Spontaneous Abortion: Causes, Types, and Treatment PDF

Abortion  Abortion Termination of pregnancy, either spontaneously or intentionally Pregnancy termination prior to 22 weeks’ gestation or less than 500-g birthweight Definition vary according to state laws for reporting abortions, fetal deaths, and neonatal deaths ...

Abortion  Abortion Termination of pregnancy, either spontaneously or intentionally Pregnancy termination prior to 22 weeks’ gestation or less than 500-g birthweight Definition vary according to state laws for reporting abortions, fetal deaths, and neonatal deaths  Spontaneous abortion  Abortion occurring without medical or mechanical means to empty the uterus is referred to as spontaneous  Another widely used term is miscarriage  Pathology  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  Pathology  In later abortion, the retained fetus may undergo maceration  The skull bones collapse, the abdomen distends with blood- stained fluid, and the internal organs degenerate  The skin softens and peels off in utero or at the slightest tough  When amnionic fluid is absorbed, the fetus may become compressed and desiccated → fetal compressus  The fetus become so dry and compressed that it resembles parchment - a fetus papyraceous  Spontaneous abortion Etiology More than 80 percent of abortions occur in the first 12 weeks of pregnancy At least half result from chromosomal anomalies After the first trimester, both the abortion rate & the incidence of chromosomal anomalies decrease  Spontaneous abortion Etiology  The risk of spontaneous abortion increases with parity as well as with maternal and paternal age  The frequency of abortion increases from 12 percent in women younger than 20 years to 26 percent in those older than 40 years  If a woman conceives within 3 months following a term birth → incidence of abortion ↑  Spontaneous abortion – Maternal factors Infections Uncommon causes of abortion in human Listeria monocytogenes Clamydia trachomatis Mycoplasma hominis Ureaplasma urealyticum Toxoplasma gondii  Spontaneous abortion – Maternal factors Endocrine abnormalities Hypothyroidism Iodine deficiency associated with excessive miscarriages Thyroid autoantibodies → incidence of abortion↑ Diabetes mellitus The rates of spontaneous abortion & major congenital malformations Poor glucose control → incidence of abortion↑ Progesterone deficiency Luteal phase defect Insufficient progesterone secretion by the corpus luteum or placenta  Spontaneous abortion – Maternal factors Nutrition Dietary deficiency of any one nutrients → not important cause Drug use and environmental factor Tobacco ↑ Risk for euploid abortion More than 14 cigarettes a day → the risk twofold greater ↑ Alcohol 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 At least 5 cups of coffee per day → slightly increased risk of abortion  Spontaneous abortion – Maternal factors Inherited thrombophilia  Many studies of aggregated thrombophilias → excessive recurrent abortions Laparotomy  Surgery performed during early pregnancy → no evidence of tncreased abortion  Peritonitis increases the likelihood of abortion Physical trauma  Major abdominal trauma → abortion↑  Spontaneous abortion – Maternal factors  Incompetent cervix  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  Unless effectively treated, tends to repeat in each pregnancy  Diagnosis in nonpregnant women  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  Cervical length - shortening  Funneling  Categories of spontaneous abortion Threatened abortion Threatening Inevitable abortion abortion Inevitable abortion Incomplete Complete or abortion incomplete abortion Complete abortion Missed abortion Septic abortion Missed abortion Recurrent abortion Recurrent abortion Categories of spontaneous abortion Threatened abortion  Definition  Any bloody vaginal discharge or bleeding during 1 st half of pregnancy  Bleeding is frequently slight, but may persist for days or weeks  Frequency  Extremely common (one out of four or five pregnant women)  Prognosis  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 Symptoms Usually bleeding begins first Cramping abdominal pain follows a few hours to several days later Presence of bleeding & pain → Poor prognosis for pregnancy continuation Treatment Bed rest & acetaminophen-based analgesia Progesterone (IM) or synthetic progestational agent (PO or IM) Lack of evidence of effectiveness Often results in no