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Miscarriage medical reasons why it happens and how to cope

Miscarriage is a devastating occurrence. Many women have miscarriages; often it could be the case that you may have work colleagues or acquaintances who have recently suffered a miscarriage, but they haven’t told you about it. It can be very hard for you to talk about, as the grief can be so extreme, that it’s a very painful situation to share. 

Many women will only tell those very close to them about their miscarriage. You may even feel guilty about having a miscarriage, but you shouldn’t. In the majority of cases, there will be a medical reason for miscarriage, and sadly it is often nature just taking its course.n the module Advanced settings.

some statistics

75% of miscarriages happen in the first trimester


What can make a miscarriage even more difficult, is that it is frequently the case that it is not possible to identify the underlying cause. This lack of closure can add to the trauma you have experienced. Plenty of women suffer miscarriages and go on to have a healthy baby in a later pregnancy.

75% of miscarriages occur in the first trimester, which is during the first three months. When this is the case the cause is normally related to the fetus; your unborn baby. A miscarriage that happens during this time normally means that unfortunately, your unborn baby wasn’t developing as he or she should have, and nature needs to take its course.

Miscarriage in the second trimester (14 to 26 weeks) is more often the result of an underlying health problem that you may have. It may have been that your baby caught an infection, which results in the sac of waters breaking before you start to feel pain or begin to bleed. In unusual cases, a second-trimester miscarriage can be caused by the womb opening too early.


Miscarriages during the first trimester

A first-trimester miscarriage is most often due to chromosonal problems of your fetus.

Issues with chromosomes

Chromosomes are basically blocks of DNA. Estimates show that two-thirds of first trimester miscarriages take place because of chromosome problems. In most cases, this doesn’t indicate that there are actual chromosomal issues with either you or your partners, and generally, there is a low chance that this type of miscarriage will re-occur.

These DNA blocks, chromosomes, contain complex instructions and they are in control of many factors. Chromosomes control issues such as what colour your baby’s eyes will be, through to how baby’s cells develop. It can happen that something doesn’t happen correctly at the moment of conception so that the fetus receives either too many or too little chromosomes. Although the reasons for why this happens are not clear, it sadly means that the baby will not be able to develop normally, which will result in a miscarriage.

Here you can discover a number of studies focused on miscarriages and chromosomal problems

Placental problems

Another way that miscarriage can occur during the first trimester is when there are placental problems. The placenta is an organ which plays the role of linking your blood supply to that of your developing fetus. However, if something goes wrong with this lifegiving link, this can also result in miscarriage.

Early miscarriages: what can increase your risk

Age can increase the chance of an early miscarriage. Below are the statistics.

Under 30: 10% of pregnancies end in miscarriage

From 30 to 35: 15% of pregnancies end in miscarriage

From 35 to 39: 20% of pregnancies end in miscarriage

From 40 to 45: 25-30 % of pregnancies end in miscarriage

Over 45: Over 50% of pregnancies end in miscarriage

Non-age related risk factors

Regardless of what age you are there are other factors which can increase your risk of miscarriage.


Smoking in pregnancy

Drug misuse in pregnancy

Drinking alcohol in pregnancy – there is an ongoing debate about how much if any alcohol you can consume during pregnancy. For many women, it feels natural to avoid it altogether. However, if you do take an occasional drink when pregnant, you shouldn’t take more than two units per week. A unit is a glass (half pint) of normal strength lager or bitter, or a spirit of 25ml. 1.5 units of alcohol is a glass of wine of 125ml.

To educate yourself further on this risk, you can check the following studies on alcohol miscarriage risk

Drinking over 200mg of caffeine per day – a mug of instant coffee has around 100mg of caffeine, whereas a mug of tea contains approximately 75mg of caffeine. Caffeine is also present in chocolate, some energy drinks and fizzy drinks.

Recurrent miscarriages

Previous miscarriage increases your risk slightly at an average statistic of 25%. However, remember that this an average statistic and for many women, a miscarriage is a one-off occurrence. It is estimated that 10% of women experience recurrent miscarriages, which is considered to be three or more in a row. 60% of these women do actually go on to have a viable, successful pregnancy.

