Miscarriage is a lay term for pregnancy loss. In medical terms, early miscarriage is usually referred to using the following terms:
- Chemical pregnancy loss (when HCG levels in the urine or blood rise initially to indicate pregnancy and then drop again, indicating that the pregnancy has ended)
- Early pregnancy loss (when an embryo or fetus that is clinically detectable through tests such as ultrasound is lost in the first trimester)
Video Transcript →
Perhaps the most important female fertility factor is the egg factor, by the time a woman starts menstruating about age thirteen she has half a million egg follicles left in her ovaries. Now an egg follicle is a sac that holds one egg. Every month she is going to release a batch of these egg follicles […] only one of those egg follicles will ultimately grow each month and ovulate and the rest will die. But every month women lose eggs. And with time they run out of eggs and that’s called Menopause.By the time a woman is thirty she loses ninety percent of her eggs by the time she is forty she loses ninety-seven percent. One thing we test for is called Ovarian reserve, that is how many eggs are left and unfortunately patients and some doctors don’t really know what this means. Ovarian reserve is used by fertility doctors to determine if a woman has low ovarian reserve because those patients make less eggs, therefore they have a lower chance of pregnancy with fertility treatment…the ovarian reserve can be tested in a variety of ways. The best way is to perform an ultrasound when that woman is on her period and count the resting egg follicles in the ovaries.
Other tests for ovarian reserve include blood test for the hormone Anti-Mullerian hormone or AMH and follicle stimulating hormone that’s FSH and estradiol. Overall the key message for ovarian reserve is it’s needed by fertility doctors to counsel women on the chance of success for fertility treatment.
What’s really important is called egg quality that’s different than ovarian reserve. Egg quality basically means the following: the ability of an egg to create a chromosomally normal embryo. Poor eggs create embryos with abnormal chromosomal make up and good eggs create embryos with normal chromosomal makeup. Egg quality impacts the chance of a healthy baby and it is very much age dependent. Women who are in their forties especially have the lowest egg quality and actually by the age of forty-five its very rare to find any quality eggs and pregnancy rates essentially go to zero.
First recommendation I have to couples trying to conceive is to have sex at the right time of the month, the egg only lives one day so having intercourse for the one or two days before ovulation and the day of ovulation is critical for conception. To help women determine when they are ovulating we use ovulation detection kits. When we see women who don’t have regular menstrual cycles it means they are not ovulating […] and reasons for not ovulating could be things such as thyroid problems, excess production of a hormone called prolactin, a medical condition called polycystic ovarian syndrome or just stress weight changes, a lot travel.
We can obtain blood to test for some of these hormones and of course do an ultra sound to look at the ovaries for polycystic ovarian syndrome. So these are simple tests that should be done on women who are not having monthly periods. Sexually transmitted diseases such as Chlamydia and Gonorrhea but not HPV or herpes, can lead to fallopian tube damage and that can be a very significant form of infertility, that requires in-vitro fertilization or surgery to fix.
There are some other conditions that cause fallopian tube blockage, such as pelvic surgery and also endometriosis […] fallopian tube openness or patency can be determined by a test using dye in which we put dye through the uterus and fallopian tubes and take x-ray pictures. One of the most devastating conditions we see is recurrent pregnancy loss, that’s where women are able to conceive and carry the pregnancy until eight or ten weeks and then lose the pregnancy over and over again.bOne of the reasons for recurring pregnancy loss is uterine cavity abnormality such as fibroids, muscle tumors, polyps which are little growth, scar tissue or birth defects that that woman was born with in her uterus. Fortunately we can treat a lot of those uterine factors as it relates to recurrent pregnancy loss using surgical modalities.
One of the most frustrating diagnosis that we give to patients is something called unexplained infertility. This is a diagnosis that is assigned when the semen analysis is normal for the male partner, a woman is ovulating, her uterus and tubes are normal, she is at an age that should have quality eggs but yet they are unable to conceive. Oftentimes couples with unexplained infertility have to consider in-vitro fertilization which takes over each of nature’s steps and tries to fix them and augment the chance of success. Couples who fail to get pregnant sometimes think that they are allergic to each other, there is a mismatch. We don’t believe that actually exists and the reason for that is when we do in-vitro fertilization and put the sperm into the egg almost in all cases we get an embryos and in many cases we get pregnancies.
What Causes Miscarriage?
