By fertility experts from Spain.
What could be the cause of repeated miscarriages? Is it normal to miscarry twice in a row? How can I prevent repeated miscarriages? Is IVF treatment a solution for me? Miscarriage is more common than we might think. It affects women at any age, those under 20 and those over 30. Finding a cause of miscarriage is not always easy but… To help you get some answers to the above questions, we invited Dr Ahmet Ozyigit, Ph.D., Assistant Professor at North Cyprus IVF to speak on the topic of repeated miscarriages and their possible causes.
Dr Ahmet Ozyigit is a clinical embryologist with over a decade of experience in assisting patients with fertility treatments. Dr Ozyigit, who is also currently finishing up his MD degree, comes from an eclectic background with 2 Bachelor’s Degrees, 2 Master’s Degrees, and Ph.D. degrees in different fields. His passion for education and research is the foundation for his career as a physician, embryologist, researcher, and clinic manager. He currently holds a teaching position at the Mediterranean University of Karpasia and is the lead for clinical research at North Cyprus IVF Center. Watch the above video recording of our LIVE event with dr. Ahmet and the Q&A session with patients.
Dr Ahmet Ozyigit starts by highlighting that medicine is a very dynamic field of science. It practically changes every day. It happens that what we know one day may be refuted the next day. So even though this webinar going to cover a lot of reasons for repeated miscarriages, it is not a comprehensive list and (like any other webinar!) It should never replace a consultation with a doctor.
Dr Ozyigit goes on to explain what a miscarriage is. By definition, it is a loss of pregnancy before 20 weeks of gestation. After 20 weeks, it is called a stillbirth. Broadly speaking, there are three main types of miscarriages: complete miscarriage, incomplete miscarriage and missed miscarriage. A complete miscarriage is when all the pregnancy tissue has left the uterus. Once it happens, it is common to have vaginal bleeding, cramps and contraction pains. A complete miscarriage occurs before 12 weeks of gestation. An incomplete miscarriage, on the other hand, happens after 12 weeks of gestation. It is when some of the pregnancy tissue still remains in the cervical canal. Such type of miscarriage results in cramps and vaginal bleeding, too. When it comes to incomplete miscarriage, it is often advisable to use some medications or D&C (dilation and curettage) in cases where the pregnancy tissue does not pass on its own. Finally, the third type of pregnancy loss is called a missed pregnancy (or missed abortion). As contrary to the previous two, it is often silent – meaning there are no cramps, pain or bleeding. Although the fetal activity is stopped, the fetus does not leave the uterus and the cervix is closed. This type of miscarriage is often diagnosed at the 12- or 20-week scan.
Dr Ozyigit admits that, traditionally, the term ‘recurrent miscarriages’ was used where three or more consecutive pregnancy losses were experienced. However, the likelihood of a third pregnancy loss after a second one has been estimated as 30% while the likelihood of a fourth pregnancy loss (after a third one) has been estimated as 34%. This means that a thorough investigation is warranted after the second miscarriage – also, in order to spare a patient the devastating effects of another such stressful and traumatic experience. An investigation is not perceived as necessary in case of a single miscarriage as more than 90% of the women will go on to have a problem-free pregnancy after a first miscarriage.
When investigating pregnancy loss, doctors have to consider the time frame during pregnancy in which the pregnancy loss is experienced. Similarly, the mother’s age is very important. According to the Royal College of Obstetricians and Gynaecologists (RCOG), approximately half of all pregnancies will result in a miscarriage when the biological mother is over 40 years old.
In the case of two or more consecutive miscarriages, the possible causes may be very different. A high percentage of them (around 40-50%) are classified as unknown. It means there are still things that doctors are not able to identify. Fortunately, the rest of the causes is possible to be defined, analysed and – hopefully – successfully dealt with.
Dr. Ozyigit states that genetic causes constitute around 2-5% of all repeated miscarriages. But although it is just a small percentage, it is one of relatively less invasive and easily identifiable reasons – e.g. through a blood test or a chromosomal karyotype analysis. Chromosomal abnormalities can be classified as numerical or structural. The numerical abnormalities (meaning less or more chromosomes) are generally associated with the inability to conceive, whereas the structural ones (such as e.g. chromosomal deletions, duplications or translocations) are linked to both the inability to conceive and recurrent pregnancy losses.