A 2016 study found that a reduced amount of stem cells in the uterine lining could be the cause of recurrent miscarriages, you can read more about that here

Second trimester miscarriages

There are a number of long-term health conditions which can increase your risk of miscarriage in the second trimester.

  • Diabetes when it is not properly controlled
  • Kidney disease
  • Lupus
  • Thyroid problems – either underactive or overactive

Food poisoning

Food poisoning can increase your risk of miscarriage. This can occur if you eat contaminated food, or food that has been undercooked, or is raw. Listeriosis is food poisoning that is associated with unpasteurised dairy products. Toxoplasmosis can be caused by eating raw or undercooked meat, which is infected, especially pork, lamb and venison. Toxoplasmosis can also be caught by handling your cat’s litter box. Salmonella is commonly caused by eating partially cooked or raw eggs.


Medicines that may cause miscarriage

Regardless of what you read online or offline, always check with your doctor if a medication is safe to take during pregnancy.

Here are some of the main medicines that are known to increase your risk:

Ibruprofen family of medicines, which are known as NSAIDs, which means non-steroidal anti-inflammatory drugs. These are used to treat inflammation and pain.

Retinoids – which are used to treat acne and eczema.

Misoprostol and methotrexate – which are used to treat complaints like rheumatoid arthritis



Infections which can result in miscarriage

  • Bacterial vaginosis
  • Chlamydia
  • Cytomegalovirus
  • HIV
  • Gonorrhoea
  • Malaria
  • Rubella (german measles)
  • Syphilis

Womb structure abnormalities and issues

Second and third-trimester miscarriages can be caused by womb abnormalities and issues. An abnormally shaped womb can result in miscarriage. Also if you have a weak cervix, this can be another factor. This may happen because of a previous injury, or it may be that the muscles are naturally weaker than average. This is also referred to as cervical incompetence. Some women have fibroids in their wombs, which are non-cancerous growths. These can also be a contributing factor to miscarriage.

Polycystic ovary syndrome is when your ovaries are larger than average. It is a leading cause of infertility also, as it results in lower egg production. It happens due to hormonal changes in your ovaries. Although there is a certain amount of evidence that suggests it can be linked to miscarriage in some cases, many women with PCOS have healthy pregnancies.

Womb structure abnormalities and issues

Miscarriage is not caused by

Having sex

Your emotional state

A shock

Straining or lifting

Eating spicy food

Exercise that is suitable during pregnancy (you should confirm this with your doctor or midwife) Learn more about exercise in pregnancy by reading these studies

Working unless in some type of unsafe environment

Miscarriage emotions and support

After a miscarriage, you will possibly suffer a roller coaster of emotions. These can be so intense that they can also lead to physical reactions also. Many women are numbed by their miscarriage. Even when it is a very early miscarriage, this can happen. This is entirely natural because the bond that was there was such a special one, so you shouldn’t feel strange about this. You may feel depressed, sad, angry and be in disbelief.

It can be difficult to concentrate on normal life. In fact, it can seem almost as if normal life shouldn’t be continuing at all. In this sense, the grief is no different from losing a close loved one. The main difference is that your unborn baby was actually developing inside your body, so it is a different and very deep bond. You may find it difficult to sleep and you could lose your appetite. Unfortunately, the hormonal changes that happen after a miscarriage can make all of this even more intense.

Depending on how you are as a person, you may also find it difficult that miscarriage is not spoken about as openly as the death of a family member or close friend. This can be challenging.


Phases you may experience after a miscarriage

Phase 1: Shock and denial

The shock of a miscarriage is very intense. This may be mixed with feelings of denial also, as it is very hard to accept the loss.

Phase 2: Depression, anger and guilt

The rollercoaster of feelings can vary between or encompass all of the feelings of depression, anger and guilt. Sadly this is a normal part of the process.

