Bleeding in Pregnancy

David C. Jones

BLEEDING IN PREGNANCY

Nothing provokes anxiety during pregnancy like vaginal bleeding. As a harbinger of miscarriage, any amount of bleeding in the first trimester, even spotting, can bring patients in for evaluation.

VAGINAL BLEEDING BEFORE VIABILITY

Perhaps the first and most important question that must be addressed when a woman presents with early pregnancy bleeding is, “Is this an intrauterine pregnancy or could it be an ectopic pregnancy?” Consideration of this question and how to address it is covered in Chapter 3. Once an intrauterine pregnancy has been confirmed, a more in-depth investigation for the etiology of the bleeding may ensue. While it is consid­ered abnormal to experience vaginal bleeding in the first trimester, about 15% of women who subsequently deliver healthy infants at term report they had some amount of early pregnancy bleeding. A similar number of recognized pregnancies experience early bleeding and miscarry. Another 15% of pregnancies miscarry but are unrecognized because they miscarry close to the time of the expected period (1). For a woman with somewhat irregular cycles, this cannot be distinguished from her nor­mal cycle variation.

There are a number of etiologies for early pregnancy loss (Table 8.1). Aneu- ploidy is found in up to half of the miscarriage specimens, but after that, the inci­dence of the listed etiologies is low.

ABORTION

Abortion is defined as a pregnancy loss prior to 20 weeks of gestation from the last menstrual period (LMP) or loss of a fetus weighing the diagnosis of a threatened abortion is made, women are usually counseled to limit their physical activity and avoid sexual activity. While this may seem logical, there is no scientific evidence that any particular behavior on the woman’s part will hasten or prevent a miscarriage. Consequently, the patient must understand that these interventions are merely traditional recom­mendations. Helping the patient understand the lack of benefit of “bed rest” is important because when strict limitations are placed on activity, yet the patient is noncompliant and miscarries, she may be burdened with guilt thinking, “If only I had stayed in bed like I was told...” In truth, if a miscarriage is going to happen, there is nothing available to change that fact.

One question that does come up with early bleeding is whether Rh-negative women need prophylactic Rh immunoglobulin. Rh antigens appear on fetal red cells as early as 38 days of gestation, so sensitization is possible. Because fetomaternal hemorrhage has been documented as early as 7 weeks of gestation, some authorities have advocated the administration of a standard dose of Rh immunoglobulin (300 μg) to Rh-negative women with first trimester bleeding.

Missed Abortion

The diagnosis of “missed abortion” is made when ultrasound confirms the presence of a nonviable intrauterine pregnancy but the cervix is closed. This condition may be seen with an early fetal demise, with an obvious fetus on the ultrasound, or when there is no identifiable fetus. This latter case, which represents either an embryonic demise or failure of the embryo to form, is referred to as an “anembryonic gestation” and was formerly referred to as a “blighted ovum.” Before the advent of ultrasound, this diagnosis was made when the uterus failed to grow in size over an 8-week period (3). The historical concept was that the uterus had not miscarried but had “missed” the fetal demise. When a missed abortion is diagnosed, women generally have three options (4). The first option is to manage the condition expectantly, com­monly referred to as “letting nature take its course.” This option is appealing to women who wish to manage the loss as naturally and “nonmedically” as possible. It is a reasonable option, particularly with first trimester losses. As the gestational age of the loss increases, the risk of disseminated intravascular coagulation increases, but this is not seen in the first trimester. The main disadvantage of this option is that a miscarriage may be more painful and involve more bleeding than a woman is comfortable with, and the timing of the event is uncertain. The second option would be a medical augmentation.

