Miscarriage and abortion

Published on 09/03/2015 by admin

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Chapter 8 Miscarriage and abortion

Caroline De Costa, Michael Flynn

Definition. Termination of pregnancy at less than 20 weeks gestation or with the fetus weighing less than 400 g (exact definitions depend on the jurisdiction). ‘Miscarriage’ is usually taken to mean spontaneous abortion. ‘Abortion’ or ‘termination of pregnancy’ (TOP) usually refers to induced abortion (by surgical or medical means).

Incidence. About 15% of all pregnancies spontaneously abort (miscarry) at 6–13 weeks gestation. Up to 80% of spontaneous abortions are diagnosed at 8–12 weeks gestation.

Aetiology of spontaneous abortion

• genetic: chromosomal abnormalities present in up to 50% of first-trimester abortions (e.g. trisomy, monosomy, triploidy)
• fetal malformations (e.g. neural tube defects)
• immunological disorders
• uterine abnormalities
• cervical incompetence
• endocrine disorders (e.g. luteal phase dysfunction, diabetes mellitus)
• infections: listeria, mycoplasma, ureaplasma
• trauma: surgery, amniocentesis, chorionic villus sampling

Presentation and management

Presentation (spontaneous abortion)

• a period of amenorrhoea, followed by vaginal bleeding and cramping lower abdominal pain
• human chorionic gonadotrophin (hCG) positive

Examination

• general examination: colour, blood pressure, pulse
• abdominal examination
• vaginal examination

• bleeding through the cervical os
• bulky uterus

• cervical os may be open, with products of conception at the os or in the vagina

Investigations

• full blood count, blood group
• ultrasound scan of the pelvis

Management

• if bleeding not heavy and patient agrees can ‘wait and see’ (expectant management); complete abortion process may occur naturally
• uterine curettage if incomplete abortion, non-viable pregnancy on ultrasound or patient request
• misoprostol 800 μg vaginally may assist with expulsion of retained products
• anti-D immunoglobulin if patient Rhesus negative

Recurrent abortions

Definition. ‘Recurrent abortions’ is defined as three or more consecutive spontaneous abortions to the same partner.

Prevalence. Prevalence is 1%–2%.

Risk of abortion

• After one abortion, the risk of another abortion at the next pregnancy is 20%–25%.
• After two abortions, the risk rises to 25%.
• After three, the risk is 30%.
• After four, the risk is 35%.
• Despite the many listed causes, most women have no obvious aetiology.

Investigations for recurrent abortions

• depends on history and time of miscarriage, with differing aetiologies presenting at different times
• abnormal parental (both maternal and paternal) karyotype and fetal karyotype; accounts for up to 5% recurrent pregnancy loss and is usually early loss
• assessment of uterine cavity via hysteroscopy or ultrasound
• thyroid function tests
• anticardiolipin and lupus anticoagulant testing
• inheritable thrombophilias (protein C resistance, protein S deficiency, factor V Leiden mutation)

Management of recurrent abortions

• immunosuppresive therapy (prednisone) indications unclear and not supported by trials
• anticoagulation therapy (such as aspirin and/or clexane) if indicated in disorders of inherited thrombophilias

Abortions due to uterine abnormalities

• surgery such as hysteroscopic resection of intrauterine adhesions
• cervical suture

Abortions due to endocrine abnormalities

Treat the cause (e.g. maintain good blood sugar control, and appropriate thyroid replacement).

Support and counselling

Women experiencing spontaneous abortion of a wanted pregnancy, especially those with recurrent abortions, may need effective psychological support and counselling.

Induced abortion

Surgical abortion

• carried out up to 12–13 weeks gestation
• suction curettage, increasingly preceded by misoprostol 400–800 μg 2–4 hours preoperatively to soften and dilate cervix
• cover with antibiotics or take swabs preoperatively and treat infection
• anti-D for Rhesus negative women

Medical abortion

• mifepristone plus misoprostol or misoprostol alone used for late abortion (usually for fetal abnormality or serious maternal conditions) in hospital setting
• misoprostol very effective, but process greatly shortened by the addition of mifepristone
• side effects: nausea, vomiting, diarrhoea from misoprostol; vaginal bleeding and pain from uterine contractions part of abortion process (analgesics should be given)
• anti-D for Rhesus negative women

Support and counselling

• All women undergoing induced abortion need appropriate counselling prior to the procedure, and follow-up, including advice about contraception and safe sex as indicated.
• All women experiencing abortion, whether spontaneous or induced, should be told to report promptly following procedure if pain, fever or offensive discharge occurs. Septic abortion can lead to pelvic inflammatory disease and subsequent infertility.

References

Adelberg A.M. Thrombophilias and recurrent miscarriage. Obstetrical and Gynecological Survey. 2002;57:703-710.

Crenin M.D., Potter C., Holovanisin M., et al. Mifepristone and misoprostol and methotrexate/misoprostol in clinical practice for abortion. American Journal of Obstetrics and Gynecology. 2003;188(3):664-669.

Royal College of Obstetricians and Gynaecologists (RCOG). National Clinical Guidelines. In The care of women requesting induced abortion. RCOG: London; 2004.

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