Phase 3: Acceptance

At some stage, you will reach a place of acceptance. A time will come when you feel you can accept your loss. However, this is not to say that feelings from phase 2 will have entirely gone away.

For each woman, it will be different, although these types of feelings are common to most of us. Although it may not feel like it at this time, you will at some stage feel enough acceptance and have passed all of these feelings sufficiently for life to seem “normal” once again.


Miscarriage support

You will need support at this time. Turn to those that you trust and confide in them. You can also get support from the Irish Miscarriage Association, here is a link to their phone support

Each woman is different and will have different ideas as to how she would like to remember her baby. The Irish Miscarriage Association also has some ideas about Miscarriage and Remembering Your Baby

If you have suffered a miscarriage, you can download this informative booklet by the Irish Miscarriage Association

Miscarriage Diagnosis Guidelines FAQs

How can I be assured that my miscarriage diagnosis on scan was accurate?

Merrion Fetal Health follows the guidelines of The National Maternity Hospital and the Royal College of Obstetricians & Gynaecologists to ensure that misdiagnosis does not occur. These guidelines err on the side of caution and outline strict criteria for making the diagnosis of miscarriage.

What are these criteria to make a diagnosis of miscarriage?

The guidelines run to 18 pages and make many recommendations but broadly speaking an ultrasound should be carried out by appropriately trained personnel with appropriate ultrasound equipment (including transvaginal probes). In many cases, a fetus/embryo with a regular heartbeat will be identified in a healthy pregnancy sac within the womb. The ultrasound allows measurement of the size of the fetus and the sac to determine how far the pregnancy is. Sadly, it is often the case that we identify an embryo/fetus in a pregnancy sac but cannot see a heartbeat and this may mean the pregnancy is too early or not viable.

Because of the difficulties in seeing a heartbeat in very early pregnancies, there are strict criteria which we follow to ensure that we do not diagnose a miscarriage in what could be a healthy but very early pregnancy where it is not possible to see the heartbeat yet. Thus, if the pregnancy sac is less than 20mm in size or if the size of the embryo/fetus is less than 6mm and a heartbeat cannot be seen, a definitive diagnosis cannot be made and the scan should be repeated in 7 to 10 days time.

Why is it necessary to sometimes perform an internal (transvaginal) scan?

An internal scan allows better visualisation of the womb and its contents. This is because the soundwaves do not have to travel far because the tip of the probe is inserted very close to the womb and gives a much better picture than an abdominal (transabdominal) scan. With this approach, the soundwaves have to travel through your tummy wall and occasionally the images obtained are not clear enough to make a definitive diagnosis. Thus, in very early pregnancy, in overweight women or when the womb is tilted backwards, or when a clear diagnosis cannot be reached with a transabdominal scan, a transvaginal approach might be necessary.

I have been told I have a miscarriage, but I still feel pregnant. What does this mean?

This is a very common scenario because the hormones that are released by an early pregnancy that is failing can still cause pregnancy symptoms.

I have been told I have a miscarriage, but my pregnancy test is still positive. What does this mean?

Again, the hormones that are released in early pregnancy can give a positive pregnancy test. These hormones can stay in the blood for some time after the pregnancy has failed and will give a positive pregnancy test as these hormones are released into the urine which then gives a positive pregnancy test. This can occur for up to 3 weeks following any type of miscarriage.

Why was I not offered a second scan?

It is very often unnecessary to do this as the first scan diagnosis can be definite if the above criteria can be met. If there are any doubts about diagnosis a second scan will be performed, sometimes on the same day, but more often 7 – 10 days later. Some women miscarry completely and the womb or uterus will appear empty when scanned. In this case, no follow up procedure will be necessary.

What are the limitations of ultrasound?

Occasionally, ultrasound in early pregnancy may be inconclusive if the gestation is too early, particularly if you are less than 7 weeks or if you are unsure of your dates. This is because the pregnancy may be too small to be seen before 7 weeks. In order to be absolutely accurate in the diagnosis of early pregnancy before 7-8 weeks, it is recommended by all best practice guidelines, to repeat the scan after an interval of at least a week, if there is uncertainty or doubt.

