Demystifying the Real Reasons for Miscarriage

Last year four of my friends, and a few of my patients, healthy women in their 20s and 30s, had isolated miscarriages.

So far two have gone on to have healthy pregnancies and delivered healthy babies. In the case of my patients, we keep helping women post-miscarriage go on to have a healthy pregnancy.

No one knows exactly what caused these particular miscarriages in each case, but the one thing they each have in common is some degree of secrecy and shame.

It’s amazing to me that in the year 2017 miscarriage is still something people feel ashamed of or want to hide. Now, I am all for privacy and not telling the world just for the sake of an Instagram hug in the face of loss, but even my close friends have struggled to share the news with the people closest to them. They are sad, frustrated, confused and don’t know who to turn to to ask for help. They find their OBGYN’s dismissive and uninformative. Sometimes they are even scared to try again.

To me it’s essential for women to know that miscarriage is common and natural in many cases, that many women have miscarriages without knowing it. If you miscarry before your first missed period, you get a regular period which might be the same length or even shorter/lighter than your usual period, not necessarily heavier or abnormal!

An estimated 50% of pregnancies result in miscarriage early, before the woman knows she is pregnant and before the first missed period (so in weeks 1-4).

From there somewhere between 8% and 20% of known pregnancies miscarry before 20 weeks, with rates being lowest in women 20-30 (11%), higher in women over 35 (20%) and even higher in women over 40 (40% or higher). Women who have had a child previously are less likely to miscarry, and the risk of miscarriage goes down as gestational weeks go up. After 20 weeks the likelihood of miscarriage becomes very low, but still possible.

The top reasons for miscarriage are as follows:

• Chromosomal (aka DNA) abnormality. In this case the body identifies that there is a genetic problem with the embryo and terminates the pregnancy. This is the most frequent reason for miscarriage.
• Infection. A viral or bacterial infection or fever can trigger miscarriage.
• Thyroid disorder. 1 in 8 women will be diagnosed with a thyroid condition in her lifetime and at Parsley Health we identify autoimmune and other types of thyroid dysfunction early. One of my patients who miscarried had a high TSH, thyroid stimulating hormone. We caught this even though her OBGYN missed it. We started her on thyroid hormone support and she was successful in getting pregnant and delivered a healthy baby boy.
• Blood clotting disorders. These can be acquired or inherited. Some women are born with or develop clotting disorders like Factor V Leiden, which can result in recurrent miscarriage.
• Weight problems. -Obesity (BMI > 25) and being underweight (BMI < 18) are both associated with miscarriage. Note that over two-thirds of American adults have a BMI > 25.
• Celiac disease. If Celiac disease is untreated, meaning if you are still eating wheat or gluten , it can be associated with higher rates of miscarriage.
• Alcohol tobacco and cocaine abuse. The studies are inconclusive here as reliable reporting by pregnant women of use of these substances when pregnant is hard to come by, but all three are associated with some degree of higher miscarriage risk.
• NSAID use, like ibuprofen. This is also associated with higher miscarriage rates. This is a concerning fact given again, most miscarriages happen before women know they are pregnant and can knowningly avoid these drugs.

Another rare cause of miscarriage is amniocentesis or CVS, chorionic villus sampling, two invasive techniques for determining chromosomal or other abnormalities in a fetus. The rates are low ranging from 1 in 400 to 1 in 1000 in experienced hands of a provider doing the procedure.

Going into my pregnancy I had assumed I would do one of them given my age, 35, and the associated higher likelihood of chromosomal abnormalities.

Luckily thanks to a new blood test called Panorama, which samples fetal DNA in maternal blood, the most common abnormalities were ruled out, meaning my chances of finding a problem with the baby were 1 in 10,000. It’s a personal decision but for me the risk of accidental miscarriage with Amnio or CVS was higher than the chances of finding anything on the test so I elected not to get it done. The head of Obstetrics at Greater Baltimore Medical Center told me that Panorama had reduced their rates of Amnio and CVS by as many as two thirds in healthy women.

It’s important to note that caffeine intake has not been shown to increase risk of miscarriage.

So what does this all mean?

The takeaway for you, and our patients at Parsley Health, is that miscarriage is common and not something to be ashamed of. I always explain that it is the body’s wisdom and to trust it. It does not mean that you won’t go on to have a healthy baby and if your body ends the pregnancy, it’s best to be grateful for this natural intelligence.