Diet and Weight Gain

If you started pregnancy at a normal weight, you only burn about 90 extra Calories per day in the first trimester, 275 extra Calories per day in the second trimester, and 500 extra Calories per day in the third trimester.

Normal weight women (BMI of 18.5-24.9) should gain about 25-35 pounds during their pregnancies. Underweight women (BMI < 18.5) may need to gain more and overweight women less. For obese women (BMI > 30), dieting is safe and beneficial during pregnancy. Most weight gain comes in the second half of pregnancy and often women have gained no weight or even lost weight by their 20th week; this is healthy and okay.

If you’re pregnant with twin (or more!), the expected weight gain will be a little more than. Expected or average weight gain and necessary weight gain aren’t necessarily the same thing. We check your weight at every visit, but please don’t focus on how much you gain. We are usually not worried about you gaining too little weight but instead gaining too much weight. Excess weight gain increases the risks of several pregnancy complications, including the risks of preeclampsia, diabetes, fetal macrosomia (a big baby), and Cesarean delivery.

Many overweight women can gain no weight for the entire pregnancy or even lose some weight if they’re actively dieting. This is not a bad thing. Maternal weight gain, if it is excessive, is associated with a larger fetal size; but that doesn’t mean that gaining too little weight during pregnancy will not make your baby too small if you are overweight at the start of the pregnancy. The goal is to have a healthy baby and a healthy mom. Talk with your doctor or midwife about what your weight journey should look like throughout pregnancy based on your pre-pregnancy weight.

Because of high-levels of mercury, pregnant women should avoid shark, swordfish, king mackerel and tilefish. Smaller fish are usually safe, such as light tuna, salmon, pollock, and catfish. Up to 12 ounces per week of these fish is considered safe.

Foods to Avoid

This is a great question. The truth is, you can eat just about anything you want. Here is the quick and overly cautious answer:

Don’t eat:

  • Big fish with high levels of mercury (shark, swordfish, king mackerel, and tilefish)
  • Unpasteurized milk and soft cheeses
  • Raw or undercooked meats
  • Cold cuts (lunch meat, salami, etc.)

Here are the explanations:

Because of high levels of mercury in some big fish, pregnant women should avoid shark, swordfish, king mackerel, and tilefish. Smaller fish are usually safe, such as light tuna, salmon, pollock, and catfish. Up to 12 ounces per week of these fish is considered safe. In fact, regular consumption of fish (and their omega fats) has been associated with lower rates of preterm labor and other complications of pregnancy. Recent evidence suggests that even the recommendation about avoiding the larger fish is likely unnecessary. So don’t stress too much unless you happen to eat these larger fish multiples times per week.

Listeriosis is a rare type of food poisoning that can affect pregnant women and cause stillbirths. To avoid this, you should wash all fruits and vegetables before eating them and avoid eating unpasteurized milk or soft cheeses, raw or undercooked meats, poultry, or shellfish. Ideally, hot dogs and deli meats should be heated thoroughly prior to eating though the absolute risk of acquiring listeria from deli meats is extraordinarily low. Don’t be too freaked out about listeria; most women take a greater chance just by driving to the doctor’s office than by eating high-risk foods. The absolute risk of anything happening from eating any of these foods is incredibly low. So you shouldn’t worry too much, but pregnancy isn’t the time to explore strange and new foods from uncertain sources.


As with most things in life, moderation is the key. Scientific studies have not demonstrated any problems with caffeine consumption during pregnancy until a woman consumes over 700 mg per day. That’s a lot of caffeine! To be safe, and to make sure that a woman never approaches that amount of caffeine consumption, we recommend that women limit themselves to 350 mg of caffeine per day.

In general, you are okay to keep your morning ritual if it consists of an average cup of regular coffee or the average serving of a caffeinated soft drink. But beware, it is possible to overdo it with a large special order from Starbucks. If you drink a lot of caffeine prior to pregnancy, cutting it out altogether can produce daily headaches. All things in moderation, including caffeine.

Most soft drinks have about 40 mg per 12 ounces (Diet Coke has 46 mg). Most coffee has around 75 mg per eight ounces, but this amount varies widely. Most teas have around 40 mg per eight ounces. And energy drinks like Red Bull have about 80 mg per can. Check out this website for the amount of caffeine in your favorite beverage.