Ask the Doctors: Small amount of caffeine is OK during pregnancy

Dear Doctors: Is it true a little coffee is OK when you’re pregnant? My weekly cup is a big treat, and I want a good answer when the barista at my coffee shop scolds me for not getting decaf.

Dear Reader: When it comes to coffee — and we’re talking about caffeine here — the current guidance recommends limiting intake to a maximum of 200 milligrams a day.

A 12-ounce cup of brewed coffee has 70 to 250 mg of caffeine, depending on the type of beans and the method used to make it.

Instant coffee comes in on the lower end of the range, while a well-known national chain of coffee shops reports 260 mg of caffeine in its 12-ounce size.

Caffeine’s also present in soft drinks, chocolate, tea, energy drinks and some medications.

And be sure to read the labels on energy bars or energy drinks. They can pack in from 50 to 300 mg of caffeine.

The 200 mg daily limit comes amid years of debate about the safety of consuming caffeine during pregnancy.

Research has yielded often-conflicting results. Some older studies observed certain adverse effects associated with daily caffeine consumption, but subsequent studies didn’t replicate those findings.

Several more recent studies suggest that regular caffeine consumption might lead to a small decrease in birth weight, which is a persuasive argument for observing the recommended limits.

It’s important to remember that caffeine crosses the placenta to the baby, which at this stage of life does not have the enzymes needed to break it down.

A recent study by University of Pennsylvania researchers found that consuming a modest amount of caffeine was associated with a surprising benefit to the mother. Up to 100 mg a day during the second trimester was associated with a reduced risk of developing gestational diabetes. That’s a type of diabetes that occurs during pregnancy in someone who was not previously diabetic.

All of this makes the caffeine question a knotty one.

The single cup of coffee a week that you’re allowing yourself during pregnancy is well below the recommended maximum.

If you’re unsure about your choice, bring it up with your obstetrician.

Dr. Eve Glazier and Dr. Elizabeth Ko are internists at UCLA Health.