Drinking soda during pregnancy isn’t automatically dangerous, but regular consumption carries real risks. The sugar, caffeine, and acidity in most sodas can contribute to excessive weight gain, gestational diabetes, and worsening heartburn, all of which are already common pregnancy concerns. An occasional soda is unlikely to cause harm, but making it a daily habit is where problems start.
Sugar and Gestational Diabetes Risk
A single 12-ounce can of regular soda contains about 39 grams of sugar, which is close to the entire daily limit for added sugars recommended by most health guidelines. That sugar hits your bloodstream fast because there’s no fiber, fat, or protein to slow it down. During pregnancy, your body is already working harder to regulate blood sugar due to hormonal changes, and a steady intake of liquid sugar makes that job significantly harder.
Research has linked sugary cola specifically to a higher risk of gestational diabetes. Women who drank more than five servings of sugar-sweetened cola per week had a 22% greater risk of developing gestational diabetes compared to women who drank less than one serving per month. Gestational diabetes increases the chances of a larger baby, delivery complications, and a higher risk of type 2 diabetes for both mother and child later in life.
Beyond diabetes risk, the extra calories from soda can push weight gain past recommended levels. Liquid calories don’t trigger the same fullness signals as solid food, so it’s easy to consume 150 to 200 extra calories per can without eating any less at meals. Gaining significantly more than recommended during pregnancy is associated with larger babies and more difficult deliveries.
Caffeine in Common Sodas
The American College of Obstetricians and Gynecologists recommends keeping caffeine under 200 milligrams per day during pregnancy. Caffeine crosses the placenta, and intake above that threshold has been linked to roughly double the risk of miscarriage. Below 200 milligrams, studies have not found a significant increase in miscarriage or preterm birth risk.
Most sodas contain far less caffeine than coffee, but it adds up if you’re drinking multiple cans or combining soda with other sources. Here’s what a standard 12-ounce can contains:
- Coke, Coke Zero, or Pepsi: 34 to 38 mg
- Dr Pepper: 41 mg
- Diet Coke: 46 mg
- Mountain Dew: 54 mg
- Zero Sugar Mountain Dew: 68 mg
Some sodas are naturally caffeine-free. Most ginger ales (Canada Dry, Schweppes), lemon-lime sodas (Sprite, 7UP), and most root beers contain zero caffeine. Barq’s root beer is the notable exception at 22 mg per can. If caffeine is your main concern, these are safer picks, though the sugar content still applies.
One can of Coke at 35 mg is well within the limit on its own. But if you’re also having a cup of tea (about 50 mg) and a small coffee (95 mg), you’re already approaching the ceiling. Tracking total caffeine across all sources matters more than focusing on any single drink.
Diet Soda Isn’t Necessarily Better
Switching to diet soda eliminates the sugar problem but introduces different concerns. The FDA considers approved artificial sweeteners safe for the general population, including pregnant women. The one clear exception is for people with phenylketonuria (PKU), a rare genetic condition that makes it dangerous to consume aspartame, which is found in many diet sodas.
However, a study from the National Institutes of Health found that daily diet soda consumption during pregnancy was associated with heavier babies and higher rates of childhood obesity. Among pregnancies complicated by gestational diabetes, children born to mothers who drank at least one artificially sweetened beverage per day were 60% more likely to have a high birth weight. By age seven, those children were nearly twice as likely to be overweight or obese. Notably, daily diet soda offered no advantage over daily regular soda: children in both groups had similar obesity rates at age seven.
The most striking finding was what happened when women substituted water for sweetened beverages of either type. That simple swap reduced their children’s obesity risk at age seven by 17%. Water, not diet soda, was the clear winner.
Carbonation and Pregnancy Heartburn
Even if a soda is caffeine-free and sugar-free, the carbonation itself can be a problem. Heartburn affects the majority of pregnant women, especially in the second and third trimesters, as the growing uterus pushes the stomach upward and pregnancy hormones relax the valve between the stomach and esophagus.
Carbonated beverages are a known trigger for reflux symptoms. The gas expands in your stomach, increasing pressure and making it easier for acid to push back up. Citrus-flavored sodas and colas, which are also acidic on their own, can irritate an already inflamed esophagus even further. If you’re already dealing with heartburn, carbonated drinks of any kind tend to make it worse.
What to Drink Instead
Water is the simplest and most beneficial choice during pregnancy. If plain water feels boring, adding sliced fruit, cucumber, or mint can make it more appealing without adding significant sugar. Sparkling water with no added sweeteners is a step up from soda, though the carbonation can still aggravate heartburn for some people.
If you’re craving soda specifically, having one occasionally is a reasonable middle ground. The risks outlined above are tied to regular, daily consumption rather than the occasional can at a barbecue. Choosing a caffeine-free option and keeping it to a few times per week limits your exposure to the sugar, caffeine, and carbonation that cause the most concern. The key shift backed by research is making water your default drink rather than any sweetened beverage, regular or diet.