Williams Obstetrics
Chapter 9 Abortion
OBGY R1 Lee Eun Suk
Abortion
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Spontaneous abortion
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Induced abortion
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Pathology
Etiology
Fetal Factors
Maternal Factors
Paternal Factors
Categories of Spontaneous Abortion
History of abortion
Indications
Elective (Voluntary) Abortion
Presumption of ovulation after abortion
Abortion
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Termination of pregnancy, either spontaneously or intentionally
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Pregnancy termination prior to 20 weeks’ gestation or less than
500-g birthweight
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Definition vary according to state laws for reporting abortions,
fetal deaths, and neonatal deaths
Spontaneous abortion
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Abortion occurring without medical or mechanical means to
empty the uterus is referred to as spontaneous
Another widely used term is miscarriage
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Pathology
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Hemorrhage into the decidua basinalis, followed by necrosis of
tissues adjacent to the bleeding
If early, the ovum detaches, stimulating uterine contractions
that result in its ovulation
Gestational sac is opened , fluid surrounding a small macerated
fetus or alternatively no fetus is visible → blighted ovum
Spontaneous abortion
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Pathology
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In later abortion, the retained fetus may undergo maceration
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The skull bones collapse, the abdomen distends with bloodstained fluid, and the internal organs degenerate
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The skin softens and peels off in utero or at the slightest tough
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When amnionic fluid is absorbed, the fetus may become
compressed and desiccated → fetal compressus
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The fetus become so dry and compressed that it resembles
parchment - a fetus papyraceous
Spontaneous abortion
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Etiology
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More than 80 percent of abortions occur in the first 12 weeks of
pregnancy
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At least half result from chromosomal anomalies
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After the first trimester, both the abortion rate & the incidence of
chromosomal anomalies decrease
F9-1
Spontaneous abortion
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Etiology
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The risk of spontaneous abortion increases with parity as well as
with maternal and paternal age
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The frequency of abortion increases from 12 percent in women
younger than 20 years to 26 percent in those older than 40 years
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If a woman conceives within 3 months following a term birth
→ incidence of abortion ↑
F9-2
Spontaneous abortion
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Etiology
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The exact mechanism responsible for abortion are not apparent
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In the first 3 months of pregnancy
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Death of the embryo or fetus nearly always precedes spontaneous
expulsion of the ovum
Finding of the cause of early abortion involves ascertaining
the cause of fetal death
In subsequent months
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The fetus frequently does not die before expulsion
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Other explanations for its expulsion should be sought
Spontaneous abortion - Fetal factors
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Abnormal zygotic development
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Early spontaneous abortion commonly display a developmental
abnormality of the zygote, embryo, early fetus, or placenta
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1000 spontaneous abortions analyzed by Hertig and Sheldon
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Half demonstrated degenerated or absent embryos, that is,
blighted ova
F9-3
Spontaneous abortion - Fetal factors
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Aneuploid abortion
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Approximately 50 to 60 percent of embryos and early fetuses
that are spontaneously aborted contain chromosomal abnor-malities
accounting for most of early pregnancy wastage
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Jacobs and Hassold (1980)
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95 percent of chromosomal abnormalities
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d/t maternal gametogenesis error
5 percent → d/t paternal error
T9-1
Spontaneous abortion - Fetal factors
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Aneuploid abortion - Autosomal trisomy
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The most frequently identified chromosomal anomaly associated with
first-trimester abortions
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Most trisomies result from isolated nondisjunction , balanced
structural chromosomal rearrangements are present in one partner in
2 to 4 percent of couples with a history of recurrent abortions
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Autosomes 13, 16, 18, 21, and 22 – most commom
Spontaneous abortion - Fetal factors
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Monosomy X
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The second frequent chromosomal abnormality
Usually results in abortion
Much less frequently in liveborn female infant (Turner syndrome)
Triploidy
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Associated with hydropic placental (molar) degeneration
Incomplete (partial) hydatidiform moles may contain triploidy or
trisomy for only chromosome 16
Spontaneous abortion - Fetal factors
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Tetraploid abortuses
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Rarely are liveborn and most often are aborted early in gestation
Chromosomal structural abnormalities
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Identified only since the development of banding techniques,
infrequently cause abortion
Spontaneous abortion - Fetal factors
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Euploid abortion
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Abort later in gestational than aneuploid
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Three fourths of aneuploid abortions occurred before8 weeks
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Euploid abortions peak at about 13 weeks
