Pregnancy, Coffee, and Low Birth Weight Risks

If you’re pregnant and wondering whether your daily coffee habit could affect your baby’s health, new research provides clear answers. A major Swedish study tracked tens of thousands of pregnancies and found that caffeine—especially from coffee—can lead to longer pregnancies and smaller babies.

The short answer? Consuming 200–300 mg of caffeine per day during pregnancy increases the chance of having a low birth weight baby by 27–62%. Even 100 mg daily can extend pregnancy by hours, with coffee-based caffeine adding even more time.

What the Swedish Study Found

Researchers at Sweden’s Karolinska University Hospital analyzed dietary and birth data from over 60,000 pregnancies over ten years. They focused on maternal caffeine intake and how it correlated with pregnancy duration and newborn weight.

Caffeine Intake and Pregnancy Duration

Women who consumed around 100 mg of caffeine per day had pregnancies that lasted, on average, 5 hours longer. But when that caffeine came mainly from coffee—as opposed to tea or other sources—the delay was even greater: about 8 hours longer on average.

Caffeine and Low Birth Weight Risk

For mothers taking in 200–300 mg of caffeine daily, the risk of giving birth to a low birth weight infant rose significantly—by 27% to 62%. Low birth weight is associated with higher chances of respiratory issues and other health complications early in life.

How Much Caffeine Is Too Much?

The American College of Obstetricians and Gynecologists currently recommends limiting pregnancy caffeine intake to 200 mg per day. To put that in perspective, a Tall (medium) Starbucks coffee contains about 240 mg of caffeine—already above the guideline. Caffeine also comes from tea, cola, energy drinks, and chocolate, not just coffee.

Why This Matters for Pregnant Coffee Drinkers

Many pregnant people assume a cup of coffee a day is harmless, but this study suggests otherwise—especially if that coffee delivers a full 200 mg or more of caffeine. The source of caffeine matters too; coffee appears to have a stronger impact on extending pregnancy than other sources.

Frequently Asked Questions

How much caffeine is in a Starbucks Tall (medium) coffee?

A Starbucks Tall (medium) coffee contains approximately 240 mg of caffeine, which exceeds the recommended 200 mg daily limit for pregnant women set by the American College of Obstetricians and Gynecologists.

What amount of caffeine increases the risk of low birth weight?

Consuming 200 to 300 mg of caffeine per day during pregnancy is linked to a 27–62% higher risk of delivering a low birth weight baby, according to the Swedish study.

Does the source of caffeine change the pregnancy risks?

Yes. The study found that caffeine from coffee led to an average pregnancy extension of 8 hours, while 100 mg of caffeine from all sources extended pregnancy by about 5 hours. Coffee may have a stronger effect than other sources like tea.

How much caffeine is considered safe during pregnancy?

The American College of Obstetricians and Gynecologists recommends a maximum of 200 mg of caffeine per day during pregnancy to reduce risks including low birth weight and prolonged gestation.

Can tea or cola caffeine affect pregnancy the same way as coffee?

All sources of caffeine contribute to total intake, but the study showed that caffeine from coffee had a greater effect on pregnancy duration. All forms—including tea, cola, energy drinks, and chocolate—should be considered when tracking daily caffeine.

Recommended FrontStreet Coffee for Non-Pregnant Coffee Lovers

For those not currently pregnant but still passionate about coffee, try FrontStreet Coffee’s Ethiopia Yirgacheffe for bright citrus and floral notes, or their PWN Golden Mandheling with its sweet caramel and almond profile. Both are single-origin specialty coffees roasted in small batches to highlight origin character. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.