Parental aneuploidy (meaning an abnormal number of chromosomes) accounts for approximately 2-5% of all miscarriages. However, up to half of the miscarriages are associated with aneuploidy in the fetus. These are the translocations (either reciprocal or Robertsonian) that are the most common cause resulting in a pregnancy loss. Translocations (and other parental chromosome abnormalities) can be revealed through a karyotype testing for both the intended mother and the father. Dr Ozyigit says that once doctors see the karyotype analysis, they follow with an IVF procedure that includes PGS (preimplantation genetic screening) on the embryos. In this way, only the chromosomally normal embryos are picked for the transfer and the chances for another miscarriage are reduced.
Dr Ozyigit then goes on to explain anatomical and structural abnormalities that have to do with either the cervix or the uterus. Cervical incompetence (or cervical insufficiency) is known as a structural cause of pregnancy loss. The cervix normally stays closed and firm throughout the course of pregnancy. Only until shortly before the onset of the labor, certain hormones cause it to soften. However, incompetent cervix will fail to remain closed. Cervical incompetence is often the cause of a miscarriage in the second trimester. Most anatomical causes, on the other hand, are congenital – it means they are present at birth but tend to go unnoticed until later in adulthood. During embryological development, most of the female reproductive tract is formed from the fusion of structures called the müllerian ducts. If they fail to fuse, they can interfere with the development of normal uterine vasculature and disrupt the blood supply to the endometrium. Another congenital transformation that can prevent a pregnancy from progressing is a septate uterus.
The third group of miscarriage causes is immunological disorders. In fact, more and more fertility issues might have to do with immunology. The human immune system is designed to defend the human body against foreign threats. Both an overactive and an underactive immune system may lead to infertility problems. Although the embryo is perceived as a foreign object, there are ten different mechanisms that are believed to prevent the mother’s immune system from being too active against it.
Dr Ozyigit differentiates between autoimmune and cell-mediated responses associated with miscarriages. The autoimmune conditions that could interfere with a successful pregnancy are organ-specific antibodies (e.g. antiphospholipid, anticardiolipin, antinuclear or anti-histone antibodies). According to dr. Ozyigit, even though you don’t show signs of autoimmune disorders, it doesn’t mean that you don’t have the antibodies for them. That’s why it makes sense to test for these antibodies. Cell-mediated immune responses (at the local and systemic level) can be identified by measuring cellular activity. Natural Killer cells can also be associated with recurrent miscarriages.
A large portion of miscarriages are also caused by thrombophilia disorders. They are relatively easier to test – the tests are less costly and more widely available than 10-15 years ago. Thrombophilia is a condition known as a blood-clotting disorder. Women with thrombophilic disorders can develop blood clots throughout the body, including at the site of embryo implantation. Blood clots can also travel into the placental circulation and stop a fetus’s heart. Inherited thrombophilic disorders are caused by a variety of mutations and deficiencies in certain genes or gene products, such as a deficiency of natural anticoagulants.
When discussing potential causes of miscarriages, one also has to take infectious diseases into account. The most common infectious agents associated with pregnancy are covered by the TORCH acronym: Toxoplasma gondii, rubella, cytomegalovirus and herpes simplex virus. However, dr. Ozyigit says that while these infections are likely to cause a single miscarriage, they’re not considered to bring about recurrent miscarriages anymore.
Finally, hormonal problems may have a serious impact on pregnancy loss. The known risk factors for miscarriages are thyroid, adrenal gland problems and diabetes. In addition, an elevated prolactin level can also disrupt the development of a normal uterine lining, thus contributing to early-term miscarriages.
