patient can forego the immunoglobulin therapy. It is also important in cases where transfusions are necessary.

Possible DIC profile

A DIC profile is necessary only in those cases with significant bleeding. The DIC profile usually consists of a platelet count, fibrinogen level, prothrombin time (PT), and activated partial prothrombin time (aPTT). When significant bleeding occurs and the patient is consuming these factors faster then she can make them, then the initiating event needs to be treated (ie, D&C, hysterectomy) and platelets, coagulation factors (usually administered in the form of fresh frozen plasma or cryoprecipitate), or fibrinogen in addition to packed red blood cells may need to be replaced when transfusing a patient. Whole blood may be transfused as another alternative.

Urinalysis

Urinalysis is important to rule out a urinary tract infection. Pregnant women are prone to urinary tract infections due to the progesterone effect on the smooth muscle of the ureters, which causes mild physiologic hydroureters. A cystitis or renal stone also could be present with bleeding but from a urinary source.

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Imaging Studies

Ultrasonography of the pelvis using a vaginal probe should be performed to rule out an ectopic pregnancy, retained products of conception, hematometra, or other etiologies. Once the discriminatory level is passed, the ultrasound is fairly reliable as long as it is taken within the clinical scenario.

Guidelines for assessing prenatal viability

In October 2013, the Society of Radiologists in Ultrasound published new guidelines on using ultrasonography to assess prenatal viability. [25, 26] The guidelines are designed to help avoid the possibility of physicians causing inadvertent harm to a potentially normal pregnancy.

Diagnostic criteria for nonviability include the following:

  • A crown–rump length of ≥7 mm and no heartbeat

  • A mean sac diameter of ≥25 mm and the absence of an embryo

  • The absence of an embryo with heartbeat ≥2 weeks following a scan that showed a gestational sac with no yolk sac

  • The absence of an embryo with heartbeat ≥11 days following a scan that showed a gestational sac with a yolk sac

Findings that are suspicious for, but not diagnostic of, a pregnancy failure include the following:

  • A crown–rump length of < 7 mm and no heartbeat

  • A mean sac diameter of 16–24 mm and the absence of an embryo

  • The absence of an embryo with heartbeat 7–13 days following a scan that showed a gestational sac with no yolk sac

  • The absence of an embryo with heartbeat 7–10 days following a scan that showed a gestational sac with a yolk sac

  • The absence of an embryo ≥6 wk after the last menstrual period

  • An empty amnion

  • An enlarged yolk sac (>7 mm)

  • A small gestational sac in relation to the embryo size (< 5 mm difference between the mean sac diameter and the crown–rump length)

Presence of one or more of these findings should prompt further investigation into the pregnancy's viability.

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Procedures

If the diagnosis truly is a complete abortion, then no further procedures are needed.

If the diagnosis is unclear and there is fluid in the cul de sac, then a culdocentesis can be performed. This procedure is one where a needle with 10-20 mL syringe attached is placed into the posterior cul de sac through the vagina and the fluid is aspirated. If the fluid consists of nonclotting blood, then a ruptured ectopic pregnancy must be considered. This technique is not used often.

Alternatively, if the diagnosis is unclear, but normal early pregnancy has been excluded, a diagnostic D&C may be performed. In this situation, the specimen is sent for pathologic evaluation and, if chorionic villi are found, then an intrauterine pregnancy demise is confirmed. No further treatment is needed beyond the suction D&C. However, if no chorionic villi are found, then one needs to presume that an ectopic pregnancy is present and initiate appropriate treatment.

Pathology results from specimen sent from an early pregnancy (either from D&C for incomplete abortion or from ectopic pregnancy) should reveal chorionic villi.

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