For many women having their first child, the risk of a stillbirth can be frightening. Even women who have had normal births and healthy children can fear the chance that their pregnancy can result in a stillbirth.

A stillbirth happens when a baby dies inside its mother's womb after 20 weeks, and while there are some common reasons why this could happen, there are also a lot of lesser-known causes of this tragic phenomena. The majority of stillbirths occur weeks before the mother goes into labor, but there is a small pool of women who experience stillbirths during the labor and birthing process. Stillbirths are very serious and tragic experiences, that can even result in the mother having PTSD afterwards. Stillbirths affect less than 1 percent of all pregnancies.

Just because a woman has a stillbirth during her first pregnancy, or just during one pregnancy, does not mean that she will not be able to get pregnant and have a healthy baby later.

Stillbirths have many causes, including placental problems, growth restrictions, and infections. However, there are also lesser known causes, like certain foods and herbs that can cause stillbirth, as well as factors like age and the amount of children a woman is carrying in her womb.

There are certain symptoms of a stillbirth that women can look for if they are worried or suspect that they might be at risk of a stillbirth. This includes monitoring how active their baby is, and noting if they notice a drop in the amount of movements, or notice no movements at all.

Here are fifteen different causes of a stillbirth that you might not have known.

15 Mom-To-Be's Age

Age is a huge factor for women when it comes to trying to get pregnant. There is no "perfect" age range necessarily for a woman to have a baby, though there are pros and cons to women having babies in different ages between their 20s and 30s. Factors that might contribute to a when a woman decides to have a baby is when she is in a relationship with someone she wants to have a baby with, what part of her life she is in, and if she feels financially secure enough to have a baby. When it comes to the chances of a stillbirth, women who are over the age of 35 run the greatest risk. One study found that women between the ages of 35 to 39 had a 1.9 times greater chance of having a stillbirth when compared to women who were 30 or younger. The study also found that women over 40 had a 2.4 greater chance when compared to the group of women under 30.

14 Catching The Flu

That's right, your seasonal flu can actually affect your baby, and researchers who studied a group of pregnant women in Australia found that women who were vaccinated against the flu had a 51 percent lower chance of having a stillbirth. When a woman has the flu, her immune system is suppressed, which can make a woman more susceptible to intracellular pathogens. The flu can also affect her baby and cause congenital abnormalities, such as those caused by fever. Studies done in the past have found a link between women who are infected with the flu and infant cancer rates as well. Aside from these effects on a growing baby, a woman's body is undergoing changes, such as her heart and lungs working extra hard with baby inside of her, that when she gets infected with the flu, it can put her at increased risk of pneumonia and other illnesses. The Flu has also been known to cause premature births and preterm labor.

13 Carrying Multiples

A woman who is pregnant with twins runs a higher risk of having a stillbirth than a woman who is only carrying one child. One study found that women who are pregnant with twins actually have an added risk of stillbirth 2 to 5 times greater than the chance of a woman pregnant with one child. Other research suggests that the chances for stillbirths in twins is actually even higher, with twins that share a placenta at a risk that is 13 times greater, and twins who have separate placentas 5 times higher, when compared to the chances of stillbirths in single pregnancies.

Another factor that is important when women are pregnant with twins, in order to lower the chance of a stillbirth, is timing the delivery of the babies properly. Research shows that the chances for a stillbirth to occur go up the longer multiples are in the womb. The American College of Obstetricians and Gynecologists (ACOG) recommends twins that share a placenta be delivered between 34 and 37 weeks, and twins with separate placentas be delivered at 38 weeks.

12 Falling Or Other Accidents

When a woman falls, her chances of a stillbirth go up. You might think you have it under control and don't typically classify yourself as a klutz, but falling during pregnancy is actually understandable. Why would pregnant women have a good chance of falling? As her pregnancy goes on, and the more her belly grows, the weight might pull her forward and make it harder for her to stay upright, increasing her chances of tripping or falling. Another reason why women might find themselves more prone to falling is that their body produces relaxin, which is a pregnancy hormone. This hormone helps relax her joints and connective tissue when she's trying to deliver her baby, but it can also cause her to be more unstable while she's trying to walk. If you fall or have another accident that might have caused trauma to your baby, talk to your doctor and monitor movements in the womb as well as any vaginal bleeding.