Dr Ozyigit admits that although all the mentioned miscarriage causes may seem scary, doctors have different tools at their disposal that can help to reduce the likelihood of this problem. Firstly, it is important to remember that one miscarriage does not usually call for further investigation. However, after two consecutive pregnancy losses, it is advisable to begin an assessment. Dr Ozyigit says it is good to start with less invasive and less expensive tests first. Some tests, due to a number of factors (such as e.g. family history of miscarriages, relevant own medical history), may be preferred over others. The further investigation that doctors would do normally includes karyotype testing, trombophilia testing, uterine assessment as well as autoimmune and hormonal testing.
It depends what the problem is. If it has nothing to do with the clotting problem, if it is not something that could be fixed with Aspirin, then obviously Aspirin is not going to do anything. Usually, during a lot of pregnancies, Aspirin could be used. Most of the cases is not that detrimental. So especially women, who’ve experienced a number of miscarriages, do take Aspirin. The jury is still out on that. We do sometimes like to use Aspirin as well because it gives us peace of mind that we are actually doing something different as well. But in our experience, Aspirin, unless there is a reason why we should be giving it, will not fix the problem. Taking Aspirin, without knowing where the problem comes from, is not very likely to help. But it is a precautionary measure that could be taken. But if you’re looking at, for example, MTHFR mutation, PAI-1 mutation, one of thrombophilia mutations or reduced activity of protein CMS, you’re looking at a blood clotting problem that is not going away with Aspirin. It’s something that requires low-molecular-weight heparin (LMWH) injections so that you could actually take care of the clotting problems. You would probably need to take it all throughout the pregnancy if you do have a thrombophilia defect and you should be using anticoagulants.
Unfortunately, age is a very important factor. One of the things that come with age is chromosomal problems – not with the patient herself but with the baby. The higher the age of a biological mother, the more chromosomal problems we see with the offsprings. So even though everything might be perfect and the patient might not have any of the problems we talked about, just being over the age of 40 does put her at an elevated risk of chromosomal problems with the baby. And these are those chromosomal problems that are likely to cause a miscarriage rather than anything that the patient might be doing. So taking Aspirin during pregnancy is a precautionary measure here but it’s not going to eliminate the risk of the chromosomal problems with the child that come with age. Down’s syndrome is something that we see more often, as well as other chromosome aneuploidies. That’s why when you see someone over the age of 40, you do see more miscarriages. Of course, younger people do have miscarriages as well, but there is usually a reason why they do – such as the ones that we’ve talked about during this webinar. But over 40, we’re mostly looking at chromosome aneuploidies with the child. That comes with the ageing of the eggs. Every woman is born with a finite set of eggs. And these eggs do not replenish, they do not reproduce during your lifetime. They age as you age. So today your eggs are over 40 years old as well and they do start having more and more genetic problems. And the more genetic problems they have, the more chromosomal aneuploidies we see with the offsprings. So over 40, there is not much you can do in terms of the genetic aspect. Yes, you could take Aspirin to reduce further risks of other problems. But otherwise, at over 40 years of age, you’re always looking at an elevated risk of a miscarriage because of chromosomal issues.
Everything that we’ve discussed could actually happen before 12 weeks or after 12 weeks – except for the cervical incompetence. Cervical incompetence usually happens after 12 weeks because the baby starts to grow a little bit bigger. And then the cervix, being incompetent, is not able to carry it anymore so it just opens up and then the baby is lost. That of course requires certain height and certain weight of the baby. The rest of the things that we’ve discussed could happen either before 12 weeks or after 12 weeks. But if we’re talking about immunological or genetic problems, they most likely to happen before 12 weeks. We always say the same thing to our patients: 12 weeks is a milestone in a pregnancy. So once you go beyond the 12-week period and the first trimester, then we breathe a sigh of relief. After 12 weeks, the chance of pregnancy losses will go much lower. However, thrombophilia defects could happen at the time of implantation in terms of blood clots. So they could actually prevent implantation and pregnancy. Or after the pregnancy you would be looking at thrombosis going into the baby’s circulation. These are more likely to happen after 12 weeks because your placenta needs to form and the placental circulation needs to be sufficient so that this blood clot can actually travel into the baby’s heart. So going past 12 weeks does not guarantee that you’re going to have a problem-free pregnancy. However, it does eliminate the risks to a great extent.
