Preconception series: Miscarriages

2 mins to read

Approximately 15% of all known pregnancies end in miscarriage. Only 1-2% will experience recurrent (>3) miscarriage.

Pregnancy and preconceptionEveryday health

Stats

Up to 70% of miscarriages before 6 weeks are as a result of chromosomal problems. These abnormalities increase with age in both the male and female. The graph below shows the increased risk of miscarriage with increasing age.

Figure 1: Risk of Miscarriage and Age

risk-of-miscarriage-and-age

There may be another factor behind the age-related increase in miscarriage risk – the strength of the egg’s energy metabolism. A woman’s eggs develop while she is still in her own mothers uterus and they have to last for life. So in fact a woman’s eggs are older than her! In every cell of the body, energy is produced by tiny structures called mitochondria. When an egg is fertilised, the embryo receives all of its mitochondria from the mother. Because an embryo's mitochondria come from the egg, the mitochondria can also get old, with the number of remaining healthy ones running out before the cells in the foetus start making new ones. If this happens, the embryo will run out of energy, resulting in an early pregnancy loss, failure of the embryo to implant, or failure of the fertilized egg to divide properly.

Causes

Often no cause can be found for a miscarriage. This often leaves the mother confused and worried about the next pregnancy. Having one miscarriage does not mean you are at increased risk of having another one, however if you have had 2 or more it is worthwhile seeking some advice regarding possible tests that can be done. While only two thirds of couples find a reason for their miscarriages, some possibilities include:

Increasing maternal and paternal age – both sperm and egg DNA, and egg mitochondrial DNA can become ‘fragile’ with age, resulting in an increased risk of miscarriage.

Parental genetic problem – one partner may carry a chromosomal abnormality that gets passed down to the foetus.

Uterine abnormalities – structural problems in the uterus and fibroids may affect the capacity for the uterus to carry a pregnancy. Poor endometrial development may also be implicated in failure of an embryo to implant.

Hormonal imbalances – Luteal phase deficiency associated with progesterone deficiency, PCOS and insulin resistance, low thyroid function and diabetes can increase the risk of miscarriage.

Immune factors – immune factors that affect the acceptance of an embryo can be implicated in miscarriage.

Blood clotting problems – an increased risk of developing blood clots in the placenta’s blood vessels increases the risk of a miscarriage.

Infection – certain infections, including silent genitourinary microbes, can affect a pregnancy.

Male factor – sperm quality, in particular the DNA stability, can affect the quality of a conception and thus miscarriage risk.

Lifestyle factors - are important to consider for both prospective father and mother. Cigarette, alcohol and caffeine consumption are risk factors, as are one or both parents being obese.

Nutritional factors – nutrient deficiency can contribute to miscarriage risk. A deficiency in key nutrients such as vitamin B12, folate and the antioxidant selenium, has been associated with miscarriage risk. Oxidative stress has been implicated in both infertility and miscarriage. Improving general nutrition and ensuring good antioxidant nutrient levels may help support a healthy pregnancy.

Contacts and links

Miscarriage is usually an unexpected shock. It may also indicate a need for tests to ensure you are given the ‘OK’ to embark on another pregnancy. It is important that you seek advice and necessary emotional support from your GP, gynaecologist/obstetrician, counsellor or other healthcare professional. Some useful contacts are outlined below:

Bonnie Babes provides 24 hour, 7 day per week counselling for families that have experienced the loss of a baby through miscarriage, stillbirth or prematurity and related issues such as infertility.

www.bbf.org.au
Phone: (03) 9803 1800

SANDS is a volunteer organization that can provide grief counselling for individuals or families who lose a child through miscarriage, stillbirth or neonatal death

www.sands.org.au
Victoria (03) 9899 0218
SA (08) 8277 0304
QLD (07) 3254 3422
TAS (03) 9517 4470

Miscarriage management clinic provides a program for couples living in Sydney who have experienced recurrent pregnancy loss.
www.miscarriage.com.au