Miscarriage is the loss of baby during the earlier weeks of pregnancy and is something that affects many women, their partners (if there is one), older siblings, family and friends. Losing a baby through miscarriage is a heartbreaking experience, no matter how early in the pregnancy it happens, usually rousing deep feelings and emotional reactions.
In Australia, miscarriage is defined as a baby who dies before 20 weeks gestation and/or less than 400 grams in birth weight. Babies who die after 20 weeks gestation (or who weigh more than 400 grams) are classified as being stillborn. This definition is not applied worldwide. The World Health Organisation (WHO) defines miscarriage as being up to 23 weeks of the pregnancy and 500 grams in weight, and other countries will define miscarriage as up until 24, 26 or 28 weeks of pregnancy. The definition of a miscarriage is also usually divided up into ‘early miscarriages’ (before 13 weeks) or ‘late miscarriages’ (after 13 weeks and before 20 weeks). About 80% of miscarriages will occur before 12 weeks.
The risk of miscarriage is highest immediately after implantation. It is thought that around 50% of all fertilised eggs do not survive, coming away with a normal (or slightly late) period. This is often referred to as an ‘unnoticed miscarriage’ because it is usually not formally acknowledged by the woman, who is never aware of her pregnancy.
It is estimated that about 15 to 20% of known pregnancies will end in miscarriage. This statistic is often received with surprise and shock, equally because of its high prevalence as well as how little it is acknowledged and talked about openly. While a miscarriage can happen at any time during the first 20 weeks of pregnancy, they more commonly occur around the times the woman’s subsequent periods would have been due.
Women who experience one miscarriage are not more likely to experience another (unless they have a medical condition that is likely to cause recurrent miscarriages). Up to 97% of women who experience one miscarriage will go on to have a healthy baby with a subsequent pregnancy and up to 75% of women who have had 3 or more miscarriages will have a subsequent normal pregnancy and baby
Reasons for miscarriage
During the first 12 weeks of pregnancy an intricate and complicated process takes place as the woman’s egg is fertilised and the baby implants, develops and grows. It is thought that up to 50% of miscarriages are due to a spontaneous genetic or structural abnormality in the baby, with most of these occurring at the time of fertilisation. This can cause the new baby not to develop properly, or to die after only a few weeks of the pregnancy. If the baby does not continue to thrive and grow, in most cases the woman’s body will naturally expel the baby through miscarriage. It is for this reason that many people believe miscarriage to be ‘Nature’s way’ of ending a pregnancy that would otherwise have led to a baby being born with major abnormalities.
Although miscarriage is very common, for the majority of women the cause of their miscarriage will remain unknown. Even with the many advances in medical technology in recent decades, there is still much we do not know about the loss of a baby through miscarriage. This lack of information and ‘not knowing’ why your miscarriage has occurred can make dealing with it very difficult. The question of “Why me?’ will often bring up feelings of frustration, helplessness, guilt and doubt about your body’s ability to carry a baby, as well as much fear and anxiety about future pregnancies.
If the miscarriage cause remains unknown, it is important to remember that it is very rare for a woman to miscarry because of something she may or may not have done. This can be hard to accept when coming to terms with losing your baby, because it is very common for women to search for reasons as to why they may have miscarried. Feelings of guilt can be reinforced by friends or relatives suggesting a ‘reason’ for your miscarriage. (Probably based more on myth and folklore, rather than a real medical cause.)
Guilt and self-blame are very common reactions to miscarriage. These will often be felt no matter how much caregivers try to reassure you that your actions (or inactions) were not responsible for you losing your baby. Many thoughts can cross your mind, “Was it because I did not rest enough, or had that glass of wine, or had a cold, or was working too hard or didn’t start my folic acid tablets? Did I cause this miscarriage?’ These feelings are distressing, but a very normal part of the grief and loss.
There are a few known medical causes of miscarriage. This can account for a further small percentage of miscarriages, as well as the cause of some recurrent miscarriages (where the woman experiences 3 or more miscarriages in a row). Occasionally, tests can be done to determine a medical cause, but in the majority of cases no cause will be found.
The following are a list of some possible medical causes for miscarriage that may explain for a few women why their miscarriage has happened. Identifying a reason (if this is possible) can often help you come to terms with it better, because it may work towards assisting you in avoiding another miscarriage in the future. Medical reasons may include:
An infection of the uterus during early pregnancy.
