Alicia was my last patient of the morning. Throughout her ultrasound, her eyes stayed glued to my face as I searched in vain for good news on the screen. Instead, I showed her what I saw — that her embryo did not have a heartbeat. “I don’t understand,” she kept repeating. “I’m healthy, I take care of myself. How could this happen?”
For many people, the sudden end of a pregnancy gives rise to a thousand thoughts and feelings. Suddenly, you’re not sure what this means about your body or your ability to have a healthy pregnancy, and you certainly aren’t sure what might happen next. Of the questions that patients ask me, the first is almost always, “Why did this happen to me?”
Causes of miscarriages
Why do miscarriages happen? Doctors who practice obstetrics sometimes find it amazing that a healthy pregnancy ever occurs, given how easy it is for something to go wrong.
There has not been extensive research on miscarriage, and new information comes out all the time. However, we do know that there are four general categories that explain why pregnancy loss usually happens.
- Chromosomal. Problems with the embryo’s DNA, like an extra copy of a chromosome, cause up to 60% of pregnancy losses. In these cases, the pregnancy wasn’t healthy from the start. One mismatch, or one wrong cell division, and the pregnancy is doomed. Even if the chromosome number is correct, there can be genetic problems within the chromosomes that don’t allow a pregnancy to progress.
- Problems with the uterus. Some people are born with a uterine septum. This wedge of tissue within the womb divides the inside of the uterus into two sections. If the placenta implants on a septum, it can’t adequately deliver oxygen and nutrition to a fetus. A weakened cervix that dilates months before the baby has developed enough to survive outside the womb also can cause miscarriage in the second trimester.
- Certain medical conditions. Serious and uncontrolled conditions — like severe diabetes, high blood pressure, blood-clotting disorders, thyroid disease and autoimmune disease — are associated with pregnancy loss. This is because hormone levels outside the standard range, impaired placental blood vessels and antibodies caused by these conditions directly harm the pregnancy.
- Infections. Listeria, toxoplasma, rubella, cytomegalovirus, mycoplasma, ureaplasma, chlamydia, herpes virus, parvovirus and a host of other infections have been associated with miscarriage.
What does not cause miscarriages
Now for a short, but by no means definitive, list of all the things that did not cause this pregnancy to be a miscarriage:
- Exercise, heavy lifting or physical exertion. Don’t worry about the fact that you vacuumed your house, moved a few heavy boxes, or lifted your niece or nephew. Even if you have a job that involves lifting mattresses or pushing heavy carts. Even if you bench-pressed 150 pounds on a few occasions or ran a marathon (which is amazing). No amount of typical physical activity can cause a miscarriage.
- Working. There’s no link between miscarriage and full-time employment, standing more than six hours a day, or an average amount of lifting. While some jobs may be associated with a higher risk, it’s unlikely your job had anything to do with your miscarriage.
- Screen time. Working at a computer all day or spending a lot of time on your social media accounts is not associated with miscarriage. The electromagnetic fields from computer screens are weak. While staring at a screen all day may not be good for your eyesight or your relationships, it doesn’t threaten your pregnancy.
- Air travel. Cabin pressurization isn’t associated with higher miscarriage risk. However, if you do fly while you’re pregnant, be sure to regularly get up and walk the aisle to prevent blood clots in your legs. Pregnancy does increase your risk of those.
- Frights. There are myths about a shock or fright causing a miscarriage. That’s not true, either. Enjoy all the horror movies you want.
- Sex. I don’t care how vigorous the sex was, how athletic or in what position. In fact, I hope all those things were superfun. No amount of sex (or an orgasm, with or without intercourse) can disrupt your pregnancy.
- Caffeine. Moderate caffeine consumption (2 cups of coffee or 3 to 5 cans of soda a day) is OK while pregnant.
- Tampons. Tampons stay in your vagina and go nowhere near the baby inside the uterus.
- Hormonal birth control. Hormonal contraception doesn’t fundamentally change your ovaries, your eggs or your uterus, and it has no impact on the health of your pregnancies. While the injection can delay your periods from returning for up to a year, you’ll still be able to have a healthy pregnancy once the hormonal effects wear off. If your hormonal birth control failed and you became pregnant while using it, there is no increased risk of miscarriage.
- An intrauterine device (IUD). Similarly, having used an IUD in the past doesn’t increase your risk of miscarriage. The only association with an IUD and miscarriage is in the rare instances when you become pregnant with an IUD in place. These pregnancies have a high risk of miscarriage, especially if the IUD is not removed.
- A past abortion. It isn’t uncommon for people to feel that their decisions about past pregnancies are the reason for a present-day miscarriage. Medically, a past abortion — even if you’ve had more than one — has no impact on your pregnancies in the future. You made the best decision for yourself that you could at the time, and an abortion does not damage your uterus so that you can’t get pregnant again. The universe is not sending you a message.
- Morning sickness. My patients have asked me if their babies were nutritionally deprived because they were nauseous all the time and couldn’t eat or were vomiting throughout the day. No matter how much you vomited or how little you ate, morning sickness does not lead to miscarriage. In fact, it’s associated with high pregnancy hormone levels that tend to indicate healthier pregnancies.
- A flu shot. The effects of flu vaccines on pregnancies have been heavily researched. Despite what you may have heard, getting the flu vaccine during pregnancy is not only safe, but also highly recommended. If you were to get the flu while pregnant, you would have a higher risk of serious illness — and even death — than getting the flu at any other time. Getting the flu vaccine won’t cause a miscarriage and will keep you and your baby safe, both before and after birth.
Bottom line: You did nothing wrong. You did nothing to make this happen.
It’s not your fault
Patients come to my miscarriage clinic at all stages of the process, from freshly receiving the diagnosis to seeing me weeks after it’s over. I make sure to cover the list of things that don’t cause pregnancy loss. I always say, “It’s OK to be sad, but it’s not OK to feel guilty.” Nine times out of 10, their shoulders slump with relief, and they rattle off the list of activities and behaviors that they’ve been secretly fearing had caused their miscarriage.
Almost all the patients I care for think that somehow the loss is their fault. They may feel like their actions led to the miscarriage — or worse, their partners or their parents or a friend implied or outright accused them of being irresponsible. The only thing worse than losing a pregnancy is thinking that it’s your fault. Society is often quick to blame pregnant people for a bad outcome, and all this does is make a bad situation worse.
We can’t control the outcome of a pregnancy any more than we can completely control when we get pregnant in the first place. Your pregnancy loss is not your fault.
This is an excerpt from Dr. Kate’s book, Your Guide to Miscarriage & Pregnancy Loss.
Relevant reading
The Mayo Clinic: Faith – Hope – Science
The Mayo Clinic: Faith – Hope – Science is the companion book to the two-hour PBS documentary of the same title. This book features interviews with patients including John McCain and the Dalai Lama and tells the story of William Worrall Mayo, an English immigrant who began practicing medicine with…