11 Catching A Dangerous Infection

About one in ten stillbirths are actually caused by infections, which include rubella, the flu, or cytomegalovirus. Some viruses can be passed to your baby through the placenta or during delivery as well, which can be very serious and dangerous to your baby's health. If a woman has an infection before getting pregnant, her pregnancy might actually make it worse and can lead to complications or worse, preterm labor. The important thing to remember when you are carrying a baby is prenatal care, and part of that is getting blood tests done to let you know if you are immune to any infections, like rubella or chickenpox. It can also let you know if you have been exposed to some other kind of infection like Hepatitis B or HIV, which you might be unaware you have.

10 Taking Prescription Painkillers

Prescription painkillers raise a woman's chance of having a stillbirth by 2.2, making her over twice as likely to have a stillbirth than a woman that does not take painkillers or any kind of drug, whether illegal or prescription. Prescription painkillers include Oxycodone, Hydrocodone, and Meperidine. Other medications that can cause problems during pregnancy include aspirin, which can cause blood complications, and medications that are used to treat depression and anxiety can cause heart problems for the fetus. Medications for depression and anxiety include Zoloft, Celexa, and Paxil.

Research done by Boston University showed that women who take prescription painkillers run the highest risk of causing birth defects in their babies during the first trimester, such as having a neural tube birth defect. In the second and third trimesters, when the baby is going through much of its brain development, women who take OTC pain medication like Tylenol, have a higher chance of having a baby with ADHD, according to a Danish study.

9 Eating Certain Foods

Certain foods can cause problems for your baby, including high-mercury fish, raw fish, raw eggs, organ meat, and caffeine. You might think that you're not one to enjoy these kinds of foods, but sometimes we don't realize the ingredients we're eating and it's very important to be aware. For example, you might not think that you eat raw eggs, but foods that actually might contain raw eggs as an ingredient include salad dressings, Hollandaise sauce, homemade ice cream, and cake icing. If you like a can or packet of tuna with some crackers for a snack, you might want to be careful of how many times in a month you actually reach for that snack. Steer clear of sushi, too much coffee, unwashed produce, and unpasteurized green juice, as these items can increase your risk of getting a bacterial infection, which can effect the health of your baby.

8 Consuming Certain Natural Herbs

Certain herbs are dangerous to consume in any form during pregnancy and cause several serious complications, like stillbirth, miscarriage, and premature births. Some of these herbs include saw palmetto, goldenseal, dong quai, ephedra, Pay D’ Arco, passionflower, black cohosh, and Roman chamomile. Arbor vitae can cause miscarriages and premature labor, as well as vomiting and asthma. Beth root can cause the womb to be stimulated before it needs to be, and can lead to a miscarriage or preterm labor. Black cohosh might also stimulate the womb causing a woman to go into labor much before she needs to be.

Many women prefer herbal remedies to ailments and would like to use these plant-based remedies when they get sick instead of having to take OTC or prescription medications. While some herbs are totally okay to be taken during pregnancy (in moderation), like echnicea, eucalyptus, ginger, lavender, and peppermint, some need to be absolutely avoided during pregnancy. The best way to know what is okay and what is not is to talk to your doctor before using any herbal supplement.

7 Having A Possible Cord Accident

Cord accidents are when something blocks the flow of blood to the baby through the umbilical cord. 10 percent of stillbirths can be attributed to cord accidents, which can be worrisome to those who fear they might be at risk of a stillbirth. Cord accidents can mean that there is a knot in the cord, or that something is obstructing the cord from delivering blood and nutrients to your baby. It can also mean that there is an abnormal complication with the cord in the body, or that there is a blood vessel in the cord that has ruptured.

Another accident includes a prolapsed cord, which is when the cord comes through the cervix before the baby does during the labor and birthing process. Other reasons that a cord accident might happen includes too little amniotic fluid being present, a blood pressure in the cord that is abnormal, and velamentous cord insertion, which is when the cord is not inserted properly into the placenta. However, cord accidents are rare during pregnancy.

6 Dealing With High Amounts Of Stress

High amounts of stress can wreck havoc on anyone's body, male or female, and pregnant or not pregnant. Stress can make you break out, gain weight, unable to sleep, have sore muscles, break out into a rash, and feel fatigued all the time. However, it is crucial for women to keep stress levels down when they are pregnant, especially because stress can trigger a woman to have a premature birth. One study that included over 2,000 U.S. women found that those who reported going through five or more stressful situations in the past year had a 2.5 higher chance of having a stillbirth when compared to the women who did not have any stressful events.

