Clinical Concept: Managing first trimester vaginal bleeding in the ED

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Written by: Priyanka Sista, MD (NUEM PGY-2) Edited by: Spencer Lang, MD, (NUEM PGY-4) Expert
Commentary by
:  Natasha Wheaton, MD


Vaginal bleeding in a pregnant patient occurs frequently (20-40% of all 1st-trimester pregnancies) and these patients present to the Emergency Department often. Patients in their 1st trimester (prior to 12 weeks gestational age) may not have initiated prenatal care and may not have a definitive intrauterine pregnancy (IUP). In fact, they may not be aware that they are pregnant at all. In patients with 1st trimester bleeding, consideration of ectopic pregnancy should be a priority for the emergency physician. Ectopic pregnancies, while rare, are responsible for the greatest morbidity and mortality in early pregnancy. When ectopic pregnancies are diagnosed - or even strongly suspected - management should involve consultation with an OB/GYN, either for emergent surgical management or medical management. The vast majority of 1st trimester bleeding, however, falls into a spectrum of “it’s too early to tell.” The differential of early bleeding with an undetermined pregnancy location ranges from completed abortions to benign subchorionic hemorrhages, with multiple options in between. This degree of uncertainty is often emotionally difficult to absorb for both patients and clinicians. Having a thorough management approach to 1st trimester bleeding, clearly communicating the uncertainty in prognosis, and providing accurate anticipatory guidance can better protect patients, ensure appropriate follow-up, and may even offer reassurance.  

Diagnostic algorithm for vaginal bleeding in early pregnancy (< 12 weeks gestation age)

1.     Is the patient hemodynamically stable?

If not, you should begin resuscitation and consult gynecology early for strong suspicion of ectopic pregnancy. Ensure the patient has 2 large-bore IVs, give crystalloids, check a hemoglobin, type and cross-match blood, and perform a FAST exam to look for free fluid in the abdomen. If the patient is actively hemorrhaging and you cannot wait for a type and cross, transfuse O-negative blood. Administer RhoGam (see below). If you suspect the patient is septic from a septic abortion, give antibiotics (see below).  If you suspect the patient is headed to the OR emergently, order the appropriate pre-op labs.

Before continuing with the rest of the diagnostic algorithm, all pregnant vaginal bleeders will typically receive the following, unless there is rationale not to do so: urine pregnancy test, serum beta-hCG, type and screen, a CBC, and a transvaginal ultrasound.

2.     Confirm an IUP with transvaginal ultrasound (TVUS).

For all intents and purposes, confirmation of an intrauterine pregnancy effectively rules out ectopic pregnancy (with rare exceptions, see heterotopic pregnancy, below).

How do you confirm an IUP? 

With ultrasound:

  • Visualize a gestational sac (dark anechoic area) within the endometrial cavity. Typically visualized around 4-5 weeks gestational age.

  • Visualize a yolk sac (concentric circle, around 5.5 weeks) or fetal pole (6.5 weeks) within the gestational sac.

Measuring the Yolk Sac, a concentric circle within the gestational sac

Ectopic pregnancies secrete hormones that can cause changes in the endometrial lining, which may look like a gestational sac, called a “pseudogestational sac of ectopic pregnancy.” Therefore, an IUP is confirmed when the yolk sac or fetal pole is visualized within the gestational sac.





A and B: Endovaginal views showing an intrauterine pregnancy. The gestational sac (blue) is located within the endometrial stripe of the uterus (yellow) and contains a fetal pole (purple).

3.     What if the TVUS is indeterminate and you cannot confirm an IUP?

If you cannot confirm an IUP by TVUS, then you cannot effectively rule out an ectopic pregnancy – this is deemed a pregnancy of unknown location (PUL). This means the patient may have an early presentation of ectopic pregnancy, may be too early in their pregnancy to visualize an IUP, or may have a nonviable IUP.

