Spontaneous Abortion

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1st Trimester Bleeding
Any bleeding during the first trimester of pregnancy is abnormal. The cause may be trivial or serious, but it is always abnormal.

Bleeding during the first trimester is common. At least one-third of all pregnant women will experience some degree of bleeding (perhaps only light spotting) during this time. Half of those will ultimately lose the pregnancy, while the other half will continue their pregnancy normally and without any further problems.

Clinical evaluation of women with first trimester bleeding involves looking for evidence of:

  • Inevitable abortion
  • Incomplete abortion
  • Ectopic pregnancy
  • Gestational trophoblastic disease
  • Other miscellaneous causes for bleeding, including cervical/vaginal trauma, infection, and polyps

Depending on the clinical circumstances, evaluation may include a history, physical exam, and such laboratory tests as ultrasound, quantitative HCG, and progesterone.

Loss of a pregnancy during the first 20 weeks of pregnancy, at a time that the fetus cannot survive. Such a loss may be involuntary (a “spontaneous” abortion), or it may be voluntary (“induced” or “elective” abortion).

Miscarriage is the layman’s term for spontaneous abortion, an unexpected 1st trimester pregnancy loss. Since the term “spontaneous abortion” may be misunderstood by laymen, the word “miscarriage” is sometimes substituted.

Abortions are further categorized according to their degree of completion. These categories include:

  • Threatened
  • Inevitable
  • Incomplete
  • Complete
  • Septic

Such losses are common, occurring in about one out of every 6 pregnancies.

For the most part, these losses are unpredictable and unpreventable. About 2/3 are caused by chromosome abnormalities incompatible with life. About 30% are caused by placental malformations and are similarly not treatable. The remaining miscarriages are caused by miscellaneous factors but are not usually associated with:

  • Minor trauma
  • Intercourse
  • Medication
  • Too much activity

Following a miscarriage, the chance of having another miscarriage with the next pregnancy is about 1 in 6. Following two miscarriages in a row, the odds of having a miscarriage with the next pregnancy is still about 1 in 6. After three consecutive miscarriages, the risk of having a fourth is greater than 1 in 6, but not very much greater.

Threatened Abortion
A threatened abortion means the woman has experienced symptoms of bleeding or cramping.

At least one-third of all pregnant women will experience these symptoms. Half will go on to abort spontaneously. The other half will see the bleeding and cramping disappear and the remainder of the pregnancy will be normal. These women who go on to deliver their babies at full term can be reassured that the bleeding in the first trimester will have no effect on the baby and that you expect a full-term, normal, healthy baby.

Treatment of threatened abortion should be individualized. Many obstetricians recommend bedrest in some form for women with a threatened abortion. There is no scientific evidence that such treatment changes the outcome of the pregnancy in any way, although some women may feel better if they are at rest. Other obstetricians feel that being up and active is psychologically better for the patient and will not change the risk of later miscarriage. Among these active women, strenuous physical activity is usually restricted, as is intercourse.

Complete Abortion
A complete abortion means that all tissue has been passed through the cervix.

This is the expected outcome for a pregnancy which was not viable from the outset. Often, a fetus never forms (blighted ovum). The bleeding and cramping steadily increases, leading up to an hour or two of fairly intense cramps. Then the pregnancy tissue is passed into the vagina.

An examination demonstrates the active bleeding has slowed or stopped, there is no tissue visible in the cervix, and the passed tissue appears complete. Save in formalin any tissue which the patient has passed.

RH negative women receive an injection of Rhogam (hyperimmune Rh globulin) within 3 days of the abortion. It may still be effective in preventing Rh sensitization if given within 7-10 days.

They are encouraged to have a restful day or two and a follow-up examination in a week or two. Bleeding similar to a menstrual flow will continue for a few days following the miscarriage and then gradually stop completely. A few women will continue to spot until the next menstrual flow (2-6 weeks later). A pregnancy test is not helpful in these situations, as clinically significant levels of HCG will remain in the mother’s bloodstream for weeks following a complete abortion. The mean time to HCG washout is about 30 days.

Women seeking another pregnancy as soon as possible are often advised to wait a month or two to allow them to re-establish a normal uterine lining and to replenish their reserves. Prolonged waiting before trying again is not necessary.

Some physicians recommend routinely giving a uterotonic drug (such a Methergine 0.2 mg PO TID x 2 days) to minimize bleeding and encourage expelling of any remaining fragments of tissue. It also may increase cramping and elevate blood pressure. Antibiotics (such as doxycycline or amoxicillin) are likewise prescribed by some.

