Study Finds Answers to Unexplained Pregnancy Losses in the Placenta

Understanding the cause of miscarriage and stillbirth could help medical professionals identify risks and better inform pregnancy care.

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A recently published study sheds light on the approximately 50 percent of unexplained pregnancy losses in the United States. The researchers say the discovery could inform pregnancy care and help women understand the reasons behind their losses, aiding their healing process.

Of the approximately 5 million pregnancies in the United States annually 1 million end in miscarriage and more than 20,000 end in stillbirth. A miscarriage is defined as less than 20 weeks gestation and a stillbirth at or beyond 20 weeks. A full-term pregnancy is considered 40 weeks.

The study, published in the journal Reproductive Sciences, found answers to more than 90 percent of previously unexplained pregnancy losses by examining the placentas of mothers who lost their babies.

“To have a pregnancy loss is a tragedy. To be told there is no explanation adds tremendous pain for these loss families,” said Dr. Harvey Kliman, senior author of the study and a research scientist in the Department of Obstetrics, Gynecology, and Reproductive Sciences at Yale School of Medicine, in a statement on the Yale School of Medicine website.

The research team examined 1256 placentas from single-child pregnancies that ended in a loss. Of these, 70 percent were miscarriages, and 30 percent were stillbirths.

The team found that by adding two new categories to existing categories used to determine reasons pregnancies are lost, they could establish the pathologic diagnoses for 91.6 percent of the pregnancies—including 88.5 percent of the miscarriages and 98.7 percent of the stillbirths.

The new categories were “placenta with abnormal development”—or dysmorphic placenta—and “small placenta”—defined as a “fixed trimmed disk weight below the 10th percentile for cases ≥ 20 weeks.”

The researchers found that 86.2 percent of unexplained miscarriages were due to a dysmorphic placenta—associated with genetic abnormalities—and that 33.9 percent of unexplained stillbirths were due to a small placenta.

“This work suggests that the over 7,000 small placentas per year associated with stillbirths could have been detected in utero—flagging those pregnancies as high risk prior to the loss,” said Dr. Kliman in a statement on the Yale School of Medicine website. “Likewise, the identification of dysmorphic placentas may be one way to potentially identify genetic abnormalities in the almost 1 million miscarriages that occur in our country every year.”

The results that Dr. Kliman and his team have collected may prove very important in the future as birth rates worldwide are declining, and understanding why many pregnancies are lost could help medical professionals identify signs that may increase a woman’s risk of losing a pregnancy.

Tips for a Healthy Pregnancy

Pregnancy is a time of immense change in a woman’s body and her life. Although it can be a bit overwhelming, there are many things a woman can do to support a healthy pregnancy. Let’s look at some of the ways to support you and your baby to thrive in pregnancy and beyond.

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Take Folic Acid or Include Folate-Rich Foods in Your Diet

Folic acid is the synthetic form of the B vitamin, folate. Sufficient amounts of folic acid are crucial, especially in the first three months of pregnancy when the baby is developing. Adequate folic acid prevents neural tube defects in a growing baby, and deficiencies can cause birth defects such as anencephaly (in the brain) and spina bifida (in the spine). The rate of neural tube defects in the United States is about 3,000 per year.

According to the National Institutes of Health, pregnant mothers’ recommended daily allowance is 600 mcg (micrograms) of folic acid or folate.

Folate, the natural version of folic acid, is present in many foods, including dark, leafy green vegetables, eggs, whole grains, fresh fruit and fruit juices, sunflower seeds, beans, peanuts, liver, and aquatic foods.

Take a Good Multivitamin

Eating your vitamins and minerals is always preferable to taking a supplement. Still, when expecting, you may want to consider a high-quality prenatal vitamin to ensure you and your baby get everything you need. Adding a healthy diet increases the nutritional needs you provide to yourself and your little one.