With an indeterminate TVUS, consider the serum beta-hCG level. The discriminatory zone is the level of beta-hCG above which one should be able to identify an IUP by ultrasound (for TVUS, the discriminatory zone 1000-1500 mIU/mL; for transabdominal ultrasound, it is 4000-6500 mIU/mL).

  • When patients have beta-hCG levels above the discriminatory zone, presume an ectopic pregnancy until proven otherwise and consult OB/GYN.

  • When patients have beta-hCG levels below the discriminatory zone and an indeterminate TVUS, you still cannot rule out ectopic pregnancy. Patients have presented with ruptured ectopic pregnancies with beta-hCG levels well below the discriminatory zone. If clinical suspicion is high or you identify free fluid in the pelvis, presume ectopic pregnancy and consult gynecology, regardless of beta-hCG level. If there is no free fluid identified and the patient remains stable and well-appearing, they will need close follow-up and monitoring in 48 hours to re-check serum-hCG levels. In normal viable pregnancies, the serum hCG is expected to roughly double every 48 hours in the 1st trimester. In ectopic or nonviable pregnancies, the serum hCG may seem normal, rise less quickly than expected, or in the case of spontaneous abortion, may plateau or fall. It is the ED physician’s responsibility to ensure this patient has good follow-up in 48 hours for serum beta-hCG recheck, as well as to give strict return precautions for signs of a ruptured ectopic pregnancy.

(A word on heterotopic pregnancy: Heterotropic pregnancy refers to pregnancies at two different implantation sites, most typically a combination of an IUP and an ectopic pregnancy. While it was and is quite rare,  (1 per p 30,000 pregnancies), the incidence is increasing with the use of assisted reproduction techniques (ART). An estimated 1.5 per 1000 ART pregnancies are heterotopic. Therefore, patients who used  ART should get a formal ultrasound in the ED, and all women should have close follow-up. )

4.     Is the cervix open or closed? Is the pregnancy viable or nonviable?

When an IUP is confirmed, a patient with 1st trimester vaginal bleeding may be presenting with a spontaneous abortion. Classification of spontaneous abortion is provided in the table below, and requires a pelvic exam to determine whether the cervix is open or closed.

The majority of patients who present to the ED will be diagnosed with “threatened abortion,” which includes bleeding or cramping, a viable pregnancy, and a closed cervix. Approximately 50% of these patients will proceed to have a miscarriage.

Most spontaneous abortions in the 1st trimester will progress to completion without complications. If they do not progress, the patient may require medical or surgical intervention to remove all POC. Septic abortions may occur if infection complicates the pregnancy loss.

What makes a pregnancy nonviable? The following ultrasound findings:  

  • Crown-rump length of > or = 7 mm and no heartbeat.

  • Mean sac diameter > or = 25 mm and no embryo

  • Absence of embryo w/ heartbeat > or = 2 weeks after a scan that showed a gestational sac without a yolk sac.

  • Absence of embryo with heartbeat > or = 11 days after a scan that showed a gestational sac with a yolk sac

Rh immunization

All Rh negative mothers should get 50 mcgs of RhoGam in the 1st trimester when they are less than 12 weeks gestation, based on expert clinical opinion.  This will be good for any subsequent bleeding that occurs in the following 12 weeks. At some institutions, patients get the full dose RhoGam (300 mcgs) regardless of gestational age, but this is only recommended for patients beyond 12 weeks.

Counseling, FAQs, and Anticipatory Guidance

Given that implications of 1st trimester bleeding are often determined with time, it is critically important to establish appropriate follow-up plans for patients. Providing a safe, reassuring presence with clear information and clear instructions in the midst of uncertainty may help ensure appropriate follow-up. Here are some tips to keep in mind:

  • Ask all patients “Is this a desired pregnancy?” Do not make assumptions or judgments about the nuances of a patient’s situation.

  • Patients may mourn and grieve pregnancy loss similar to the loss of a child or family member. This can be true even for undesired pregnancies. We may forget that we need the same level of kindness for patients experiencing a spontaneous abortion as we do for the mother of a patient with fatal GSW injuries.