This is a very good question. I think you are referring to Natural Killer cells because there are two alternative ways of testing for natural killer activity: one is in peripheral blood and the other – in the uterus. You can biopsy a small part from the endometrium or you could test the natural killer activity in the peripheral blood. There are several studies on this, which show that peripheral blood natural killer activity does not necessarily correlate to the natural killer cells activity in the uterus. So you could actually have a higher load of natural killer cell activity in the endometrium and that does not necessarily occur at the peripheral blood levels. So it is not so much in the circulation per se, but is more localised in the uterus and the endometrium where the baby is supposed to implant and grow. If we do suspect natural killer cells activity and if you are willing to go through the testing, we recommend the endometrium biopsy for natural killer cells activity – although it is invasive. So if you were to have a test for natural killer cell activity, I would definitely recommend the endometrium one. It is there where the elevated localised activity of Natural Killer cells might be showing. And with the peripheral blood, you’re not going to get the answers that you’re looking for.
In fact, it could help – but to a certain extent. The idea behind a cytoplasmic transfer is the fact that as women age, their eggs age, too. With cytoplasmic transfer, you’re harvesting eggs from a young and healthy egg donor and you’re injecting the cytoplasm from these eggs into the eggs of the intended mother. So you’re not doing anything with respect to the genetic material per se but you’re injecting the cytoplasm into the genetic material of the intended mother. In that way, you can provide it with a better environment. We know that the cytoplasm contains the mitochondria and the mitochondria are the powerhouses – they produce the necessary energy for cellular growth. They’re in every single cell that we have and eggs are no exception. So if you took out the cytoplasm from a healthy donor egg and put it inside the eggs of the intended mother, you would be essentially giving the genetic material of the intended mother a better chance of survival as you’d be providing it with a better source of energy. So yes, it is something that would reduce the risk of a miscarriage. But obviously a cytoplasmic transfer does not eliminate the genetic problems because you’re still using your own genetic material. And that genetic material is still ageing with the eggs – no matter how much of a better environment you’re providing it with.
There are certain things that could be done if you’re over 40 and you’re going for a natural pregnancy. Certain supplements, like e.g. antioxidants, could help you to keep the body relatively healthy. But they have very limited impacts and effects. If we’re talking about going through IVF, then there are certain things that could be done, such as screening the embryos. There is also something that we incorporate into our own clinical practice – this is the use of human growth hormone. We administer it for patients over the age of 40 who have gone through IVF before and were not able to get enough eggs or their eggs were of a low quality. It’s been shown – not only in research but also in our clinical practice – that using human growth hormone is something that does help with the genetic integrity of the eggs. It supplies eggs with the necessary growth factors and it comes in handy especially during the mitotic divisions of the eggs. We would start using them before planning the pregnancy – approximately 6 to 8/10 weeks earlier. Egg development takes about 75 days – it’s during this time when an egg would go from a primordial follicle into ovulation and all the differentiation takes place. So if you’re going do anything, you have to do something within these 75 days. If the patient has a lot of preantral follicles, then we would use the human growth hormone for around 40-45 days. But if the patient no longer has a lot of preantral follicles and we’re looking at the primordial ones, then we would recommend 10 weeks of human growth hormone. So we do use human growth hormone as a means of offering better mitotic activity and better genetic integrity for the oocytes. And it does work. Of course, it does not create miracles but quite a lot of times, I’ve seen it working where the pregnancy has failed before. It is a part of our treatment regimen in patients who are having difficulties conceiving and because of oocytes’ quality concerns.