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The incidence of euploid abortions increased dramatically after
maternal age exceeded 35 years
Spontaneous abortion – Maternal factors
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Infections
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Uncommon causes of abortion in human
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Listeria monocytogenes
Clamydia trachomatis
Mycoplasma hominis
Ureaplasma urealyticum
Toxoplasma gondii
Spontaneous abortion – Maternal factors
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Chronic debilitating diseases
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In early pregnancy, fetuses seldom abort secondary to chronic
wasting disease such as tuberculosis or carcinomatosis
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Celiac sprue
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Cause both male and female infertility and recurrent abortions
Spontaneous abortion – Maternal factors
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Endocrine abnormalities
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Hypothyroidism
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Diabetes mellitus
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Iodine deficiency associated with excessive miscarriages
Thyroid autoantibodies → incidence of abortion↑
The rates of spontaneous abortion & major congenital malformations
Poor glucose control → incidence of abortion↑
Progesterone deficiency
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Luteal phase defect
Insufficient progesterone secretion by the corpus luteum or placenta
Poor glucose control → incidence of abortion↑
Spontaneous abortion – Maternal factors
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Nutrition
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Dietary deficiency of any one nutrients → not important cause
Drug use and environmental factor
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Tobacco
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Alcohol
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↑ Risk for euploid abortion
More than 14 cigarettes a day → the risk twofold greater ↑
Spontaneous abortion & fetal anomalies → result from frequent alcohol
use during the first 8 weeks of pregnancy
Drinking twice a week → abortion rates doubled ↑
Drinking daily → abortion rates tripled ↑
Caffeine
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At least 5 cups of coffee per day → slightly increased risk of abortion
Spontaneous abortion – Maternal factors
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Drug use and environmental factor
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Radiation
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Contraceptives
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In sufficient doses → abortifacient
When intrauterine devices fail to prevent pregnancy → abortion↑
Environmental toxins
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Anesthetic gases : exact fetal risk of chronic maternal exposure is
unknown
Arsenic, lead, formaldehyde, benzene, ethylene oxide → abortifacient
Video display terminal & accompanying electromagnetic fields
short waves & ultrasound do not increase the risk of abortion
Spontaneous abortion – Maternal factors
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Immunological factors – autoimmune factors
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Recurrent pregnancy loss patients : 15%
Antiphospholipid antibody : most significant
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LCA (lupus anticoagulant), ACA (anticardiolipin Ab)
Reduce prostacyclin production
→ facilitating thromboxane dominant milieu → thrombosis
Prostacyclin : produced by vascular endothelial cell
→ potent vasodilator & inhibit platelet aggregation
Thromboxane A2 : produced by platelets
→ vasoconstrictor & platelet aggregator
Strong association with
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Decidual vasculopathy , placental infarction, fetal growth restriction
Early-onset preeclampsia, recurrent abortion, fetal death
Spontaneous abortion – Maternal factors
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Immunological factors – autoimmune factors
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Therapy of antiphopholipid antibody syndrome
: low dose aspirin, prednisone, heparin, intravenous Ig
→ affect both immune & coagulation system
→ counteract the adverse action of antibodies
Spontaneous abortion – Maternal factors
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Immunological factors – alloimmune factors
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Allogeneity
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Genetic dissimilarities between animals of the same species
Human fetus is allogenic transplant tolerated by mother
Several test for diagnosis of alloimmune factors
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Maternal & paternal HLA comparison
Maternal serum test for blocking antibodies
: blocking antibodies to paternal antigens
: ig G origin
Maternal serum test for antipaternal antibodies
: cytotoxic antibodies to paternal leukocyte
Spontaneous abortion – Maternal factors
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Inherited thrombophilia
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Laparotomy
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Many studies of aggregated thrombophilias
→ excessive recurrent abortions
Surgery performed during early pregnancy
→ no evidence of tncreased abortion
Peritonitis increases the likelihood of abortion
Physical trauma
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Major abdominal trauma → abortion↑
Spontaneous abortion – Maternal factors
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Uterine defects – acquired uterine defects
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Uterine leiomyoma : usually do not cause abortion
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Placental implantation over or in contact with myoma
→ placental abruption, abortion, preterm labor ↑
→ location is more important than size
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Uterine synechiae (Asherman syndrome)
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Partial or complete obliteration of the uterine cavity by adherence of
uterine wall
Cause : destruction of large areas of endometrium by curettage
→ insufficient endometrium to support implantation & menstruation
→ recurrent abortion, amenorrhea, hypomenorrhea
Spontaneous abortion – Maternal factors
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Uterine defects – acquired uterine defects
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Diagnosis of uterine synechiae
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Hysterosalpingogram → characteristic multiple filling defects
Hysteroscopy → most accurate & direct diagnosis
Treatment of uterine synechiae
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Lysis of adhesions via hysteroscopy
Prevention of adherence : IUD
Promotion of endometrial proliferation
: Continuous high-dose estrogen (60-90 days)
Spontaneous abortion – Maternal factors