more than a missed abortion D-negative women with threatened abortion  Probably should receive anti-D immunoglobulin Categories of spontaneous abortion Inevitable abortion Gross rupture of membrane,evidenced by leaking amnionic fluid, in the presence of cervical dilatation, but no tissue passed during 1st half of pregnancy Placenta (in whole or in part) is retained in the uterus → Uterine contractions begin promptly or infection develops The gush of fluid is accompanied by bleeding, pain, or fever, abortion should be considered inevitable Categories of spontaneous abortion Complete or incomplete abortion  Complete abortion  Following complete detachment & expulsion of the conceptus  The internal cervical os closes  Incomplete abortion  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  Retention of dead products of conception in utero for several weeks  Many women have no symptoms except persistent amenorrhea  Uterus remain stationary in size, but mammary changes usually regress → uterus become smaller  Most terminates spontaneously  Serious coagulation defect occasionally develop after prolonged retention of fetus Categories of spontaneous abortion Recurrent abortion Definition : Three or more consecutive spontaneous abortions Clinical investigation of recurrent miscarriage Parental cytogenetic analysis Lupus anticoagulant & anticardiolipin antibodies assays Postconceptional evaluation Serial monitoring of ß–hCG from missed mens period  ß–hCG>1500mIU/ml → USG Maternal serum α-fetoprotein assessment (GA16-18wks) Amniocentesis → fetal karyotype Prognosis Depends on potential underlying etiology & number of prior losses INDUCED ABORTION  Induced abortion The medical or surgical termination of pregnancy before the time of fetal viability Therapeutic abortion Termination of pregnancy before of fetal viability for the purpose of saving the life of the mother Surgical techniques for abortion Dilatation and curettage Performed first by dilating the cervix & evacuating the product of conception Mechanically scraping out of the contents (sharp curettage) Vacuum aspiration (suction curettage) Both Before 14 weeks, D&C or vacuum aspiration should be performed After 16 weeks, dilatation & evacuation (D&E) is performed Wide cervical dilatation Mechanical destruction & evacuation of fetal parts Surgical techniques for abortion Dilatation and curettage Hygroscopic dilators : swell slowly & dilate cervix → cervical trauma can be minimized Laminaria tents : stem of brown seaweed ( Laminaria digitata or japonica) → drawing water from proteoglycan complexes of cervix → dissociation allow the cervix to soften & dilate 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 Menstrual aspiration  Aspiration of endometrial cavity using a flexible cannula and syringe within 1-3 weeks after failure to menstruate  Several points at early stage of gestation  Woman not being pregnant  Implanted zygote may be missed by the curette  Failure to recognize an ectopic pregnancy  Infrequently, a uterus can be perforated  Medical induction of abortion Early abortion  Outpatient medical abortion is an acceptable alternative to surgical abortion in women with pregnancies of less than 42 days’ gestation (ACOG, 2001b)  Three medications for early medical abortion  Antiprogestin mifeprostone  Prostaglandin misoprostol  Medical induction of abortion  Prostaglandins  Used extensively to terminate pregnancies, especially in the 2nd T  PG E1, E2, F2α  Technique : Can act effectively on the cervix & uterus (86~95% effectiveness)  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 Intra-amnionic hyperosmotic solutions 20-25% saline or 30-40% urea injected into amnionic sac → stimulate uterine contraction & cervical dilatation Action mechanism : prostaglandin mediated ? Complications of hypertonic saline Death Hyperosmolar crisis (early into maternal circulation) Cardiac failure Septic shock Peritonitis Hemorrhage DIC Water intoxication Hyperosmotic urea : less likely to be toxic  Medical induction of abortion Antiprogesterone RU 486 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 Single 600mg dose prior 6 weeks → 85% Addition of oral, vaginal or injected PG → over 95% If given within 72 hours Also highly effective as emergency postcoital contraception Progressively less effective after 72 hours Side effects Nausea, vomiting, & gastrointestinal cramping Major risk → hemorrhage is a risk if abortion is incomplete