Inevitable Abortion

This diagnosis is made in the first trimester when the cervix is dilated or some of the products of conception (e.g., membranes, fetus, placenta) are visible at the dilated cervix. Once this diagnosis is made, there is no hope for retention of the pregnancy regardless of whether there is fetal heart activity or not. Women essen­tially have the same three options they have for a missed abortion, although less is published on the use of misoprostol for inevitable abortion. In some cases, the miscarriage may be completed simply by grasping the protruding products of conception with ring forceps and gently teasing them out of the uterus. The ring forceps may even be maneuvered into the uterine cavity blindly, though ultra­sound guidance is preferred. In many cases though, suction curettage will be necessary. The use of a small uterine curette to gently scrape the sides of the endometrial cavity to confirm all the tissue has been removed is common; how­ever, one must be very careful not to scrape too aggressively, because this may lead to Asherman syndrome. When the endometrium is scraped off by too aggres­sive a curettage, the anterior and posterior uterine walls may scar together, resulting in a small cavity and future infertility. The suction curettage may be per­formed in the operating room under IV sedation or deeper anesthesia, but in many emergency rooms, it is performed in the emergency department using IV sedation ± paracervical block.

Incomplete Abortion

Incomplete abortion is diagnosed when a portion of the products of conception have been passed but there are still some retained. In this case, the patient may report that she has passed tissue (although sometimes blood clots are mistaken for tissue), and in some instances, she will have brought it in.

Complete abortion

This final type of abortion refers to a miscarriage that has been completed with all tissue passed. This is a frequent outcome up to about 6 weeks of gestation but less common afterwards. Women will notice a dramatic and relatively acute reduction in both cramping and bleeding when the abortion is complete. Once again, ultrasound is the primary means of confirming that all of the products of conception have been expelled from the endometrial cavity.

Postabortion Care

After a pregnancy loss, it is important that women receive follow-up care. After the patient completes her miscarriage, she should be vigilant for evidence of infection or increased bleeding. Some physicians follow β-hCGs after the use of misoprostol to complete a miscarriage to provide additional reassurance that all of the prod­ucts of conception have been passed. It is also reasonable to send the products of conception for pathologic examination to rule out gestational trophoblastic dis­ease (GTD). Rh-negative patients should be given Rh immunoglobulin 300μg for prophylaxis within 72° of their miscarriage if they are past 12 weeks’ gestation. Prior to 12 weeks, while it is not clear that it is necessary, many practitioners give prophylaxis to be safe, and some use the 50-μg dose. The only exception to this is when the father of the pregnancy is known and is known to be Rh negative himself. Published estimates of mistaken paternity range widely (0.8% to 30%; median 3.7%), and inquiring about the chance of mistaken paternity can be quite sensi­tive (9). Consequently, given the risk of Rh sensitization is 2% to 4% after 12 weeks, prophylaxis is sometimes given as a matter of course without even testing the presumptive father.

Normally, women are seen for follow-up by their obstetrician, midwife or potentially in an emergency department follow-up clinic about 2 weeks after their miscarriage has completed.

ADDITIONAL MARKERS

Ultrasound has become nearly indispensable in diagnosing the etiology of early pregnancy bleeding. But its usefulness goes beyond simply diagnosing a demise or a living fetus. The fetal crown-rump length, the main biometric measurement in the first trimester, should be appropriate for the expected gestational age. If the size is lagging and menstrual dating is reliable, it could represent an abnormal gestation. Trisomies 13 and 18 have been shown to exhibit growth restriction as great as 1 week in the first trimester. As noted before, a heart rate over 100 is reassuring. Conversely, a low heart rate is a cause for concern. At 7 weeks of gestation, a fetal heart rate ≤100bpm has a positive predictive value for miscarriage of 75%; this increases to 94% for a heart rate ≤80 bpm (10). Assessment of fetal anatomy can also be helpful. An obvious cystic hygroma may suggest trisomy 21 (Down syn­drome) or Turner syndrome (45,X). In centers with expertise in first trimester prenatal diagnosis, a number of markers that are associated with aneuploidy such as increased nuchal translucency, absent nasal bone, abnormal ductus venosus waveforms, tricuspid regurgitation, abnormal fetal mid-facial angle, and omphalo­cele may be identified. Even the yolk sac is somewhat predictive, as studies have shown that sac diameters outside the normal range (3.8 to 7mm) are associated with poor outcomes (11). When a fetal pole is not visualized, determination must be made as to whether it is likely the pregnancy is an early pregnancy that is not far enough along yet to reliably exhibit a fetal pole or whether it is an anembryonic pregnancy. In these cases, the size of the gestational sac is useful. A gestational sac exceeding a diameter of 25 mm (average of diameter in three planes) that does not exhibit a fetal pole is highly suggestive of a nonviable pregnancy (12,13). A follow-up ultrasound examination in 1 week and/or serial measurements of β-hCG levels are appropriate to confirm nonviability. When the ultrasound examination does not conclusively identify an intrauterine pregnancy in the presence of a positive urine pregnancy test, the diagnosis of an ectopic pregnancy must be considered, and referral to a gynecologist is appropriate. As noted before, this workup is covered in Chapter 3.