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Uterine defects – developmental uterine defects
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Consequence of abnormal mullerian duct formation or fusion
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Spontaneously
Induced by in utero exposure to DES (diethylstilbestrol)
Spontaneous abortion – Maternal factors
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Incompetent cervix
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Painless dilatation of cervix in the 2nd or early in the 3rd trimester
→ prolapse & ballooning of membranes into vagina
→ rupture of membrane & expulsion of immature fetus
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Diagnosis in nonpregnant women
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Unless effectively treated, tends to repeat in each pregnancy
Hysterography
Pull-through techniques of inflated Foley catheter balloons
Acceptance without resistance at the internal os of specifically sized
cervical dilators
The use of transvaginal ultrasound in pregnant women
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Cervical length - shortening
Funneling
Spontaneous abortion – Maternal factors
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Incompetent cervix – Etiology
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Previous trauma to the cervix
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Dilatation & curettage
Conization
Cauterization
Abnormal cervical development
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Exposure to DES in utero
Spontaneous abortion – Maternal factors
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Incompetent cervix – Treatment
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The operation is performed to surgically
Reinforcement of weak cervix by some type of purse string suture
( Cerclage )
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Prophylactic surgery : generally performed between 12 & 16weeks
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Should be delayed until after 14 weeks’ gestation
→ Early abortion due to other factors will be completed
The more advanced the pregnancy, the more likely the risk that
surgical intervention stimulate preterm labor or membrane rupture
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Usually do not perform after about 23 weeks
Spontaneous abortion – Maternal factors
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Incompetent cervix – Preoperative evaluation
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Sonography
: Confirm living fetus & exclude major fetal anomalies
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Cervical cytology
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Cultures for gonorrhea, chlamydia, group B streptococci
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Obvious cervical infections → treatment is given
For at least a week before & after surgery → sexual intercourse should
be restricted
Spontaneous abortion – Maternal factors
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Incompetent cervix – Cerclage procedures
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Types of operations commonly used
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McDonald
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Modified Shirodkar
→ 85~90% success rate
Spontaneous abortion – Maternal factors
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Incompetent cervix – Transabdominal cerclage
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Requries laparotomy for
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Placement of cerclage at uterine isthmus level
Cerclage removal, delivery, or both
Indications
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Anatomical defects of cervix
Failed transvaginal cerclage
Spontaneous abortion – Maternal factors
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Incompetent cervix – Complications
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High incidence when performed much after 20 weeks
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Membranes ruptures
Chorioamnionitis
Intrauterine infection
Urgent removal of suture
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Operation fails
Signs of imminent abortion or delivery
Spontaneous abortion – Paternal factors
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Little is known in the genesis of spontaneous abortion
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Chromosomal translocations in sperm can lead to abortion
Categories of spontaneous abortion
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Threatened abortion
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Inevitable abortion
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Complete or incomplete abortion
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Missed abortion
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Recurrent abortion
Categories of spontaneous abortion
Threatened abortion
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Definition
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Any bloody vaginal discharge or bleeding during 1st half of
pregnancy
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Frequency
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Bleeding is frequently slight, but may persist for days or weeks
Extremely common (one out of four or five pregnant women)
Prognosis
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Approximately ½ will abort
Risk of preterm delivery, low birthweight, perinatal death↑
Risk of malformed infant does not appear to be increased
Categories of spontaneous abortion
Threatened abortion
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Symptoms
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Usually bleeding begins first
Cramping abdominal pain follows a few hours to several days later
Presence of bleeding & pain
→ Poor prognosis for pregnancy continuation
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Treatment
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Bed rest & acetaminophen-based analgesia
Progesterone (IM) or synthetic progestational agent (PO or IM)
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Lack of evidence of effectiveness
Often results in no more than a missed abortion
D-negative women with threatened abortion
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Probably should receive anti-D immunoglobulin
Categories of spontaneous abortion
Threatened abortion
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Treatment : slight bleeding persists for weeks
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Vaginal sonography
Serial serum quantitative hCG
Serum progesterone
→ can help ascertain if the fetus is alive & its location
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Vaginal sonography
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Gestational sac(+) & hCG < 1000mIU/ml
→ gestation is not likely to survive
→ If any doubt(+), check the serum hCG level at intervals of 48hrs
→ if not increase more than 65%, almost always hopeless
