Mass General Brigham researcher Lidia Mínguez-Alarcón, PhD, MPH, Bpharm, and colleagues study how environmental factors such as diet or chemical exposure affect fertility. Their Environment and Reproductive Health (EARTH) Study, established in 2004 at the Massachusetts General Hospital Fertility Center, made an unexpected discovery about stress and fertility treatment outcomes.
“The original goal of the study wasn’t to look at stress. But using data from the study, we proved for the first time that the mother’s stress even before conception can affect pregnancy and birth outcomes,” says Dr. Mínguez-Alarcón. “And the mother’s stress before conception can have long-term consequences for her and her offspring.”
Other researchers have studied the effects of stress during pregnancy. As a result, we know that post-traumatic stress disorder (PTSD) and high stress during pregnancy can increase the odds of having early labor and a low-birth-weight baby (weighing less than 5 pounds, 8 ounces).
However, Dr. Mínguez-Alarcón says that before the EARTH Study, there was no existing research on the effects of stress before pregnancy begins.
The EARTH study enrolled over 1,000 women and included data on stress for 398 of the women. The people participating in the EARTH study used two different types of fertility treatment:
Intrauterine insemination (IUI): IUI is a procedure where a fertility specialist places sperm into the uterus to increase the chance of egg fertilization. IUI is also sometimes called artificial insemination.
In vitro fertilization (IVF): In IVF, a patient takes medication to stimulate egg production in the ovaries. A fertility specialist collects the eggs and fertilizes them with sperm in a lab. The fertility specialist then places one or more fertilized eggs (embryos) in the uterus.
People reported their stress levels by filling out a short questionnaire called the Perceived Stress Scale 4 (PSS-4). Researchers commonly use this questionnaire to collect data on stress. In the EARTH study, participants filled out the PSS-4 before pregnancy.
People in the study also provided medical history, smoking history, diet and nutrition information, and chemical exposure information.
Many people facing fertility challenges say that struggling to become pregnant takes an emotional toll. By the time they begin fertility treatments, they’re often already stressed.
“Fertility treatment itself is stressful,” says Dr. Mínguez-Alarcón. “Sometimes people go through many rounds of unsuccessful treatment before conceiving, so the level of stress just increases.” This stress has a notable impact on pregnancy and health.
By analyzing self-reported stress from the study participants, Dr. Mínguez-Alarcón and her colleagues found that:
More stress before pregnancy decreased the probability of having a live birth.
Stress before pregnancy decreased the probabilities of having a live birth in people undergoing IVF more than in people having IUI.
Participants who experienced more stress before conception were more likely to have high blood glucose (blood sugar) levels during pregnancy.
“Glucose levels are a marker of heart health,” says Dr. Mínguez-Alarcón. “High blood sugar during pregnancy can negatively impact the future health of the pregnant person and the baby.”
According to Mínguez-Alarcón, women who have high blood sugar during pregnancy (pre-gestational diabetes) are more likely to have type 2 diabetes and heart disease later. Gestational diabetes also increases the chances of premature birth and having a baby who develops type 2 diabetes, according to the Centers for Disease Control (CDC).
“Controlling stress levels before pregnancy is good not only to increase the chances of having a live birth but also to protect the health of the pregnant person during pregnancy and later,” says Dr. Mínguez-Alarcón. “If stress is an issue, this problem should be treated well before pregnancy. Controlling blood glucose levels by controlling stress levels preconception is key.”
Not all sources of stress are avoidable, but Dr. Mínguez-Alarcón offers these tips for reducing stress before pregnancy:
Consider seeing a counselor or therapist.
Eat healthy: food can impact your mood and overall health.
Exercise regularly.
Get enough quality sleep.
Join a support group for people with infertility.
Stay connected with people in your life.
She notes that there’s a strong association between loneliness and depression. Depression and stress are also highly linked. “Being in touch with family and friends is so important for lowering depression and stress,” she says.
If you’re experiencing anxiety, depression, or stress before, during, or after pregnancy, ask your provider for help. Your mental health is just as important as your physical health.
Using the current study data, the EARTH Study researchers plan to investigate the effects of preconception stress on cholesterol levels. High total cholesterol is a risk factor for heart disease, which may impact the health of the mother and child. They also plan to examine how the stress level of the male partner impacts fertility treatment outcomes.
In the future, the EARTH researchers would like to increase the diversity of study participants. Their goal is to include socioeconomic factors (things like income, education level, and type of job) as part of their analyses.