CERVICAL INCOMPETENCE

When a woman presents with bleeding in the later stages of the second trimester, one of the important considerations is the diagnosis of an incompetent cervix. The primary symptoms reported may include spotting, bleeding, new onset vaginal discharge or change in a prior discharge, pelvic pressure, and cramping. Classically, the diagnosis of cervical incompetence was made after a woman had two or more losses in the second trimester associated with painless cervical dilation. More recently, consideration was given to making this diagnosis after one loss due to the increasing age at which many women are choosing to have children and the sense that “making” a woman suffer a second midtrimester loss in order to be eligible for some sort of treatment was per­ceived as cruel and insensitive. The advent of transvaginal ultrasound to monitor the cervix for changes before the appearance of frank incompetence has made it easier to manage women with a loss history that does not fit the classical definition. The main risk factors for cervical incompetence include cervical lacerations associated with a prior delivery, traumatic cervical dilation at the time of a dilation and curettage (D&C), dilation and evacuation (D&E), or dilation and extraction (D&X). It is unusual to see cervical incompetence after first trimester D&C in the contemporary era. A prior risk factor was exposure to diethylstilbesterol (DES) in utero. DES was taken in the 1950s and 1960s to prevent miscarriage, and female fetuses exposed to it have an increased incidence of congenital uterine anomalies and cervical incompetency. The last of the population of exposed women should be at the end of their reproductive years.

Women presenting with an incompetent cervix are often diagnosed when a sterile speculum examination shows either the external os of the cervix dilated with the membranes visible at the os or the membranes prolapsing through the cervix and filling the vagina (hourglassing membranes). Occasionally, this diag­nosis is suspected or made based on a transvaginal ultrasound examination either showing the hourglassing membranes or the membranes protruding past the internal os and into the cervical canal. This is often characterized as mem­brane “beaking” or “funneling.” Cervical incompetence carries a significant risk of fetal loss. It is often associated with chorioamnionitis, so the evaluation should include basic physical examination assessment such as temperature and abdom­inal tenderness, as well as a complete blood count with a differential.

In some cases, women will choose to end the pregnancy due to high risk of loss. In cases where the patient chooses to prolong the pregnancy, depending on the actual findings and gestational age, treatment may be expectant or may involve the use of progesterone or a cervical cerclage. When cervical incompetence is sus­pected or diagnosed, the patient should be placed in the Trendelenburg position and, if one is available, a fetal monitor should be used in screening for uterine con­tractions. An obstetrician/gynecologist should always be consulted. Further management and decision-making will be handled by the OBGYN service.