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Serum progesterone value < 5 ng/ml
→ dead conceptus
Categories of spontaneous abortion
Threatened abortion
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Treatment : after death of conceptus
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Uterus should be emptied
→ examination of all passed tissue whether the abortion is complete
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Ectopic pregnancy should be considered if gestational sac or
fetus are not identified
Categories of spontaneous abortion
Inevitable abortion
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Gross rupture of membrane,evidenced by leaking amnionic fluid,
in the presence of cervical dilatation, but no tissue passed during
1st half of pregnancy
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Placenta (in whole or in part) is retained in the uterus
→ Uterine contractions begin promptly or infection develops
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The gush of fluid is accompanied by bleeding, pain, or fever,
abortion should be considered inevitable
Categories of spontaneous abortion
Complete or incomplete abortion
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Complete abortion
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Following complete detachment & expulsion of the conceptus
The internal cervical os closes
Incomplete abortion
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Expulsion of some but not all of the products of conception during
1st half of pregnancy
The internal cervical os remains open & allows passage of blood
The fetus & placenta may remain entirely in utero or may partially
extrude through the dilated os
→ Remove retained tissue without delay
Categories of spontaneous abortion
Missed abortion
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Retention of dead products of conception in utero for several
weeks
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Many women have no symptoms except persistent amenorrhea
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Uterus remain stationary in size, but mammary changes usually
regress → uterus become smaller
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Most terminates spontaneously
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Serious coagulation defect occasionally develop after prolonged
retention of fetus
Categories of spontaneous abortion
Recurrent abortion
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Definition : Three or more consecutive spontaneous abortions
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Clinical investigation of recurrent miscarriage
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Parental cytogenetic analysis
Lupus anticoagulant & anticardiolipin antibodies assays
Postconceptional evaluation
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Serial monitoring of ß–hCG from missed mens period
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ß–hCG>1500mIU/ml → USG
Maternal serum α-fetoprotein assessment (GA16-18wks)
Amniocentesis → fetal karyotype
Prognosis
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Depends on potential underlying etiology & number of prior losses
INDUCED ABORTION
Induced abortion
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The medical or surgical termination of pregnancy before the time
of fetal viability
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Therapeutic abortion
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Termination of pregnancy before of fetal viability for the purpose
of saving the life of the mother
Induced abortion
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Indication
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Continuation of pregnancy may threaten the life of women or
seriously impair her health
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Persistent heart disease after cardiac decompensation
Advanced hypertensive vascular disease
Invasive carcinoma of the cervix
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Pregnancy resulted from rape or incest
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Continuation of pregnancy is likely to result in the birth of child with
severe physical deformities or mental retardation
Induced abortion
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Elective (voluntary) abortion
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Interruption of pregnancy before viability at the request of the women,
but not for reasons of impaired maternal health or
fetal disease
Counseling before elective abortion
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Continued pregnancy with its risks & parental responsibilities
Continued pregnancy with its risks & its responsibilities of arranged
adoption
The choice of abortion with its risks
Surgical techniques for abortion
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Dilatation and curettage
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Performed first by dilating the cervix & evacuating the product of
conception
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Mechanically scraping out of the contents (sharp curettage)
Vacuum aspiration (suction curettage)
Both
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Before 14 weeks, D&C or vacuum aspiration should be performed
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After 16 weeks, dilatation & evacuation (D&E) is performed
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Wide cervical dilatation
Mechanical destruction & evacuation of fetal parts
Surgical techniques for abortion
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Dilatation and curettage
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Hygroscopic dilators
: swell slowly & dilate cervix → cervical trauma can be minimized
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Laminaria tents
: stem of brown seaweed ( Laminaria digitata or japonica)
→ drawing water from proteoglycan complexes of cervix
→ dissociation allow the cervix to soften & dilate
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Insertion technique : tip rests just at the level of internal os
Usually after 4-6hours, laminaria dilate the cervix sufficiently to allow
easier mechanical dilation & curettage
May cause cramping pain
→ easily managed with 60 mg codeine every 3-4 hours
Surgical techniques for abortion
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Technique for dilatation & curettage
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Remove laminaria → Uterus is sounded carefully to
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Identify the status of the internal os
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Confirm uterus size & position
Further dilation of cervix with Hegar dilator
Surgical techniques for abortion
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Complications : uterine perforation
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2 important determinants
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Skill of the physician
Position of the uterus (retroverted)
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Small defects by uterine sound or narrow dilator