A study of 2,450 pregnant women found that 90 percent of women do not get adequate nutrients during pregnancy from food alone and need prenatal vitamins to fill the gap. The study also found, however, that 99 percent of affordable supplements available do not contain appropriate doses of key micronutrients needed during pregnancy. This highlights the need for pregnant women to eat well and find a high-quality supplement to meet all their nutritional needs.

Eat a Healthy Diet

Eating a healthy diet is a good goal for all of us, but it is especially important when you are pregnant.

Because eating a healthy diet means something different to everyone, a good rule of thumb is to eat as much fresh, natural food as possible, avoid pesticides, eat organic, and limit processed foods. Eating all the colors of the rainbow will also help ensure you get plenty of helpful antioxidants while giving you and your baby as many vitamins and nutrients as possible.

Ensuring everything you eat is well cooked and washed thoroughly is also essential to ensure you are not putting yourself at risk of bacteria and parasites.

Some foods you may want to avoid are large fish that can accumulate high levels of mercury, like swordfish, shark, king mackerel, bigeye tuna, orange roughy, and marlin. Also, raw fish, especially shellfish, risk having bacteria and parasites like norovirus, Salmonella, Listeria, and Vibrio, so proceed with caution.

Eliminate Toxins

While you are pregnant, you are literally growing a new human being and will want to eliminate all toxins possible to ensure you give your baby the best chance at being healthy. Avoiding smoking and drinking while pregnant is advisable, but there are other toxins to be aware of as well. Things like hair color, nail polish remover, cleaning products, any products with strong smells or perfumes, and even changing cat litter should be avoided if possible when pregnant.

Cat feces can contain a type of parasite called Toxoplasma gondii that causes an infection called toxoplasmosis. It could be transmitted to your baby if you become infected while pregnant. Toxoplasmosis is found in raw or undercooked meat, raw eggs, and raw or unpasteurized milk. Cats that eat raw meat or small animals can become infected, but this doesn’t mean you should give away your cat! The risk of getting toxoplasmosis is low, especially if you have an indoor cat—but if you can avoid changing cat litter while pregnant, it’s a good idea to reduce your risk. You can learn more about toxoplasmosis on the Humane Society’s website.

Drink Lots of Water

Drinking lots of water is particularly important during pregnancy as it is an essential component of amniotic fluid that surrounds and protects the baby and breast milk. Not getting enough water during pregnancy can also lead to complications, including neural tube defects and premature labor. The American Congress of Obstetricians and Gynecologists recommends that pregnant mamas drink 8–12 cups of water daily.

Exercise Regularly

One of the best things you can do for yourself and your growing bundle of joy is to take the time to exercise every day. A great way to keep moving and get some fresh air is to walk outside daily, breathe fresh air, get some sun (and delicious vitamin D), and keep your energy moving.

Research also suggests that exercise during pregnancy improves women’s delivery experience, with one study showing that pregnant women who exercised in water had shorter labor duration and higher instances of normal births without complications.

Get Ample Sleep

Getting lots of good, restful sleep is vital when your baby is growing, as it takes a lot of energy—which you'll want to replenish daily. Additionally, once your sweet baby arrives, there will be considerably less sleep for you and everyone else in your house, so get in all you can now—you’ll be glad you did.

Eliminate Stress

Stress is never a good thing, but it is especially hazardous during pregnancy. We are learning that stress can make us more susceptible to various physical and mental health problems—from heart disease to anxiety and depression.

Eliminating as much stress as possible is essential for a healthy mama and her growing baby. Although this is easier said than done, be mindful to eliminate all the stresses you can to reduce the load, which allows you a little more energy for the unavoidable ones.

Daily meditation or prayer, yoga, going for walks, writing in a journal, and connecting with friends to talk about whatever is happening will help keep you grounded and your stress levels to a minimum.

Pregnancy is a beautiful time to focus on yourself and your baby and prioritize your health and well-being. Taking time daily to ensure you and your baby’s needs are met will help ensure good health for both of you in pregnancy and beyond.