PRETERM PREMATURE RUPTURE OF THE MEMBRANES

Sometimes women who present complaining of bleeding are actually leaking serosanguineous fluid after rupture of the amniotic membranes. The diagnosis is made when the examining physician sees a pool of fluid on sterile speculum exam­ination, the fluid is “fern-positive” referring to the appearance of fern-like pattern of crystals on the glass slide when the fluid evaporates, and the fluid is also “nitrazine- positive” in that it turns nitrazine paper blue. However, both the fern test and the nitrazine test may be falsely positive when there is blood contaminating the fluid pool. A commercially available test identifies trace amounts of PAMG-1, a 34-kDa placental glycoprotein that is abundant in amniotic fluid (2,000 to 25,000ng/mL) but is present in far lower concentrations in maternal blood (5 to 25 ng/mL) and in even lower concentrations in cervicovaginal secretions in the absence of ruptured membranes (0.05 to 0.2ng∕mL) (14-16). Since the test threshold is set at 5ng∕mL, significant blood contamination may also interfere with its results. So, none of the standard tests to detect ruptured membranes are foolproof in the setting of vaginal bleeding. The ultrasound finding of oligohydramnios, while not sufficient to diag­nose rupture of the membranes, is supportive of the diagnosis.

This diagnosis is important because the outcome of these pregnancies is largely dependent on the gestational age at rupture and the amount of retained amniotic fluid. Although the perinatal survival for preterm premature rupture of the membranes (PPROM) at placenta previa was divided into four categories based on a speculum examination and/or very gentle digital cervi­cal examination. Digital examination was often performed in the delivery room as a “double setup” due to the risk that should a complete or partial previa be found the examination itself could dislodge the placenta further causing massive bleed­ing and the need for an immediate cesarean section. Complete previa referred to the case where the placenta completed covered the internal os. Partial previa referred to a placenta that partially covered the internal os. A marginal previa reached to the edge of the internal os and Iow-Iyingplacenta, the least “severe” form of placenta previa, described a placenta that could be reached by the examiner’s finger but did not reach the edge of the internal os.

The introduction of ultrasound and the ability to localize the placenta with­out knowing the dilation of the cervix have made application of the old phraseol­ogy inconsistent. When the placenta is centrally located over the internal os, the diagnosis of a complete placenta previa is relatively straightforward and unam­biguous. However, a dilated cervix is still more of a “potential space” just as the vagina can accept two fingers during an examination but still looks “closed.” So, considering that when the cervix is dilated vessels then run to the placenta. It may also be seen when there is a succenturiate lobe of the placenta, and the vessels connecting the succenturiate lobe to the main placental mass pass close to the cervix. While benign for the mother, this condition is usually fatal for the fetus unless the diagnosis is suspected and made quickly. In either of these condi­tions, if the vessels break, the fetus may rapidly exsanguinate. The velamentous cord insertion variety is more dangerous, because the entire fetal blood volume is passing through the cord, and dividing fetal vessels closer to the cord involves a larger percentage of the circulating blood than the smaller portion that is circu­lating more “root branchings” away downstream in an accessory lobe. This abnormality can be identified by the ultrasound technician using color Doppler or power Doppler, but it is easily missed if the sonographer is not explicitly look­ing for it (27,28). If there is vaginal bleeding without a complete placenta previa, unless the placental cord insertion site is clearly seen, and there is no evidence of a succenturiate lobe, it is most appropriate to do a transvaginal ultrasound using power and/or color Doppler to rule out any fetal vessels in the vicinity of the internal os. Fetal heart rate abnormalities, such as late decelerations, bradycar­dia, or a sinusoidal tracing, will usually lead to a decision to deliver the fetus. In some cases though, particularly if bleeding is not severe and an ultrasound exam­ination is unavailable, there may be time to determine whether bleeding is of maternal or fetal origin. A number of tests are available to make this determina­tion, including some appropriate for bedside use (29). Perhaps the easiest and most convenient test given the chemicals readily available in most obstetrical units is to place a few drops of the blood into a test tube containing a 5% potas­sium hydroxide solution (the standard 10% KOH solution used for detecting yeast and diluted 50:50 with water). Fetal blood remains pink, but maternal blood turns greenish brown. Bleeding vasa previa is appropriately treated by delivery in almost all cases.

