First Trimester Nutrition

Ideally nutritional status should be assessed prior to conception, which allows any necessary dietary changes to occur and healthy habits to be established prior to pregnancy. The pre-conception check-up might also include discussion of immunization status, vitamin and mineral supplementation (prenatal vitamin), menstrual history, previous pregnancies, general health and weight, medical conditions and medications, caffeine, alcohol, tobacco, and other drug use. Your doctor will suggest ways to maximize your chances for a healthy pregnancy.

The major organs all begin forming during the first trimester, so a healthy environment right from the start is critical to the baby’s development. Here’s a quick overview of organ formation:

4 weeks: placenta and amniotic sac begin formation
5 weeks: neural tube is forming - this will eventually become spinal cord, nerves, and vertebrae. Heart and circulatory system begin to form.
6 weeks: heart is beating at 100-160 BPM, nose, mouth and ears begin to form, intestines develop, brain, muscles, and bone are all starting to form
7 weeks: liver has started making blood cells, the appendix and pancreas have formed, hands and feet develop
8 weeks: fingers and toes form
9 weeks: the heart divides into 4 chambers, eyes are fully formed, placenta takes over hormone production
10 weeks: kidneys are in place

Because development of vital organs begins almost immediately, it is crucial to take a prenatal vitamin containing 0.4 to 0.8 mg of folic acid and eat a balanced diet beginning in the pre-conception period.

Calories are the most important factor in determining birth weight. Most women do not need to increase their caloric consumption until the second trimester when an additional 340 calories per day are needed, while 450 extra calories are typically needed in the third trimester.
Protein: the recommendation is 1.1 g/kg/d, which is slightly higher than the non-pregnant woman (0.8 g/kg/d)
Carbohydrate: recommendation is 175 g/d (130 g/d for non-pregnant women)
Fat: intake of polyunsaturated fatty acids appears to have a positive effect on neurodevelopment, while trans-fatty acids may have adverse effects on fetal development.
Vitamin: make sure you’re taking a prenatal vitamin that contains folic acid. For a breakdown of micro-nutrients and their roles in pregnancy, please see the vitamin supplementation in pregnancy article
Mercury: found in certain fish. Pregnant women should avoid eating shark, swordfish, and other fish high in mercury. Shrimp, salmon, and tuna are low-mercury fish and also contain healthy fats; these can be eaten twice per week.
Caffeine: 200 mg or less per day is recommended. The amount of caffeine varies among brands of soda, coffee, tea, and chocolate. Coffee (8 oz) has approximately 100-250 mg. Soda (12 oz) has about 50 mg. Tea (8 oz) has about 35 mg. Chocolate can be quite variable, but may be up to 25 mg/serving.
Artificial sweeteners: there is no evidence that these increase the risk for birth defects
Food handling: it is generally advised to not eat raw or undercooked meat, fish, or eggs. The exception to this is sushi. Appropriate freezing of raw fish eliminates most parasites and bacteria, so sushi is considered safe.
Restrictions: it may be difficult for women who eat a vegan diet, have a health condition that causes malabsorption, or who have many food allergies to obtain adequate amino acids, iron, minerals, vitamins, and calcium for normal fetal development. A dietician should be consulted to maximize maternal and fetal health.

In general, women who eat three meals per day containing vegetables, fruit, whole grain, low fat dairy, and lean protein usually have adequate nutrition. In contrast, women who skip meals or have a high intake of candy, soda, cookies, and chips are more likely to be deficient in some area.

Although the calorie requirement does increase during pregnancy, the increase is not substantial. Likewise, pregnant women do need to gain weight, though iit may not need to be substantial.

BMI < 18.5 (underweight): gain 28-40 pounds
BMI 18.5-24.9 (normal weight): gain 25-35 pounds
BMI 25-29.9 (overweight): gain 15-25 pounds
BMI > 30 (obese): gain 11-20 pounds

BMI stands for body mass index, and you can calculate yours with the following formula:

weight in kg / (height in meters x height in meters)

In conclusion, proper nutrition should start prior to pregnancy and continue into the postnatal period. Small increases in calories, protein, and carbohydrates are indicated and should come from nutritious and variable food sources. A moderate amount of weight gain should also occur during pregnancy and be based on the woman’s pre-pregnancy weight.