Abortion; Types, Causes, Symptoms, Diagnosis, Treatment

Abortion; Types, Causes, Symptoms, Diagnosis, Treatment

Abortion is the ending of pregnancy due to removing an embryo or fetus before it can survive outside the uterus. An abortion that occurs spontaneously is also known as a miscarriage. When deliberate steps are taken to end a pregnancy, it is called an induced abortion, or less frequently as an “induced miscarriage”. The word abortion is often used to mean only induced abortions. A similar procedure after the fetus could potentially survive outside the womb is known as a “late termination of pregnancy” or less accurately as a “late term abortion”.



Abortion is the loss or failure of an early pregnancy and it is defined in several forms: complete, incomplete, inevitable, missed, septic, and threatened.

Causes of Abortion

  • ovular or fetal
  •  maternal environment
  • paternal factor
  • unknown

Ovo-fetal factors (60%)

  • The ovo-fetal factors usually operate in early fetal wastage. Meticulous histological and cytogenetic study of the abortus reveals gross defects in the ovum or the fetus. The defects include
  • Malformation
  • A blighted ovum (ovum without embryo)
  • The death or disease of the fetus often precedes the expulsive action of the uterus.
  • Interference with the circulation in the umbilical cord by knots, twists or entanglements may cause death of the fetus and its expulsion.
  • Low attachment of the placenta or faulty placental formation (circumvallate) may interfere with placental circulation.
  • Twins or hydramnios (acute)  by rapidly stretching the myometrium may cause abortion.

 Maternal factors (15%)

maternal factors usually operate in late abortion.

(a) Maternal illness

  • Infection –  viral infection, especially of rubella and cytomegalic inclusion disease, produces congenital malformations and abortion. The viruses of hepatitis, parvovirus, influenza, have got lethal action on the fetus causing its death and expulsion. Parasitic (malaria) and protozoal infection (toxoplasmosis) may produce abortion if contracted in early pregnancy. Hyperpyrexia may precipitate abortion by increasing uterine irritability.
  • Maternal hypoxia and shock – acute or chronic disease, heart failure, severe anemia or anesthetic complications may produce an anoxic state which may precipitate abortion. Severe gastroenteritis or cholera which is prevalent in the tropics is often an important cause.
  • Chronic illness – hypertension, chronic nephritis, and chronic wasting disease are responsible for late abortion by producing placental infarction resulting in fetal anoxia.
  • Endocrine factor – an increased association of abortion is found in conditions of hypothyroidism, hyperthyroidism and diabetes mellitus. Inadequate corpus luteal state is considered to be related to unsatisfactory ovular growth and development and hence its expulsion.

(b) Trauma

  • Direct trauma – on the abdominal wall by blow or fall may be related to abortion. But fortunately, except in abortion prone women, pregnancy remains undisturbed.
  • Psychic –  emotional upset or change in environment may lead to abortion by affecting the uterine activity.
  • In susceptible individual, even a minor trauma in the form of a journey along the rough road, internal examination in early months or eliciting Hegar’s sign or sexual intercourse in early months is rough to excite abortion.
  • Amniocentesis –  chorion villus sampling or abdominal surgery in early months may cause abortion.

(c) Toxic agents – environmental toxins like lead, arsenic, anesthetic gases, tobacco, caffeine, alcohol, radiation in excess amount increase the risk of abortion. Drugs used for epilepsy or antimalarial preparations (quinine) are not so much harm when used in therapeutic doses so as to cause abortion.

(d) cervico-uterine factors –  these are related to the second-trimester abortions.

  • Cervical incompetence –  either congenital or acquired is one of the commonest causes of midtrimester and recurrent abortions.
  • Congenital malformation of the uterus –  in the form of the bicornuate or septate uterus may be responsible for midtrimester or recurrent abortion.
  • Uterine tumor – (fibroid) especially of the submucous variety might be responsible not only for infertility but also for abortion due to distortion of the uterine cavity and increased uterine irritability.
  • Retroverted uterus –  is not responsible for abortion but its association might be due to its failure to rectify between 12-14weeks due to adhesions or due to trauma during sexual intercourse or it could be due toa disturbance in uterine vascularity.