Uterine rupture

Uterine rupture is quite rare in an unscarred uterus, and even then, it is usually restricted to the third trimester in women with a prior classical c-section or with multiple prior c-sections. However, when a history is taken, inquiries regarding the prior obstetrical history should not overlook asking whether any prior deliveries were by c-section, whether any of the c-sections were “classical” or had vertical uterine scars, and what the interval between her last c-section and her current pregnancy was. A prior vertical uterine incision, multiple c-sections, and labor all increase the risk of a uterine rupture. A short interdelivery interval also increases the risk of uterine rupture (30-32). Women will present with bleeding but surpris­ingly most do not have severe abdominal pain. Fetal monitoring will usually show obvious fetal compromise. Uterine rupture must be treated with emergency abdominal delivery of the fetus in order to minimize risk of neurologic compro­mise and stop maternal bleeding.

Labor

Sometimes when patients present with bleeding and contractions, it is simply bleeding due to the cervical dilation of labor. This is often referred to as “bloody show” and is rarely heavy enough to be suggestive of an abruption. After pla­centa previa has been ruled out, a digital examination will help determine whether the woman is in labor. These patients are obviously best evaluated in the labor and delivery suite where fetal monitoring is more readily available. Unless delivery is imminent, it is best to transfer them to an appropriate unit or facility.

Nonvaginal sites

Occasionally, women complain of vaginal bleeding when the vagina is not the source of the blood. The most likely complaint is of spotting or finding “blood on the toilet tissue after going to the bathroom.” The most common etiology is bleed­ing from hemorrhoids, which are also more commonly seen during pregnancy. Bleeding from the urinary tract is rarely misidentified as vaginal bleeding. Urinary tract bleeding, such as may be seen with urinary calculi, is rarely grossly bloody, so women are more likely to complain of discolored urine or blood in their urine rather than bleeding per se.

WOMEN ON ANTICOAGULANTS

When women present with excessive bleeding from a non-vaginal site, it is crucial to review their medications, as a considerable number of indications for anticoagulation during pregnancy exist. In addition to the indications for anti­coagulation seen outside of pregnancy such as mechanical heart valves and recent thromboembolism, indications specific to treatment during pregnancy include certain past history of thromboembolism, antiphospholipid antibody syndrome, some familial thrombophilias if there is a history of a prior preg­nancy complicated by intrauterine growth restriction, etc. Anticoagulation dur­ing pregnancy is usually maintained with unfractionated heparin or low molec­ular weight heparin but will occasionally include aspirin. Coumadin is rarely used during pregnancy due to teratogenic effects, but occasionally, it has been used after the period of embryogenesis in women with mechanical heart valves. As the use of unfractionated heparin is on the decline, the partial thromboplas­tin time is not automatically the test to order to evaluate coagulation status. It is important to identify the patient’s anticoagulant so as to pick the correct test for evaluating the degree of anticoagulation. While most women will be able to provide their medication list, if there is any question or the patient is unable to provide a history, contact should be made with her obstetrician or midwife.

SUMMARY

When a patient presents with vaginal bleeding, the triaging is relatively straightforward. One must confirm that the bleeding is really vaginal, rule out an ectopic pregnancy, and rule out a placenta previa. The next step varies based on ges­tational age. In early pregnancy, most of the workup deals with establishing the pre­sumptive viability of the fetus and making management decisions accordingly. In the second half of pregnancy, more serious bleeding complications can directly harm the mother and otherwise normal fetus. Management decisions tend to focus on identi­fying the precise etiology of the bleeding and, if heavy, deciding when it is appropri­ate to deliver for maternal or fetal indications. In many instances of bleeding in all stages of pregnancy, consultation with the patient’s (or on-call) obstetrician or mid­wife may be helpful or mandatory. Throughout the entire episode, the attendant must keep in mind that any degree of vaginal bleeding at any gestational age may be viewed by many patients as one of the most ominous signs for the health of their infant. A calm and sensitive approach will often provide the reassurance needed and in all cases will contribute to a positive perception of the clinical interaction.

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