Other viral or bacterial infections during early pregnancy, such as rubella and Listeria
Medical interventions to detect abnormalities in the baby. A CVS (done between 10 to 12 weeks) or an amniocentesis, (done between 14 to 18 weeks) can increase a woman’s risk of miscarrying her baby.
A weakened cervix that can allow the cervical muscle to spontaneously open, usually between 14 and 28 weeks of the pregnancy. This is known medically as ‘cervical incompetence’ and in some cases is treated with a‘stitch in the cervix’.
If the baby implants on an area of the uterus where there is a very large fibroid, the blood supply may be diminished to the baby and unable to support their continued growth.
Trauma (such as a serious car accident), or a blow to the woman’s lower stomach.
If the woman needs abdominal surgery during the first 20 weeks of pregnancy.
An unusual shaped uterus. A few women are born with this, increasing their chances of miscarriage after 12 weeks of the pregnancy.
Environmental exposures to certain drugs or prescribed medications, smoking, excessive alcohol, radiation, certain chemicals and pesticides.
Health conditions such as autoimmune diseases (for example Lupus), blood clotting disorders, diabetes, hormonal imbalances, kidney disease or low thyroid function. These may be the reasons for ‘recurrent’ miscarriages, meaning 3 or more consecutive miscarriages. However, when some of these conditions are treated or well controlled, the chances of miscarriage will tend to be no greater than any other healthy woman.
Increased age. The incidence of genetic abnormalities increases with the woman’s age. Miscarriage rates are about 10% for women in their 20’s and up to 50% for women over 40. There is also some recent research that implicates a man’s increased age as also being a possible factor for miscarriage.
The loss of a pregnancy can come as a terrible blow. As well as the emotional shock for you and your loved ones, you may find the physical symptoms hard to bear.
Here, you’ll find information about all stages of pregnancy loss, the possible causes, and advice about how to take the first steps towards recovery.
What is a miscarriage?
A miscarriage is the loss of a baby before 20 weeks of pregnancy (RWH 2011). If the loss is experienced in the first 12-14 weeks of pregnancy it is called an early miscarriage. If the loss happens after this, it is called a late miscarriage. Definitions may differ depending on your hospital or caregiver.
How common is miscarriage?
It depends when it happens. Sadly, early miscarriages are very common. Often, a woman miscarries before she even realises she’s pregnant. Perhaps as many as three-quarters of all fertilised eggs are lost in the very earliest days of pregnancy. After a positive pregnancy test, there’s about a one in five chance of having an early miscarriage (RCOG 2008a, 2006a). This is when most miscarriages happen (Symonds 2009:314).
Late miscarriage is much less common (RCOG 2006a:2). It happens in about one in 100 pregnancies (Symonds 2009:314). Late pregnancy loss can be very hard to bear. At this stage, for many parents, the term “miscarriage” doesn’t do justice to the depth of sorrow they feel at losing their baby.
Some women experience the anguish of recurrent miscarriage. This means that they have three or more miscarriages in a row. This happens to about one woman in 100 (RCOG 2003:1).
What causes a miscarriage?
Early pregnancy loss usually happens because the embryo is not developing as it should. Chromosome problems are thought to be the most common cause (RCOG 2008a). These problems usually happen for no obvious reason.
To develop properly, a baby needs the right number of normal chromosomes. He’ll need 23 from his mother and 23 from his father. Chromosomal abnormalities can prevent a baby from developing. These abnormalities may happen because there are the wrong number of chromosomes, or because there are changes to a chromosome’s structure. In that case, the pregnancy ends at the embryo stage.
Late miscarriages are more likely to be because of a health problem in the woman rather than the baby (NHS Choices 2009), but this is not always the case.
If you have several miscarriages in a row, you may be desperate to know why this is happening to you. Sadly, in many cases, a cause simply cannot be found (RCOG 2004, RCOG 2003). You can take hope from the fact that three out of every four women who’ve had unexplained recurrent miscarriage go on to have a healthy baby.
How do I know if I’m at risk?
It’s hard to say who’s at risk. Often, pregnancy loss happens for no reason and there is nothing that can be done to prevent it. This is especially the case with early miscarriage. The fact is that many women who have miscarriages are perfectly healthy.