→ often heal without complication
Suction & sharp curettage
→ Considerable intra-abdominal damage risk↑
→ Laparotomy to examine abdominal content (safest action)
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Other complications – cervical incompetence or uterine synechiae
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Surgical techniques for abortion
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Menstrual aspiration
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Aspiration of endometrial cavity using a flexible cannula and syringe
within 1-3 weeks after failure to menstruate
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Several points at early stage of gestation
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Woman not being pregnant
Implanted zygote may be missed by the curette
Failure to recognize an ectopic pregnancy
Infrequently, a uterus can be perforated
Surgical techniques for abortion
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Laparotomy
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Abdominal hysterotomy or hysterectomy
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Indications
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Significant uterine disease
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Failure of medical induction during the 2nd trimester
Medical induction of abortion
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Early abortion
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Outpatient medical abortion is an acceptable alternative to surgical
abortion in women with pregnancies of less than 49 days’ gestation
(ACOG, 2001b)
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Three medications for early medical abortion
 Antiprogestin mifeprostone
 Antimetabolite methotrexate
 Prostaglandin misoprostol
Medical induction of abortion _
2nd trimester abortion
Medical induction of abortion
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Oxytocin
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Successful induction of 2nd trimester abortion is possible with high
doses of oxytocin administered in small volumes of IV fluids
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Satisfactory alternatives to PG E2 for midtrimester abortion
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Laminaria tents inserted the night before
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Chance of successful induction is greatly enhanced
Medical induction of abortion
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Prostaglandins
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Used extensively to terminate pregnancies, especially in the 2nd T
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PG E1, E2, F2α
Technique
: Can act effectively on the cervix & uterus (86~95% effectiveness)
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Vaginal prostaglandin E2 suppository & prostaglandin E1 (misoprostol)
As a gel through a catheter into the cervical canal & lowermost uterus
Injection into the amnionic sac by amniocentesis
Parenteral injection
Oral ingestion
Medical induction of abortion
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Intra-amnionic hyperosmotic solutions
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20-25% saline or 30-40% urea injected into amnionic sac
→ stimulate uterine contraction & cervical dilatation
Action mechanism : prostaglandin mediated ?
Complications of hypertonic saline
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Death
Hyperosmolar crisis (early into maternal circulation)
Cardiac failure
Septic shock
Peritonitis
Hemorrhage
DIC
Water intoxication
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Hyperosmotic urea : less likely to be toxic
Medical induction of abortion
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Antiprogesterone RU 486
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Oral agent used alone in combination with oral PG to effect
abortions in early gestation
High receptor affinity for progesterone binding site
→ Block progesterone action
Abortion rate
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If given within 72 hours
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Single 600mg dose prior 6 weeks → 85%
Addition of oral, vaginal or injected PG → over 95%
Also highly effective as emergency postcoital contraception
Progressively less effective after 72 hours
Side effects
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Nausea, vomiting, & gastrointestinal cramping
Major risk → hemorrhage is a risk if abortion is incomplete
Medical induction of abortion
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Epostane
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3ß-hydroxysteroid dehydrogenase inhibitor
→ blocks the synthesis of endogenous progesterone
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Frequent side effect – nausea
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Hemorrhage is a risk if abortion is incomplete
Consequences of elective abortion
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Maternal mortality
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Legally induced abortion

Relative safe during the first 2 months of pregnancy
( 0.6/100,000 procedures)
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Doubled for each 2 weeks of delay after 8 weeks’ gestation
Consequences of elective abortion
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Impact on future pregnancies
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Fertility : not altered by an elective abortion
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Vacuum aspiration for a first pregnancy
: Do not increase the incidence of
 2nd trimester spontaneous abortions
 Preterm delivery
 Ectopic pregnancy
 LBW infants
Consequences of elective abortion
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Impact on future pregnancies
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Dilatations & curettage for a first pregnancy
: Increased risks for
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Ectopic pregnancy
2nd trimester spontaneous abortions
LBW infants
Multiple elective abortion :
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Not increased the incidence of preterm delivery & LBW infants
Placenta previa
→ increased following multiple sharp curettage abortion procedures
Consequences of elective abortion
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Septic abortion
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Most often associated with criminal abortion

Metritis is usual outcome, but parametritis, peritonitis, endocarditis,
and septicemia may all occur
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Management
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Prompt evacuation of products of conception
Broad-spectrum IV antimicrobials
Resumption of ovulation after abortion
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Ovulation may resume as early 2 weeks after an abortion
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Therefore, if pregnancy is to be prevented,
effective contraception should be initiated soon after abortion