  • While we use the term “abortion” in a medical context, for most people it is fraught with political and emotional complexity. Please explain the medical term so that a patient does not see the word for the first time as a discharge diagnosis.

Pregnancy of Unknown Location Discharge Instructions:

1.     Patients MUST follow-up in 48 hours to re-check a serum beta-hCG level.

What will happen at that visit?  If there is an inappropriate rise in beta-hCG level, there is concern for ectopic or nonviable pregnancy. When the beta-hCG level is above the discriminatory zone, a repeat TVUS will be obtained to confirm a viable IUP. If there is no IUP determined, there is concern for ectopic or nonviable pregnancy. Gynecology will help in management decisions at that point: they may choose to monitor the hCG levels, or they may give you medications or consider operative management to help facilitate the nonviable pregnancy to its completion.

What will happen if you don’t follow-up? There is risk of the pregnancy growing in a dangerous location outside the uterus, rupturing, and causing life-threatening bleeding into the abdomen. There is also the risk of missed, incomplete, or septic abortions, which can be life-threatening if allowed to progress. Intervention is sometimes needed to help the body terminate an ectopic or nonviable pregnancy to avoid the possibility of life-threatening hemorrhage and/or infection. 

What does a nonviable pregnancy mean? It means an abnormal pregnancy that will not be carried to completion due to some factors that make it incompatible with progression. (See above for diagnostic definitions)


2.     Use Tylenol for abdominal cramping if needed. Stay well hydrated. Have 2 weeks of pelvic rest (nothing in the vagina for two weeks). There is no evidence to prove that pelvic rest improves outcomes or reduces the likelihood of spontaneous abortion. Theoretically, sexual activity may trigger ectopic rupture but there is no evidence to suggest this. However, pelvic rest is widely recommended to eliminate any possible feelings of guilt that patients may have regarding being responsible for a spontaneous abortion. 

Patients with known open cervical os may continue to bleed significantly. Those with closed cervical os may develop an open os in the coming hours/days. Warn the patient that they may pass blood clots or products of conception. If a patient is concerned they passed products of conception, ask them to retrieve it and bring to their doctor’s or to the ED. Given them gloves and a specimen cup. If a patient is bleeding more than 2 pads an hour for more than 2 hours in a row, tell them to return to the ED.


3.     You must immediately return to the emergency department if you have:

  • Increased or persistent abdominal pain

  • Heavy vaginal bleeding (more than 2 pads an hour for 2 consecutive hours)

  • Weakness, dizziness, lightheadedness.

FAQs, and answers to have in your back pocket:

1.     How common is 1st trimester bleeding? 25-33% of pregnancies will have 1st trimester bleeding.

2.     What does this mean regarding the future of this pregnancy? Approximately half of patients with 1st trimester bleeding will have a subsequent spontaneous miscarriage.

3.     Does this mean I’m miscarrying? Unless the patient has an open os or a documented nonviable pregnancy, it is difficult to tell in the ED. It’s okay to say “I don’t yet know,” and “time will tell, which is why follow-up is important.”

4.     What do I need to watch out for?  What activities can I resume or not resume? With any vaginal bleeding in pregnancy, suggest pelvic rest for 2 weeks. Avoid ibuprofen; take Tylenol for pain. Watch out for the ectopic precautions listed above. Otherwise, if you feel up for doing something, it is OK to do it.

5.     How much bleeding is too much? More than 2 pads an hour for more than 2 hours is too much bleeding.

6.     Why did this happen? Miscarriages are common, occurring in 25-33% of pregnancies. More than half the time, miscarriages occur due to an intrinsic genetic or chromosomal abnormality that occurs during fertilization, rather than due to some inheritable trait, or extrinsic factor. For patients who have recurrent miscarriages, there may be structural or extrinsic causes for pregnancy termination, which warrants workup by the gynecologist.