(e)Immunological – presence of autoimmune factor like lupus anticoagulants and antiphospholipid antibodies increase the risk of abortion.

(f)  Blood group incompatibility – incompatible ABO group mating may be responsible for early pregnancy wastage and often recurrent but Rh incompatibility is a rare cause of death of the fetus before 28 weeks. Couple with group ‘A’ husband and group ‘o’ wife has got a higher incidence of abortion.

(g)Premature rupture of membranes – inevitably leads to abortion.

(h)Dietetic factors – deficiency of folic acid or vitamin E is often held responsible.

Paternal factors

Defective sperm, contributing half of the number of the chromosomes to the ovum, may result in abortion, but it is difficult to prove. However, some women who abort habitually may have normal pregnancies following marriage with a different man.

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Unknown (25%)

In spite of the numerous factors mentioned, it is indeed difficult, in a majority, to pinpoint the cause of abortion in clinical practice. Too often, more than one factor is present.




Complete abortion

A complete abortion is the termination of a pregnancy before the age of viability, typically defined as occurring at less than 20 weeks from the first day of the last normal menstrual period or involving a fetus of weight less than 500 g. Most complete abortions generally occur before 6 weeks or after 14 weeks of gestation.


Incomplete abortion

An incomplete abortion is the spontaneous passage of some, but not all, of the products of conception.


Inevitable abortion

A pregnancy in which rupture of the membranes and/or cervical dilation takes place during the fi rst half of pregnancy is labeled an inevitable abortion. Uterine contractions typically follow, ending in spontaneous loss of the pregnancy for
most patients.


Missed abortion

A missed abortion is the retention of a failed intrauterine pregnancy for an extended period. A septic abortion is a variant of an incomplete abortion in which infection of the uterus and its contents has occurred.


Threatened abortion

A threatened abortion is a pregnancy that is at risk for some reason. Most often, this applies to any pregnancy in which vaginal bleeding or uterine cramping takes place but no cervical changes have occurred.


How to differentiate type of abortion?

• Threatened abortion: slight vaginal bleeding is seen, with or without feeble uterine contractions. The characteristic finding of this type of abortion is the absence of cervical dilation.

• Inevitable abortion: is characterized by cervical dilation together with more severe vaginal bleeding and uterine contractions. Moreover, the uterine contractions become stronger as time progresses, bleeding becomes more severe, and the process ends by expulsion of the uterine contents.

• Complete abortion: when the entire fetus, placenta, and membranes are eliminated.

• Incomplete abortion: when the fetus is expelled and all or part of the placenta remains inside the uterus. In the latter case, vaginal bleeding may continue as long as the placental parts are not removed spontaneously or by intervention.

• Missed abortion: the fetus (if present) dies but the placenta is not detached from the uterine walls. In such cases the amniotic fluid is reabsorbed, and the fetus undergoes a process of dehydration and mummification.

Types Of Medical Abortion Procedures

Medical abortion
Abortions completed with medication, called medical abortions, can be performed within 64 days of gestation. Days of gestation are the number of days beginning on the first day of your last menstrual period.

Medications used to induce abortion include:

