Miscarriage

A miscarriage is defined as the loss of a pregnancy before 20 weeks gestation. It is also referred to as a spontaneous abortion or pregnancy loss. Most miscarriages occur within the first trimester, defined as the first 12 weeks of pregnancy.

The incidence of miscarriage becomes greater with the age of the mother or the father. The chance of miscarriage is approximately double for women 40-44 years versus women 30-34 years of age.

Miscarriages occur in up to 44% of all Assisted Reproductive Technology (ART) pregnancies and light bleeding (or spotting) occurs in up to 55% of all ART pregnancies.  Note that light bleeding or spotting does not always  lead to miscarriage.

What To Do If You Suspect You Are Having a Miscarriage:

If you experience heavy bleeding and/or bleeding associated with increased abdominal pain you should contact your specialist gynaecologist or a nurse at the fertility centre. In an emergency, attend the Accident and Emergency Department at a public hospital.

Emotional Aspects:

Experiencing miscarriage can create feelings of shock, disbelief, guilt, anger, sadness, loneliness and depression. There is a period of grief and repeated miscarriages can intensify these feelings. Grieving is a very personal experience and each partner may experience it differently. The support of the fertility centre or other counsellor may be useful, or patients may seek help from a formal support group whose members have had a similar experience.

Types of Miscarriage: 

  • Complete abortion
  • Incomplete abortion – a D&C is usually required
  • Inevitable abortion – blood tests indicate a drop in hormones and the pregnancy will not be ongoing
  • Other non-progressive pregnancies including ectopic pregnancy, blighted ovum and molar pregnancy

Causes of Miscarriage:

These are many and varied and the patient’s doctor is likely to do routine tests to exclude most of the causes listed below:

1. GENETIC

2. UTERINE ABNORMALITIES

  • Septate Uterus – a central ridge or ‘septum’ of tissue protrudes into the uterus causing an inadequate blood supply which cannot support normal foetal growth, causing miscarriage. Although 3% of females have this congenital abnormality, only 1.5% will have reproductive difficulty.
  • Uterine Fibroids (non cancerous tumours) can interfere will the implantation or growth of a foetus. 

3. CERVICAL ABNORMALITIES

  • Cervical Incompetence – where the cervix at the lower end of the uterus is too weak to support a pregnancy without surgical intervention. 16% of mid-trimester miscarriages (16-20 weeks) are caused by this condition. Cerclage or a cervical stitch is sometimes considered.

4. HORMONAL ABNORMALITIES

  • Thyroid – Hypo or Hyperthyroid antibodies are detectable by a blood test and can be treated by medication.
  • Low Progesterone in Luteal Phase and Pregnancy – or low progesterone can be detected by blood test and endometrial biopsy. Vaginal progesterone pessaries or Crinone vaginal gel may be used to treat this.
  • Prolactin (a pituitary hormone) – an increase is detected by blood test and can be corrected by medication.

5. MATERNAL INFECTION

  • Infections such as chlamydia requires both partners to be treated with antibiotics and retested before attempting further pregnancy.

6. MATERNAL ILLNESS

  • Congenital heart disease, severe kidney disease or diabetes can cause miscarriage.
  • PCOS Polycystic Ovaries Syndorome is now recognised to be one of the conditions which increase the risk of miscarriage. This is due to the higher blood levels of the hormone called LH often found in women with PCOS.

7. IMMUNE SYSTEM

  • This is a complex area and is under intense investigation by researchers. Immunoglobulins or antibodies such as lupus anticoagulants, anticardiolipins and antiphospholipids can affect foetal development, often resulting in miscarriage. Alteration in immunologic response of the mother against the pregnancy, causing rejection of the father’s foreign material on the foetus, can also result in miscarriage. Any woman with these disorders is seen as high risk and needs careful treatment and monitoring before and throughout the pregnancy.


8. ENVIRONMENT AND LIFESTYLE

  • Smoking, drinking alcohol and illicit drug use can increase the risk of miscarriage.