Being an expecting mom can be one of the most stressful periods in a woman’s life. Thanks to alarmist pregnancy advice from friends and family as well as a multitude of books and official recommendations, it’s often difficult to figure out which pregnancy woes can cause problems. Here, Emily Oster, PhD, an assistant professor of economics at the University of Chicago and a proud parent, uses her expertise in statistics and economics to evaluate several medical studies on myths concerning moms-to-be.

Myth 1: Coffee is off limits for pregnant women.

A common pregnancy myth is that caffeine can increase a mom’s risk for miscarriage. Official and unofficial recommendations on coffee intake for pregnant women range from “moderate is OK” to “no caffeine at all.” But after Oster looked at medical studies, she found there is actually no documented evidence that consuming 2 to 4 cups of coffee each day would increase an expectant woman’s risk in any measurable way. So, drink up!

Myth 2: Prenatal testing should be different for women older than 35.
Since older women are at higher risk for having a disabled child, a common recommendation is that expecting mothers older than 35 should undergo more extensive prenatal testing to look for genetic abnormalities in their children. But these tests, such as a CVS test or amniocentesis, can also increase an older woman’s risk of miscarriage. This is why, Oster says, the decision about whether to undergo these potentially harmful tests should be based on a woman’s values after weighing the options, not on her age. And the American College of Obstetricians and Gynecologists agrees.

Myth 3: Having sex while pregnant jump-starts labor.
Women who have sex late in pregnancy don’t go into labor any faster than women who don’t engage in sexual activity. But apparently nipple stimulation, if done for a few hours each day, can trigger an infant’s arrival.

Myth 4: Having an epidural means longer labor.
True (but just slightly).
An epidural involves doctors injecting painkilling drugs into the small of the back through a fine tube. Some sources claim that it increases labor time for hours; others say it has no effect. According to Oster, the truth lies somewhere in the middle. An epidural does lengthen labor, but only by about 15 minutes. For many women, avoiding the pain is well worth the time.

Myth 5: Unpasteurized soft cheeses are unsafe for pregnant women.
The main reason expecting moms are warned not to eat unpasteurized soft cheeses is because of possible exposure to listeria, a dangerous bacteria that can lead to miscarriage or stillbirth. But pregnant women can safely eat cheeses made from pasteurized milk.

Still worried about your pregnancy? Chill out! Stressed-out moms-to-be may be putting their kids at an increased risk of obesity. Click here to read more.