Unfortunately early pregnancy loss is common. Up to 25% of pregnancies end in a miscarriage. Pregnancy loss is usually a one time occurrence however 1 in 20 couples will experience two miscarriages in an row and 1 in 100 three in a row.
The definition of recurrent pregnancy loss includes those couples who have experienced three or more consecutive spontaneous pregnancy losses.
The main concerns of couples who have experienced one or more miscarriages are; what is the cause, and will it happen again.
The causes can be summarized into:
- Chromosomal abnormalities (abnormal amount of genetic information)
- Implantation failure
- Placentation failure
If genetic errors occur within the embryo from conception there is little to no chance of the pregnancy progressing to term as a baby. This cause can be evaluated by testing the placental tissue of a miscarriage. Usually these chromosomal abnormalities are spontaneous and one off events. They occur however in 50% of miscarriages.
Successful implantation not only requires the correct amount of genetic information but also the maternal uterine environment needs to be healthy enough to support the implanting embryo.
In addition, for a developing embryo to implant successfully and continue on to a pregnancy, the mother’s immune system needs to learn to tolerate the fetus.
If the mothers immune system is too reactive, the fetus can be rejected.
Once the placenta implants it needs to be healthy enough to support the growing embryo. Occasionally the mother has a genetic or acquired condition that causes the blood to clot more readily and development of the placenta is poor.
The risk of miscarriage and risk of recurrence depends on several factors
- Age of the woman (partners age has only a little effect)
- Previous obstetric history – a pregnancy ending in a live birth reduces the risk of miscarriage in subsequent pregnancy.
- Gestational age that previous pregnancy loss occurred.
- A miscarriage that occurs after a long time of infertility.
Effect of age on the risk of miscarriage:
|Age of Woman||Chance of Miscarriage|
|< 20 years||12%|
|20 – 24 years||13%|
|25 – 29 years||15%|
|30 – 34 years||16%|
|35 – 39 years||19%|
|40 – 42 years||25%|
|> 43 years||50%|
Jansen p 96, 2003
Risk of miscarriage according to previous pregnancy outcome:
|Chance of miscarriage in next pregnancy||If you have had one live birth||If you have not had a live birth|
|…after one miscarriage||23%||20%|
|…after two miscarriages||28%||44%|
|…after three miscarriages||33%||28%|
Unfortunately, miscarriages are common, so it is common to have two in a row and even three in a row, but when a couple experience recurrent miscarriages, there are several investigations that can rule out one of the above mentioned underlying condition.
All couples have a different experience. Dr Brims will run through all the possible available tests with you and discuss which tests are best for your situation.
Remember that couples who experience pregnancy loss have a wide range of emotions. It is common to have feelings of self-blame. Miscarriages are never due to anything the woman failed to do or due to stress. If you feel you need further assistance please have a look at the following information.
SIDS and Kids – dedicated to saving lives of children and to supporting bereaved families.
24 hour bereavement support line
1300 308 307
SANDS – miscarriage, stillbirth and newborn death support. 24 hours per day, 7 days per week parent (volunteer) supporters.
1300 072 637
Pregnancy Birth and Baby – non commercial government funded information service. In addition offers a 24 hour per day, 7 day per week counseling line.
1800 882 436
Health direct Australia – free service to talk to a nurse or doctor, 24 hours per day 7 days per week.
1800 882 436