An interesting finding from the study was that women with the highest risk were those who either got into a fight with someone or had a partner go to jail in the past year. Ways to reduce stress can include setting aside time from a busy schedule to enjoy activities like taking a bath, reading a book, or listening to calming music.

5 Where Mom-To-Be Lives And Works

Air pollution can actually lead to birth defects and stillbirths. One study found that air pollutants like car exhaust and industrial waste can cause a spike in how much of a risk a woman has of having a stillbirth, when compared to a woman who is not exposed to these kinds of pollutants. Another study supported this claim, finding that women who are in their third trimester have a higher risk of stillbirth when exposed to fine particulate air pollution. Chemicals can also cause an increase risk of stillbirths and miscarriages, including chemicals that are released during fracking. Fracking is a method used to extract oil and gas, and has been linked to several heath problems in men and women. Fracking causes reproductive, immunological, and neurological toxic substances, carcinogens, and endocrine disrupting chemicals (EDCs) which have been linked to birth defects and stillbirths.

4 Being Unmarried

One study found that women who are unmarried actually run a higher risk of having a stillbirth when compared to women who are married. One study found that aside from running the risk of having a stillbirth, women who are not married and are having a child also run a higher risk of fetal and infant death, including being at a higher risk of having a baby with SIDS. This might actually be more of an effect of larger socioeconomic issues instead of something about an unwed woman's body. Another reason why unmarried women might have a higher risk of a stillbirth is potential stressful dynamics present in the couple's relationship or the situation that can lead to a higher risk of stillbirth.

3 Mom-To-Be's Drinking Water

A pregnant woman must be very careful of the water she drinks while is carrying a child as she runs a higher risk of stillbirth when she drinks water infected with certain chemicals or pollutants. For example, lead in drinking water has been linked to a higher rate of infant death and stillbirths. Another poison that can be found in drinking water is tetrachloroethylene or PCE, which has been linked to increased risk of stillbirths and other issues for a woman during pregnancy. A study published in the journal of Environmental Health studied over 1,000 pregnancies in the Cape Cod region where PCE was present in the water supply. The study found that women who were exposed to the poison in high amounts were over twice as likely to have a stillbirth and 1.4 times more likely to have placental abruption.

2 Existing Chronic Conditions

Chronic conditions can make pregnancy harder, because a woman's body is already altered due to the illness, and now she is undergoing more changes to care for her baby. Chronic conditions that can result in stillbirths include uncontrolled diabetes, high blood pressure, and kidney disease. These chronic conditions can also cause poor fetal growth and placental abruption, which is when the placenta detaches from the uterus either partially or completely before the baby is ready to be birthed.

HIV has also been associated with an increased risk of stillbirth. While HIV is not a direct cause of stillbirths, having HIV makes it easier for mom-to-be to contract a severe infection, thus leading to a possible stillbirth. Similarly, women who suffer from chronic CMV are at higher risk of having a compromised immune system, and consequently, have a higher chance of infection that may result in a stillbirth.

1 Not Breaking Bad Habits

Tobacco use during a pregnancy can cause a stillbirth, and one study by the National Institutes of Health found that women who use tobacco, marijuana, and other drugs are two to three times more likely to have a stillbirth when compared to women who do none of the above. The study even found that women who are exposed to secondhand smoke are at more of a risk of having a stillbirth when compared to women who are not exposed to secondhand smoke. The study tested women's blood for nicotine and also tested umbilical cords for traces of drugs. The findings yielded the increased risks for women based on the different kinds of drugs found, with tobacco and marijuana being the greatest risks to a normal, healthy pregnancy.

Secondhand smoke yielded a 2.1 times higher risk. Women who smoke who are looking to lower their chances of having a stillbirth should quit smoking before trying to get pregnant, and steer clear of nicotine and other drugs while pregnant. They should also be careful to stay away from places where secondhand smoke, and a lack of ventilation, is present.

Sources: American Pregnancy Association, Contemporary OB/GYN, The New York Times, The University of Auckland, Fit Pregnancy, National Center for Biotechnology Information, U.S. National Library of Medicine, Reuters, The American College of Obstetricians and Gynecologists (ACOG), VeryWell, NHS, March of Dimes, What To Expect, Baby Center, Consumer Reports, Authority Nutrition, The Guardian, The JAMA Network, The Washington Post