Bearing all that in mind, we do know of some factors that may increase the risk of miscarriage:
The older you are, the more likely it is that your developing baby will have a chromosomal abnormality. At 30, your risk of miscarriage is one in five. At 42, your risk is one in two (RCOG 2008a).
If you have problems with your health, it’s important to get the right care. Being overweight, having a poorly controlled condition, such as diabetes or a thyroid problem, can increase the chances of miscarriage.
Sticky blood syndrome, or antiphospholipid syndrome (APS), which causes blood clots to form in blood vessels, is known to cause recurrent miscarriage. APS, which is also known as Hughes syndrome, can be a problem on its own or can happen alongside lupus. APS is treatable.
Some abnormalities of the uterus may make miscarriage more likely.
Infections can cause miscarriage if you catch them while you’re pregnant. These include listeriosis and toxoplasmosis. Sexually transmitted infections, such as syphilis, and conditions that affect your hormones, such as polycystic ovaries, are also linked to late pregnancy loss.
We know that smoking, heavy drinking (RCOG 2008a, 2006b:4) and taking cocaine (OTIS 2008) mean you have a higher chance of miscarrying. Having too muchcaffeine in your diet may also increase this risk (FSA nd). Bear in mind, though, that you can safely have 200mcg caffeine a day (approximately two mugs of instant coffee or one small cup from a cafe) (NSW FA n.d.).
Which old wives’ tales are just old wives’ tales?
There are plenty of old wives’ tales about miscarriage, particularly when it comes to possible reasons why you’ve lost your baby. They can cause you a great deal of anxiety or guilt if you believe them.
Two common ones are that miscarriage can be caused by having sex while you’re pregnant or stress. There is no evidence that either having sex or getting stressed causes miscarriage (NHS Choices 2009, RCOG 2006a).
It’s also quite safe to start or continue to exercise gently in pregnancy. It’s good for your general health, anyway. Just be sure to avoid any high-impact sports that could result in you falling or taking a blow to your tummy (NCCWCH 2008:94-5).
How do I know if I’m having a miscarriage?
The most obvious signs are period-like pains and heavy bleeding, which may include blood clots. However, you can miscarry without knowing, especially early in pregnancy. Many women mistake a miscarriage for a late period.
Some miscarriages are discovered only during a routine early pregnancy scan when ultrasound reveals an empty pregnancy sac, where the embryo should be. This is sometimes called a missed miscarriage (RCOG 2008, RCOG 2006a:2). You may have had no idea that this has happened, in which case it will come as a terrible shock. Or you may have had some symptoms, giving you a growing fear that all was not well.
Sometimes, the levels of pregnancy hormones drop enough for you to notice that you’re feeling less nauseous or your breasts are feeling less tender. Remember, though, that it’s natural for these pregnancy symptoms to go away after 12 or 13 weeks.
A late miscarriage is a particularly difficult experience to go through. The signs of late miscarriage are heavy bleeding, and, sometimes, your waters breaking. This may be accompanied by intense, labour-like pains, for which you need pain relief. There isn’t always pain, though. Pregnancy loss because of a weak cervix may be painless.
I’ve had some spotting. Is it a problem?
Spotting means losing very small amounts of blood. You may notice spots of blood on your underwear or when you use toilet paper. Spotting in early pregnancy is very common and in many cases turns out to be nothing to worry about.
However, with any bleeding, you should ring your doctor or midwife (RCOG 2008b). Depending on your symptoms, you may need to be checked straight away or be asked to go to antenatal clinic or in some areas an early pregnancy assessment unit the next day. If the bleeding stops and your pregnancy continues, it is known as a threatened miscarriage.
I can’t seem to get over my miscarriage. Where can I get help?
Coping with a miscarriage can be a heartbreaking experience. Losing a baby is tragic no matter how early in pregnancy it happens. You will need to allow yourself a chance to grieve. Your partner will need time to come to terms with the loss, too. Every person’s experience of bereavement is different, so give yourself plenty of time to recover.
In time, you will be able to look to the future again. When you’re ready to think about trying again, it may be some comfort to know that most women go on to have a healthy baby in the future (NHS Choices 2009).