How many miscarriages do we consider Recurrent?
The modern definition of Recurrent Miscarriage or Recurrent Pregnancy Loss (RPL) is two or more miscarriages. In the past it was thought that three was ‘too many’, but we find the same number of problems if we test after 2, 3, or more miscarriages.
The good news is that even women with multiple miscarriages still have a chance of a healthy pregnancy.
The chances of success are higher if you already have at least one child, before or in between your miscarriages, compared to women who have multiple miscarriages but no child.
If we do a relatively thorough set of tests for miscarriage (see below) we find a cause in most couples with two or more pregnancy losses.
Causes of Recurrent Pregnancy Loss / Multiple Miscarriages
There are many possible causes of miscarriage, and some women have multiple causes – some might be more important than others, but all of the things we test you for can increase your chance of another miscarriage.
Major causes of miscarriage are:
1. Diminished ovarian reserve (low egg supply) – if there are less eggs left in your ovaries there will be more genetically abnormal eggs, and a greater chance of miscarriage. Age is also a factor for egg quality and older women are more likely to have diminished ovarian reserve, but this can occur in young women as well. Risk factors for diminished ovarian reserve include smoking, ovarian surgery, STDs such as Chlamydia or Pelvic Inflammatory Disease, fallopian tube problems, endometriosis, a mom with early menopause, but many women don’t have known risk factors.
2. Problems with the uterus – some women are born with a congenital uterine abnormality like septate uterus, a dividing wall inside the uterus that increases the chance of miscarriage but can be surgically corrected. Other problems with the uterus are acquired – polyps of the lining of the uterus, and fibroid tumors (leiomyoma). Up to 25-50% of women have fibroids, but not all cause fertility issues or miscarriages – the number, size and location of the fibroids all matter. Scar tissue, especially from previous D&C procedures, can also be a problem.
3. Autoimmune conditions – antiphospholipid antibodies and lupus anticoagulant are autoimmune conditions where a woman can make proteins that can attack normal tissue in the body, including the baby’s placental tissue when you’re pregnant. These increase the chances of miscarriage, and rarely cause blood clots in the mom. We have treatments to prevent miscarriage in women with these antibodies. Immune system-related thyroid problems are more common in women with miscarriages, and serious autoimmune diseases like lupus also increase the risk of miscarriage but are not common.
4. Blood clotting disorders – most, but not all of these are genetically bases – you may be born with genes that can increase your risk of both miscarriage and blood clots (like blood clots in the leg veins, deep venous thrombosis or DVT, which can spread to the lungs and be dangerous, especially in pregnancy). The most common blood clotting disorders don’t often cause blood clots in the mom, but may put you at 2-3 times increased risk of miscarriage compared to women without the clotting problem. More serious blood clotting disorders exist, with a much higher chance of miscarriage or blood clots, but these are rare.
5. Hormonal problems – Thyroid problems or too much prolactin hormone may increase the risk of miscarriage, and untreated thyroid problems can increase the chance of OB complications.
6. Genetic rearrangements in either parent’s genetic makeup – such as translocations, where part of one chromosome is swapped or joined with part of another, are rare. They occur in 3-5% of women or their partners in couples with multiple miscarriages.
7. Male factor – men with abnormal sperm quality such as very low numbers of normal-shaped sperm (morphology) have more genetically abnormal sperm.
8. Lifestyle factors – Smoking, heavy drinking and drug use increase the chances of miscarriage. Caffeine intake beyond 1 cup of regular brewed coffee a day may increase a woman’s chance of miscarriage.
9. Infections – certain infections may increase miscarriages – this is controversial.
Are treatments available to prevent another miscarriage?
If we find one or more reasons for miscarriage, then we have treatments available to reduce your chance of another miscarriage, depending on what we found. Diminished ovarian reserve, depending on how severe it is as well as the woman’s age, may respond well to fertility treatments with a woman’s own eggs, or may require egg donation. Treatment for autoimmune conditions or blood clotting disorders can lower your chance of another miscarriage by a large amount, but we can never get you down to a zero chance of miscarriage – for example if you have a blood clotting disorder, and we treat you with a ‘baby aspirin’ a day (81 mg low-dose aspirin) combined with blood thinner shots (such as Heparin or Low Molecular Weight Heparin), your next pregnancy could still be genetically abnormal and end up as a miscarriage – the shots can’t fix the genetic abnormality. Blood thinners are given as small shots under the skin of your stomach area, and women or their partners can be taught to give these at home. Problems in the uterus may need surgery. If one partner has a genetic rearrangement we can do In Vitro Fertilization (IVF) with Preimplantation Genetic Diagnosis (PGD) to select healthy embryos without the genetic rearrangement, and IVF with PGD testing of all 24 chromosomes – Comprehensive Chromosome Screening or CCS – may help some couples even without a known genetic rearrangement. Another option for a couple with a translocation is to use donor eggs or donor sperm instead of the partner’s eggs/sperm who is carrying the genetic abnormality.
Anything different next time I’m pregnant?
We can check your progesterone levels and thyroid function early in pregnancy, with progesterone supplements or thyroid medication given if needed. Your pregnancy should be watched more closely with ultrasounds to check for normal growth and to find baby’s heartbeat in the first weeks of pregnancy. If unfortunately you do have another miscarriage, we can offer genetic testing to see if the pregnancy was genetically abnormal or not – if the baby had an extra chromosome (a trisomy; trisomy 21 is Down’s syndrome), we can tell if the genetic problem came from the egg or the sperm.
Who should I see for miscarriage testing?
You should see a fertility specialist (Reproductive Endocrinology / Infertility or REI MD) to look for causes of miscarriage after two or more miscarriages. If you do miscarriage testing, it’s best not to try to get pregnant until we know the results. Miscarriage tests may be expensive, but we will work with you to determine your insurance coverage. Some say there’s no ‘fertility issue’ if you’re getting pregnant easily each time but a baby is the outcome you want, not another miscarriage. Diminished ovarian reserve (low egg supply) is just as common in women with multiple miscarriages as it is in women who are having trouble getting pregnant (infertility), and we perform a specialized ultrasound to look at the number of small follicles in your ovaries (antral follicle count or AFC) and the size of your ovaries, and blood tests including FSH, Antimullerian Hormone (AMH) and possibly a Clomid Challenge Test (CCT).
If you have gone through the ordeal of multiple miscarriages and want help please get started here.