Well, I do differentiate between PGS and PGD. Pre-implantation genetic screening (PGS) is what we use to test the embryos when there is no known cause. Pre-implantation genetic diagnosis (PGD) is used to diagnose a known problem – for example, if the intended parents have the sickle-cell trait or if there is another known genetic problem running in the family that could be passed down to the offspring. So you’re doing it for a specific purpose and you’re testing a specific gene mutation. But if we’re talking about PGS and screening out all the chromosomes, then you’re right that an abnormal embryo could still produce a normal baby – especially if there is mosaicism. There is a whole debate on what to do when you screen the embryos with PGS and you see that the embryos are mosaic. It means some of the cells have a mutation but the rest of the cells don’t have a mutation – not all the cells are the same. Most of these embryos actually go on to produce normal children without any defects. So do you transfer something that could potentially create genetic problems or do you not transfer it? Especially if someone has paid so much money, has suffered so much already and just wants to have a healthy embryo transferred – do you really want to transfer the mosaic embryo to them? Of course, that is something that needs to be discussed with the patients. But if there is a mosaic embryo, then I would prefer not to transfer it – especially if we do have other healthy embryos. I would never transfer the mosaic ones because I don’t know what’s going to happen. Of course, if you’ve done the biopsy and if you’ve found that there is a mosaic embryo that could produce a normal healthy pregnancy but you’re not transferring, then yes – you’re preventing the pregnancy from happening. But in most cases, we’re not looking at only one embryo. If we’re talking about pre-implantation genetic screening (PGS), we would want to have more embryos to test. If we believe that we’re going to get a limited number of embryos during the IVF process, we use embryo banking. We don’t proceed with testing and the embryo transfer – we just bank the embryos that we’ve created and then we offer a second IVF cycle. We just add more embryos to the batch so that in the end we have more embryos to biopsy and to screen for genetic abnormalities. If you’re doing PGS on 5-10 embryos, there’s a very high chance that you’re going to find a healthy embryo to transfer. So in case of patients who have limited ovarian reserves, a limited number of eggs and embryos, we would usually recommend going through two cycles of IVF. It would actually only minimally increase the cost of your treatments (you’re doing two treatments but at the same time) and it would give you a much higher chance of success. So PGS still works when you have a good number of embryos to test.
We still don’t know exactly the mechanism of PCOS. It could be due to the insulin resistance problem and this could be involved in other pathways as well. So yes, there is a higher tendency of PCOS to cause miscarriages – this is something that we already know. In PCOS, we’re talking about many eggs competing with each other to receive luteinizing hormones (LH) and follicle-stimulating hormones (FSH). When the brain releases these hormones, they are received by the ovaries and the ovaries respond by developing the oocytes. In a normal ovary, you would have a few eggs and they would all receive these FSH and LH hormones. Some of them would receive more than the others and then you would go into ovulation. However, with PCOS you have very many follicles in the ovaries, they’re all competing and none of them essentially receives a desirable amount of FSH and LH hormones to actually reach ovulation. This may compromise the quality of the eggs. So although we do not know what’s exactly causing the miscarriages, the quality of oocytes might be an issue. What we usually recommend to PCOS patients is myo-inositol supplementation. It does help with the oocytes quality and sometimes we do use it with poor responders as well as with women with a very limited ovarian reserve. So it is something that could be done. You are 43 years old and that is something to keep in mind, too. 43 is a very critical age when it comes to pregnancy with own eggs. However, PCOS, in fact, is something that helps in this case. If you’re 43 years old without PCOS, then we’re concerned with not being able to get enough eggs. But if you’re 43 years old with PCOS, then we would be looking at a larger pool of eggs. If we use the medication correctly and if you do it in a way to increase the quality of the eggs that we obtain after the IVF protocol, then that could be used to our advantage. With PCOS patients, folic supplements are one thing that could help with the quality of the eggs. Depending on the number and the quality of the eggs that have been observed in the previous failed IVF cycles, alternative options could also be used – such as a cytoplasmic transfer or a tandem cycle. A tandem cycle is always an option if you’re looking at low-quality eggs and poor ovarian response. But before going down that route, there are a few things that could be tried with your own eggs to help improve their quality. So myo-inositol supplementation would be one thing and also possibly human growth hormone – if we’re looking at oocytes problems.