What is the earliest you can diagnose a miscarriage?

All bleeding that occurs in the early weeks of pregnancy is referred to as a threatened miscarriage. Viability is uncertain in about 10% of pregnancies. Under 7 weeks a diagnosis can be difficult. When a miscarriage is suspected, an ultrasound scan is carried out to establish what the likely outcome will be. If it is confirmed that the pregnancy is not continuing, the scan findings will suggest whether there is a need for further treatment. Some women miscarry completely and the womb or uterus will appear empty when scanned. In this case, no follow up procedure will be necessary.

What happens if a miscarriage is diagnosed?

There are various treatment options which would include awaiting for a spontaneous miscarriage which usually involves heavy bleeding, similar to a heavy period. This approach might be recommended if there is a small amount of tissue in the womb. An alternative treatment would be to use a medication called Cytotec which might induce a miscarriage and is also used prior to ERPC/D&C. If there is a big pregnancy sac and/or a lot of tissue in the womb the usual recommendation will be to undergo an ERPC/D&C.

What is an ERPC? (also called a D&C)

ERPC stands for Evacuation of Retained Products of Conception and is a procedure performed under general anaesthetic that involves removing the remaining blood clots and pregnancy sac from the womb in order to stop further bleeding. Although instruments are passed into the womb no actual surgery takes place and no stitches are needed.

What happens if I decline an ERPC/D&C?

If you decline to have an ERPC (D&C) this will be your decision. The benefits and risks of the above treatment options will be discussed with you so that your decision is informed. Occasionally miscarriage can be accompanied by very heavy bleeding, necessitating blood transfusion and may pose risks to your overall health and well being. The other reason for suggesting an ERPC is if pregnancy tissue remains in the uterus (womb) this can lead to infection which occasionally can be serious.

What is an ectopic pregnancy – does this not mean I am still pregnant?

This is when the pregnancy implants and grows outside the womb, usually in the fallopian tubes or occasionally the ovary. The symptoms usually include acute pain and slight bleeding. A scan is normally performed to assess whether this suspected diagnosis is correct. An ectopic pregnancy is a serious complication and it is not possible to save the pregnancy. Surgery is usually required but sometimes medication can resolve this. More information here by clicking on ectopic pregnancy.

Are all scanning staff appropriately qualified in Merrion Ultrasound?

The sonographers and obstetricians in Merrion Ultrasound are all highly qualified in scanning and are very experienced. You can meet some of our sonographer team here.


Nuchal Translucency

12-14 weeks


Anatomy Survey

20-22 weeks


Later Dating

10-17 weeks


Gender Scan

19 weeks onwards


Growth & Well Being

22 weeks onwards


Post Dates & Liquor

40 weeks onwards


What Our Patients Say

Gráinne Macken

This is my second visit to Merrion Fetal, I was very pleased on both occasions. Lovely quiet waiting room, appointment was on time. The 20-week scan is very detailed we enjoyed watching our baby on the large TV screen. We got some beautiful photos. The nurse was very pleasant and talked us through all the measurements and anatomy. I would highly recommend this scanning clinic.”

Áine Gibney

I had the best experience at the Merrion Fetal Health clinic for my 20-week big scan. The staff were so friendly and so nice and the lovely lady who did my ultrasound scan was amazing. She was so thoroughgoing to absolutely everything and gave me such reassurance on how my baby was growing and developing. I would recommend any Mother to be to attend here if you are looking for a comfortable, reassuring and super pleasant experience.”

Linda O'Sullivan

Highly recommend! We had an early scan due to a little scare at the start of pregnancy and then another at 12 weeks to make sure all was good again. Helen who was scanning on both days was fantastic. We felt totally relaxed and un-rushed while she took her time finding the best angle of baby to get us the clearest pictures as keepsakes all while making sure everything was perfect with baby. She reassured us throughout and I can honestly say it was the best money we ever spent getting both scans done.

Please let Helen know we are 18 weeks now and flying along Highly recommend!



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