7.     Did I miscarry because I had sex / took Tylenol / went on a run / had a  glass of wine before I realized I was pregnant? Reassure the patients that miscarriage is common and that there’s nothing they did to cause this. Miscarriage happens in up to one-third of all pregnancies.  

8.     Who gets genetic testing and has tissue pathology testing? For a first-time miscarriage, no genetic testing or tissue pathology is warranted. For subsequent miscarriages, products of conception can be sent to tissue pathology, and extrinsic causes of spontaneous abortion can be evaluated by a gynecologist.

9.     What does a miscarriage mean for future pregnancies? Most patients will subsequently have normal future pregnancies., but it is true that having a miscarriage increases the chance of subsequent miscarriages slightly.

10.  When can I start trying to get pregnant again? Patients can ovulate and become pregnant as soon as 2 weeks after miscarriage. Most gynecologists recommend waiting one menstrual cycle so that it is easier to calculate the due date of the next pregnancy, but there is no medical reason to wait to begin trying again. If patients do not want to get pregnant again right away, be sure to use birth control.

11.  Reassure patients that if they are concerned about anything at all, or there is any change in their health, there should be a low threshold for calling a gynecologist on-call or returning to the ED for re-evaluation.

Expert Commentary

This is a comprehensive and well written entry on a very common complaint seen in the ED. Though the basic principles of early pregnancy related vaginal bleeding are relatively straightforward; confirm an IUP, administer Rhogam if indicated and provide anticipatory guidance, there are several nuances that bear mentioning and will improve patient care as well as patient experience.

As stated in the blog, after determining hemodynamic stability, the next step is usually to ensure the pregnancy is developing in the correct anatomic location (ie “find the IUP!”). However, there are some nuances regarding transvaginal ultrasound in early pregnancy. First, it is worth emphasizing that ectopics can exist at truly ANY hcg level (fine, fine except at zero) so don’t let anyone convince you to skip the ultrasound because “the beta is too low”. In fact, in a retrospective study of 730 women seen in the ED with early pregnancy bleeding, a β-HCG of <1,500 mIU/mL more than doubled their chances of having an ectopic pregnancy (Acad. Emerg. Med. 2003;10:119-26). Another study found that 40% of ruptured ectopics had β-HCG < 1,000 mIU/mL, suggesting that those women with ectopics and lower quants may actually have poorer outcomes.

If you are doing your own transvaginal ultrasound (or even when reviewing those done by radiology), don’t confuse a pseudogestational sac for a true gestational sac. Pseudosacs are seen in up to 20% of ectopic pregnancies (Radiology. 1979;133:451–454) and are irregular, heterogeneous and lack a yolk sac. When you are concerned for a pseudosac, be especially vigilant for secondary signs of ectopic including free fluid in Douglas’ pouch posterior to the uterus or abnormal adnexal masses. Finally, remember that while the vast majority of ectopics are tubal, there are multiple other locations where ectopics can implant some of which are particularly difficult to detect on ultrasound. Interstitial ectopics are particularly difficult as they appear to be in the uterus but are in fact within the myometrial tissue rather than in the uterine cavity. Though the exact measurements remain controversial, most agree that a measurement less than 8 mm of myometrium surrounding the gestational sac is abnormal (

Though there is some data suggesting that pelvic exams in the ED often don’t alter management, I still advocate for a pelvic exam in these patients for several reasons. First, it helps quantify the amount of bleeding. There is some data that those with heavy bleeding are more likely to miscarry than those with lighter bleeding (Hasan et al, Obstet Gynecol. 2005 Nov;106(5 Pt 1):993-9). If there are products present at the cervical os, delivery of those with ring forceps may shorten the patients pain and bleeding. An evaluation of the cervix may rule out other causes of bleeding including STIs or trauma. Remember that domestic violence levels peak during pregnancy so be on the lookout for it, GU trauma can be a sign! Finally, a bimanual exam can help risk stratify the patient and aid in your counseling. If the cervix is dilated, that is a nonviable pregnancy and an “inevitable abortion”. The counseling for that woman is significantly different than counseling for one with mild vaginal spotting and a closed cervical os.  