  • Mifepristone (Mifeprex) – Known as RU-486, mifepristone is taken orally as a pill. Approved for use in the United States in 2000, this drug counters the effect of progesterone, a hormone necessary for pregnancy. More than 3 million women in Europe and China have received this drug to end a pregnancy.Side effects include nausea, vomiting, vaginal bleeding and pelvic pain. These symptoms usually can be treated with medications. In rare instances, there may be heavy bleeding. In that case, you may be admitted to a hospital and given blood transfusions. Mifepristone is more effective when another medication, such as misoprostol (Cytotec), is taken 24 to 48 hours later. It causes the uterus to contract. Between 92% and 97% of women who receive mifepristone in combination with, or followed by, misoprostol have a complete abortion within 2 weeks.
  • Misoprostol (Cytotec) – Misoprostol is almost always used in conjunction with mifepristone to induce a medical abortion. Misoprostol is a prostaglandin-like drug that causes the uterus to contract. One form can be taken by mouth. The other is inserted into the vagina. The vaginal form is less likely to cause diarrhea, nausea and vomiting. However, the vaginal form is associated with a higher risk of infection. To decrease the risk of infections, many doctors now prefer the oral form of misoprostol, followed by a 7 day course of the antibiotic doxycycline.
  • Methotrexate – Methotrexate is used less often since the U.S. Food and Drug Administration (FDA) approved mifepristone. However, methotrexate may be used in women who are allergic to mifepristone or when mifepristone is not available. Methotrexate usually is injected into a muscle. Between 68% and 81% of pregnancies abort within 2 weeks; 89% to 91% abort after 45 days. Methotrexate is the medication most often used to treat ectopic pregnancies, which are implanted outside the womb. It kills the fast-growing tissue of ectopic pregnancies. When doctors give methotrexate to treat ectopic pregnancy, pregnancy hormone levels must be monitored until levels are undetectable in a woman’s bloodstream. This monitoring is not necessary when methotrexate is used for medical abortions, where the pregnancy is known to be implanted in the womb.
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In rare instances when a pregnancy continues after the use of these medications, there is a risk that the baby will be born deformed. The risk is greater with the use of misoprostol. If the pregnancy tissue does not completely leave the body within two weeks of a medical abortion, or if a woman bleeds heavily, then a surgical procedure may be needed to complete the abortion. Approximately 2% to 3% of women who have a medical abortion will need to have a surgical procedure, usually suction dilation and curettage (D and C), also called vacuum aspiration.

A woman should not have a medical abortion if she:

  • Is more than 64 days pregnant (counted from the first day of the last menstrual period)
  • Has bleeding problems or is taking blood thinning medication
  • Has chronic adrenal failure or is taking certain steroid medications
  • Cannot attend the medical visits necessary to ensure the abortion is completed
  • Does not have access to emergency care
  • Has uncontrolled seizure disorder (for misoprostol)
  • Has acute inflammatory bowel disease (for misoprostol)

Surgical abortion

  • Menstrual aspiration – This procedure, also called menstrual extraction or manual vacuum aspiration, is done within one to three weeks after a missed menstrual period. This method can also be used to remove the remaining tissue of an incomplete miscarriage (also called a spontaneous abortion). A doctor inserts a small, flexible tube into the uterus through the cervix and uses a handheld syringe to suction out the pregnancy material from inside the womb. Local anesthesia is usually applied to the cervix to decrease the pain of dilating the cervix. Local anesthesia numbs only the area injected and you remain conscious. Medication given intravenously (into a vein) can lessen anxiety and the body’s general response to pain. Menstrual aspiration lasts about 15 minutes or less.
  • Suction or aspiration abortion – Sometimes called a suction D & C (for dilation and curettage), this procedure can be done up to 13 weeks after the first day of the last menstrual period. Suction D & C is the procedure most commonly used to end a pregnancy. The cervix is dilated (widened) and a rigid hollow tube is inserted into the uterus. An electric pump sucks out the contents of the uterus. The process takes about 15 minutes. Local anesthesia is usually applied to the cervix to minimize the pain of dilating the cervix. Medication given intravenously (into a vein) may help to decrease anxiety and relieve pain.
  • Dilation and curettage (D and C) – In a dilation and curettage, the cervix is dilated and instruments with sharp edges, known as curettes, are used to remove the pregnancy tissue. Suction is often used to make sure all the contents of the uterus are removed. The earlier in pregnancy this procedure is done, the less the cervix has to be dilated, which makes the procedure easier and safer.
  • Dilation and evacuation (D and E) – This is the most common procedure for ending a pregnancy between 14 and 21 weeks. It is similar to a suction D and C but with larger instruments. The cervix has to be dilated or stretched open to a size larger than required for a D and C. Suction is used along with forceps or other special instruments to ensure all the pregnancy tissue is removed. The procedure takes more time than other abortion procedures.
  • Abdominal hysterotomy – This is a major operation to remove the fetus from the uterus through an incision in the abdomen. This is rare but may be necessary if a D and E cannot be done. Anesthesia will make you unconscious for this surgery.