If fever is present, IV broad-spectrum antibiotics are wise, to cover the possibility that the complication of sepsis has developed. If the fever is high and the uterus tender, septic abortion is probably present and you should make preparations for D&C to remove any retained products of conception that might prolong the recovery.

If hemorrhage is present, bedrest, IV fluids, oxygen, and blood transfusion may be necessary. Continuing hemorrhage suggests an “incomplete abortion” rather than a “complete abortion” and your treatment should be reconsidered.

Incomplete Abortion
With an incomplete abortion, some tissue remains behind inside the uterus.

These typically present with continuing bleeding, sometimes very heavy, and sporadic passing of small pieces of pregnancy tissue.

Ultrasound may reveal the presence of identifiable tissue within the uterus. Serial quantitative HCG levels can be measured if there is doubt about the completeness of a miscarriage.

Left alone, many of these cases of incomplete abortion will eventually resolve spontaneously, but so long as there are non-viable pieces of tissue inside the uterus, the risks of bleeding and infection continue.

Treatment consists of converting an incomplete abortion into a complete abortion. Usually, this is done with a D&C (dilatation and curettage). This minor operation can be performed under local anesthesia and takes just a few minutes.

Alternatively, bedrest and oxytocin, 20 units (1 amp) in 1 Liter of any crystalloid IV fluid at 125 cc/hour may help the uterus contract and expel the remainder of the pregnancy tissue, converting the incomplete abortion to a complete abortion.

Alternatively, ergonovine 0.2 mg P.O. or IM three times daily for a few days may be effective.

If fever is present, broad-spectrum antibiotics are wise.

Any tissue fragments visibly protruding from the cervical os can be grasped with a ring or dressing forceps and gently pulled straight out. This simple and safe procedure will have a beneficial effect on the bleeding.

Inevitable Abortion

Inevitable abortion means that a miscarriage is destined to occur, but no tissue has yet been passed. This is sometimes called a “missed abortion.”

This diagnosis is best made by ultrasonic visualization of the fetal heart and noting no movement. Alternatively, demonstrating no growth of the fetus over a one week period in early pregnancy confirms an inevitable abortion. Falling levels of HCG are an ominous sign and strongly suggest the pregnancy is no longer living.

Two alternative approaches are considered for an inevitable abortion: D&C or awaiting a spontaneous abortion. Each approach has its own merits and limitations:

  • Awaiting a spontaneous abortion offers the benefit of avoiding surgery, but commits the patient to a day or more of heavy bleeding and cramping. A few of these women will experience an incomplete abortion and will need to have a D&C anyway.
  • Performing a D&C has the benefit of quickly resolving the issue of a missed abortion, but commits the patient to a surgical procedure which carries some risks.

Septic Abortion
During the course of any abortion, spontaneous or induced, infection may set in.

Such infections are characterized by fever, chills, uterine tenderness and occasionally, peritonitis. The responsible bacteria are usually a mixed group of Strep, coliforms and anaerobic organisms. These patients display a spectrum of illness, ranging from mild, to very severe.

Usual treatment consists of bedrest, IV antibiotics, uterotonic agents, and complete evacuation of the uterus. If the patient does not respond to these measures and is deteriorating, surgical removal of the uterus, tubes and ovaries may be life-saving.

Evacuation of the uterus can be initiated with oxytocin, 20 units (1 amp) in 1 Liter of any crystalloid IV fluid at 125 cc/hour or ergonovine 0.2 mg P.O. or IM three times daily. If the patient response is not favorable, or if the patient is quite ill, D&C is the next step.

IV antibiotics should be started immediately. Among many good choices for this treatment are:

  • Ampicillin 2 gm IV Q6 hours, plus
  • Gentamicin 1-1.5 mg/kg IV Q8 hours, plus
  • Clindamycin 900 mg IV Q8 hours

Another good choice could be:

  • Imipenem-cilastin 250-500 mg IV Q6 hours
  • Aztreonam 1-2 gm IV Q12 hours, plus
  • Metronidazole 1 gm IV loading dose, then 500 gm IV maintenance dose

Last Modified Jul 21, 2016 @ 1:06 pm

Last Modified Jul 21, 2016 @ 1:06 pm

A Training Simulation in Introductory Obstetrics & Gynecology