A few notes on the practicalities of performing this physical exam. First, a pelvic can be particularly uncomfortable when pregnant so please take your time and warn the woman before you start. Be ready to collect tissue so you’re not scrambling if you find tissue unexpectedly. Grab ring forceps, a sterile collection cup as well as Fox swabs and an extra Chux to cover your used instruments. If you collect tissue, it may be worth sending to the lab for chromosomal analysis though this is really only indicated in recurrent pregnancy loss.

A word on ART patients. First, know that their dates are exact so if you don’t see a yolk sac when expected (5.5 weeks) or a heartbeat when expected (just under 6 weeks) it’s probably not a viable pregnancy. Also, be highly suspicious of hetero-ectopics in these patients! Their risk is upwards of 2-5% (Fertil Res Pract. 2015; 1: 15.) so don’t be too comforted by a TVUS showing an IUP. I would advocate for early involvement of their REI physicians to ensure close and appropriate early follow up.

As we wrap up, let’s talk numbers. While there is some data showing a 50% miscarriage rate for all-comers to the ED with vaginal bleeding in early pregnancy (< 12 weeks), this number changes significantly depending on what we find in the ED. With a closed cervix, mild bleeding and a TVUS showing a heartbeat, the risk drops to closer to 10%. The heavier the bleeding, the higher the risk. Finally, a subchorionic hemorrhage on ultrasound does increase the risk of miscarriage to closer to 25% though the risk also depends on the size of the hemorrhage (J Obstet Gynaecol. 2006 Nov;26(8):782-4.)

So, what about follow up? As the blog notes, if we have yet to confirm an IUP, these patients need 48-hour follow up for a repeat β-HCG and consideration of an ultrasound. But what if we did find an IUP? If the woman does go on to miscarry, does she need to see a provider? And how long can she bleed before Ob/Gyn would consider offering her surgical intervention (ie D&C) if desired by the patient? Does she have to have a D&C?

In general, I counsel women with documented IUPs that if they begin to bleed significantly more, pass clots or tissue and go on to have more intense cramping they are likely to be experiencing a miscarriage. They do not necessarily need to return to care as many women prefer to miscarry in the comfort of their own homes, as long as there is not excessive bleeding, severe abdominal pain, fainting or other severe symptoms. I warn her (and her partner if present) that the cramping will be significant and she will pass clots and tissue but the pain should not be persistent and/or severe. Finally, I counsel women that she will likely have bleeding for 1-2 weeks but it should slow after several days. If it does not and she continues to have pain and/or heavy bleeding at the 1 week mark she should follow up with a provider for a repeat ultrasound to ensure she does not have retained products of conception and discussion of possible D&C versus continued expectant management.

Lastly, some comments on the words we use in these cases; it matters! Though this is “bread and butter” emergency medicine for us, this day will likely stick in this patient’s, and her families’, minds for the rest of their lives. Do all those things we were taught in medical school when breaking bad news; Sit down, take your time and make eye contact. Say you’re sorry this is happening and you’re sorry there are often no black or white answers in these cases. Don’t use the word abortion and if those words are in her discharge instructions explain why. At the end of my counseling I always tell the woman that it’s not her fault and that there was nothing she could have done to prevent this or prevent an ultimate miscarriage if it does occur. I say “Pregnancy is a very complicated process and it doesn’t always go right. Usually pregnancies that miscarry this early because the baby wasn’t developing normally and would have never developed into a healthy baby”. Be the doctor you would want for your family member in this sensitive, scary and potentially life-altering time!


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Natasha Wheaton, MD

Associate Program Director, UCLA Emergency Medicine

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How to cite this post

[Peer-Reviewed, Web Publication] Sista P,  Lang S (2017, Dec 18). Clinical Concept: Managing first trimester vaginal bleeding in the ED.   [NUEM Blog. Expert Review By Wheaton N]. Retrieved from