The following are the most common known factors in miscarriage:
According to the American Society for Reproductive Medicine, the usual cause of early miscarriage is aneuploidy. This is an abnormality in the number of chromosomes (such as missing or duplicated chromosomes). Up to 60% of all miscarriages are thought to be the result of random chromosomal abnormality. The reason for most of these errors is not known. Women over the age of 40 are more likely to lose an embryo due to chromosomal abnormalities. In fewer than 5% of cases, a genetic abnormality in the chromosomes of one of the parents is found to be the cause.
Congenital malformation or acquired abnormalities in the uterus are found to be the cause of recurring miscarriage in about 10-15% of patients. Uterine septum (a congenital condition in which the interior of the uterus is divided by a partition of tissue) is a well known factor in miscarriage. Polyps and fibroids that may form later in life can also contribute to miscarriage. When an embryo implants on an abnormal surface, it cannot obtain adequate nutrition or establish blood flow.
Hormonal, metabolic, and autoimmune disorders may also play a role in recurring miscarriage. These conditions include:
- Endocrine disorders such as diabetes and PCOS
- Thyroid or adrenal dysfunction
- Antiphospholipid antibody syndrome in which antibodies attack the placenta. This condition also increases the risk of blood clots. APAS is identified as the cause of recurring miscarriage in 3-15% of patients.
How Common Is Miscarriage?
A high percentage of fertile women who have unprotected sex will experience loss of a pregnancy at some point. According to the American Society for Reproductive Medicine, 25% of recognized pregnancies end in miscarriage. The total number of miscarriages (including cases where the woman is unaware of the pregnancy) is estimated at about 50%. Pregnancy losses occurring within the first 8 weeks are most common. Few women experience miscarriage after the 12th week.
What You Should Know about Recurrent Miscarriage
A single miscarriage is not usually a cause for concern from a medical standpoint. However, consecutive miscarriages are rare, occurring in less than 5% of women. If you experience two or more miscarriages of in a row, you may wish to seek assistance from a reproductive specialist.
In some situations, there is an identifiable, medically treatable factor contributing to the loss of pregnancies. Many pregnancies simply end because of random chromosomal abnormalities in the egg or the developing embryo.
Recurrent miscarriage or early pregnancy loss can be physically taxing and emotionally devastating. Not knowing why this problem is happening can be especially distressing. Patients may experience feelings of self blame, failure, or desperation. It is important for patients to seek emotional support during this time. Professional mental health support may also be beneficial for patients coping with recurrent loss.
Pregnancy after Miscarriage
Fortunately, most women trying to conceive do go on to carry a healthy pregnancy to term after a miscarriage. This includes 60-70% of women who have experienced recurring pregnancy loss with no identifiable cause. Following a healthy lifestyle including good nutrition, diet, weight control, prenatal supplementation, exercise, rest, and general self care is the best course of action for women who wish to increase their chances of a normal pregnancy in the future.
Can Recurring Miscarriage Be Prevented?
Because the underlying cause of most miscarriages is chromosomal abnormalities, the various therapies and techniques typically promoted for prevention are not proven and are unlikely to be useful. This includes over the counter, herbal, and alternative treatments.
Occasionally, a patient is diagnosed with a medical condition that may cause or contribute to recurrent miscarriage. Treatment or correction of the underlying disease, deficiency, or abnormality may reduce the chance of future miscarriage for some patients.
Here are a few examples:
Problem: Identifiable genetic abnormalities in one or both parents or advanced maternal age increasing the risk of chromosomal abnormalities in the embryo.
Treatment: During an In Vitro Fertilization cycle, preimplantation genetic diagnosis (PGD) may be used to identify a chromosomally normal embryo for implantation.
Problem: Uterine problems including polyps, fibroids, or a uterine septum (distortion of the interior of the uterus by abnormal tissue formation).
Treatment: Surgery may be suitable for some patients to restore a normal uterine surface to enable implantation and ongoing support of future embryos.
Problem: Diabetes or insulin resistance (such as found in patients with PCOS)
Treatment: Management of blood sugar through lifestyle changes and/or with appropriate medications to consistently maintain blood sugar at normal levels.
Problem: Antiphospholipid antibody syndrome which may cause excessive blood clotting and an antibody reaction to the placenta.
Treatment: Blood thinning therapy with aspirin and heparin may help prevent clotting. According to the American Society for Reproductive Medicine, medical treatments such as leukocyte (white blood cell) immunization and intravenous immunoglobulin (IVIG) therapy for preventing miscarriage have no proven benefit at this time.
If your doctor finds other medical conditions such as low levels of progesterone hormone or other hormonal irregularities, these may be treated as well. The efficacy of such treatment for preventing recurring miscarriage is not yet known.