Induction of labor

After 14 weeks of pregnancy, abortion can be done by giving medication that causes the woman to go into labor and deliver the fetus and the placenta. The procedure usually requires hospitalization for more than a day because it involves labor and delivery. Sometimes dilation and evacuation is necessary to completely remove the placenta. Labor can be induced in one of three ways:

  • Invasive – Injecting labor inducing medications by passing a needle through the abdomen and into the uterus, usually within the amniotic sac
  • Noninvasive – Giving labor inducing medications by mouth, intravenously (into a vein), through an injection into a muscle, or inserted in the vagina
  • A combination – of invasive and noninvasive approaches. Usually necessary when abortion is done late in the second trimester, before 24 weeks
  • Methotrexate is given orally or by injection during the first office visit.
  • Antibiotics are also given in order to prevent infection.
  • Misoprostol tablets are given orally or inserted vaginally about 3 to 7 days later. This can be done at home.
  • This procedure will usually trigger contractions and expel the fetus. The process may take a few hours or as long as a few days.
  • A physical exam is given a week later to ensure that the abortion procedure is complete and to check for complications.
  • Methotrexate is primarily used in the treatment of cancer and rheumatoid arthritis because it attacks the most rapidly growing cells in the body. In the case of abortion, it causes the fetus and placenta to separate from the lining of the uterus. Using the drug for this purpose is not approved by the FDA.
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The side effects and risks of Methotrexate & Misoprostol include the following

  • Cramping, nausea, diarrhea, heavy bleeding, fever
  • The procedure is unsuccessful approximately 5% of the time with the potential of requiring an additional surgical abortion procedure to complete the termination.
  • It is not advised for women who have anemia, bleeding disorders, liver or kidney disease, seizure disorder, acute inflammatory bowel disease, or who use an intrauterine device (IUD).

Mifepristone (Mifeprex) and Misoprostol

Mifepristone (Mifeprex) and misoprostol is a medical abortion procedure used up to the first 7 to 9 weeks of pregnancy. It is also referred to as RU-486 or the abortion pill.

  • A physical exam is first given in order to determine eligibility for this type of medical abortion procedure. You are not eligible if you have any of the following: ectopic pregnancy, ovarian mass, IUD, corticosteroid use, adrenal failure, anemia, bleeding disorders or use of blood thinners, asthma, liver or kidney problems, heart disease, or high blood pressure. You will be given antibiotics to prevent infection.
  • Mifepristone is given orally during your first office visit. Mifepristone blocks progesterone from the uterine lining, causing the lining to break down, preventing the ability to continue a pregnancy.
  • Misoprostol tablets are taken orally or inserted vaginally about 36 to 72 hours after taking the mifepristone. The tablets will cause contractions and expel the fetus. This process may take a few hours or as long as a few days.
  • A physical exam is given two weeks later to ensure the abortion was complete and to check for complications.

The side effects and risks of Mifepristone & Misoprostol include the following:

  • Cramping, nausea, vomiting diarrhea, heavy bleeding, infection
  • The procedure is unsuccessful approximately 8-10% of the time with the potential of requiring an additional surgical abortion procedure to complete the termination.
  • It is not advised for women who have anemia, bleeding disorders, liver or kidney disease, seizure disorder, acute inflammatory bowel disease or use an intrauterine device (IUD).


Researchers have identified a large number of statistically significant risk factors that identify which women are at greatest risk of experiencing one or more severe reactions to abortion.   The following is list of risk factors identified by the American Psychological Association Task Force on Mental Health and Abortion in their 2008 report:

  • terminating a pregnancy that is wanted or meaningful
  • perceived pressure from others to terminate a pregnancy
  • perceived opposition to the abortion from partners, family, and/or friends
  • lack of perceived social support from others
  • various personality traits (e.g., low self-esteem, a pessimistic outlook, low-perceived control over life)
  • a history of mental health problems prior to the pregnancy
  • feelings of stigma
  • perceived need for secrecy
  • exposure to antiabortion picketing
  • use of avoidance and denial coping strategies
  • feelings of commitment to the pregnancy
  • ambivalence about the abortion decision
  • low perceived ability to cope with the abortion
  • history of prior abortion
  • late term abortion
  • being an adolescent (not an adult)
  • having a non-elective (therapeutic or coerced) abortion
  • prior history of abortion (having a second or third abortion, or more)




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