It’s important to know which hormonal imbalance we’re talking about. If there are elevated levels of prolactin, then that’s something that we will need to correct. If there is hyperthyroidism, we would need to address the thyroid problem. If we’re looking at elevated glucose and diabetes, that’s something we would need to address, too. If we’re looking at low levels of progesterone because of something along the pathway (such as elevated prolactin or reduced levels of globulin), then in that case we would probably supplement with progesterone. In IVF pregnancies, we always supplement with progesterone anyway. When we collect the eggs from the ovaries, we collect the follicles with them. In a natural pregnancy (without IVF), after ovulation, the egg would be released from the follicle. But the follicle would still remain there and it would turn into something we call corpus luteum. The corpus luteum would be responsible for secreting estrogen and progesterone. So when you have the corpus luteum, you’re keeping the endometrium healthy and thick for the pregnancy. But if you don’t have it, meaning if you’ve undergone IVF treatment and the follicles have been harvested and disposed of, then we need to provide you with progesterone. That’s exactly why we use progesterone in IVF pregnancies – because it is not available in the body. However, after 12 weeks, the placenta will take over and start producing its progesterone so we no longer need to supplement the patient with it. So depending on which hormone we’re talking about, you need to adjust that issue so that you can actually have a healthier pregnancy.
The problem is I do not know which tests have been administered. I’m sure they’ve probably done the thrombophilia testing and I’m assuming the immunological testing has been administered as well. I’m sure the karyotype testing has also been performed because that’s one of the things that we do. Sometimes doctors may ignore the role of hormones so they may not administer the hormone testing to the extent that we would like to see. Sometimes they may skip the immune problems altogether and they may not offer that because they don’t know where to look and what to find. This is not going to be a very satisfactory answer because I don’t know your history. I don’t know your test results and I don’t know which tests have been offered. But in our IVF protocols we use antibiotics for about a week before the embryo transfer. We believe that if there is a chronic infection in the reproductive tract, then that might affect the implantation of the embryo. So that’s something we do as a precautionary measure. We use corticosteroids which do reduce the immune activities. It’s a mild immunosuppressant. About 5-6 days before and after the embryo transfer, we try to bring the immune system down a little bit so that it doesn’t try to fight with the embryo. When there is something that’s unexplained and the patient is having miscarriages and is not able to fall pregnant, you do want to make sure that you’re eliminating some of the risk factors. So these are some of the things that we do. But, at the same time, we would need to know which tests have been performed so far. Some of the things that I haven’t mentioned in the webinar, because they’re not general things, would be sperm DNA defects. DNA defects with the sperm fragmentation issues show themselves later on during the embryo development. So initially you do achieve fertilisation and pregnancy but, later on, sperm related DNA defects could show up as early-term miscarriages. That is something that we should keep in mind as well. Maybe a sperm DNA fragmentation test, if it hasn’t been offered yet, could be done. But otherwise, I would like to see the test results. Then I could let you know which tests haven’t been performed or, if they have all been performed, I could suggest some precautionary measures that could be taken.
We do have a couple of things that are problematic here: a number of mutations with thrombophilia defects and the Natural Killer cells activity. So there is a number of things that are actually working against the pregnancy – especially homozygous mutations. In that case, Clexane would need to be used for the entire duration of the pregnancy. I would also check the dosage of Clexane – is it 0.2, 0.4 or 0.6 ? 0.2 is sub-therapeutic and it would be very weak for a homozygous mutation. In such case, 0.4 or even 0.6 could be possibly used. Natural Killer cells are a concern and they could possibly interfere with the pregnancy and cause a miscarriage. We usually offer Intralipid infusions to reduce the load of overactive immune activity. We do offer Prednisolone, which is a cortical steroid, to suppress the immune system a little bit. So there are a few possible avenues there. Of course we would need to see the Natural Killer cell loads first. And if there needs to be something additional (apart from Intralipid and Prednisolone) and more prolonged in terms of its usage, then we would probably need to involve the immunologist.
We do not offer spindle transfers. We do offer cytoplasmic transfers which are the opposite of the spindle transfers. We would essentially use the cytoplasm of the donor and inject it into the oocyte of the intended mother. So a spindle transfer – no, but a cytoplasmic transfer – yes.