16 Nutrition in the Lifecycle – Conception to Pregnancy


  • Essential nutrients required before conception
  • Optimal weight gain during pregnancy
  • Nutrients needs during pregnancy
  • Foods & beverages to avoid when pregnant
  • Fetal Alcohol Syndrome
  • Gestational Diabetes

This chapter will examine how a nutritious diet is essential for the mother and father before conception. We will learn the impact on the mother and child’s health based on the mother’s weight gain during pregnancy.

The Early Days of Pregnancy

Pregnancy is measured from the first day of a woman’s last menstrual period until childbirth and typically lasts about forty-two weeks. It begins with the first trimester (weeks one to week twelve), extends into the second trimester (weeks thirteen to week twenty-seven), and ends with the third trimester (week twenty-eight to birth). Changes begin to occur in the earliest days, often weeks before a woman even knows that she is pregnant. During this period, adequate nutrition supports cell division, tissue differentiation, and organ development. Therefore, women trying to conceive should make proper dietary choices to ensure a healthy baby’s delivery. Fathers-to-be should also consider their eating habits. A sedentary lifestyle and a diet low in fresh fruits and vegetables may affect male fertility. Men who drink too much alcohol may also damage the quantity and quality of their sperm.

Watch how fast growth occurs during the first trimester


Weight Gain during Pregnancy

During pregnancy, a mother’s body changes in many ways. One of the most notable and significant changes is weight gain. If a pregnant woman does not gain enough weight, her unborn baby will be at risk. Poor weight gain, especially in the third trimester, could result in low birth weight, infant mortality, and intellectual disabilities. Infant birth weight is one of the best indicators of a baby’s future health. Pregnant women of normal weight should gain between 25 and 35 pounds throughout the entire pregnancy. The precise amount that a mother should gain usually depends on her beginning body mass index (BMI). The Institute of Medicine (IOM) recommends that women with a BMI  between 18.5 and 24.9 gain 25-35 pounds.

IOM’s Recommended Weight Gain

Prepregnancy BMI Weight Category Recommended Weight Gain
Below 18.5 Underweight 28–40 lbs.
18.5–24.9 Normal 25–35 lbs.
25.0–29.9 Overweight 15–25 lbs.
Above 30.0 Obese (all classes) 11–20 lbs.

A starting weight below or above the normal range can lead to complications. Pregnant women with a prepregnancy BMI below twenty are at a higher risk of preterm delivery and an underweight infant. Pregnant women with a prepregnancy BMI above thirty have an increased risk of needing a cesarean section during delivery. Therefore, it is optimal to have a BMI in the normal range before pregnancy. Women pregnant with more than one fetus are advised to gain even more weight to ensure their unborn babies health.

The weight an expectant mother gains during pregnancy is almost all lean tissue, including the placenta and fetus. Women gain 2 to 5 pounds in the first trimester. After that, it is best not to gain more than one pound per week. Weight gain often breaks down in the following manner, as shown below.


Pregnancy Weight Distribution

Blood 3-4 pounds

Protein and fat storage 8-10 pounds

Body fluids 3-4 pounds

Breast 1-2 pounds

Baby 6-8 pounds

Placenta 1-2 pounds

Uterus 1-2 pounds

Amniotic fluid 2-3 pounds

The pace of weight gain is also important. If a woman puts on weight too slowly, her physician may recommend nutritional counseling. If she gains weight too quickly, especially in the third trimester, it may result from edema or swelling due to excess fluid accumulation. Rapid weight gain may also result from increased calorie consumption or a lack of exercise.

Weight Loss after Pregnancy

New mothers lose some weight during pregnancy with their child’s delivery during labor. They continue to shed weight in the following weeks as they lose accumulated fluids, and their blood volume returns to normal. New mothers who gain healthy weight and participate in regular physical activity during their pregnancies also have an easier time shedding weight post-pregnancy. However, women who gain more weight than needed for a pregnancy typically retain that excess weight as body fat. If those few pounds increase a new mother’s BMI by a unit or more, that could lead to complications such as hypertension or Type 2 diabetes in future pregnancies or later in life.

Nutritional Requirements

As a mother’s body changes, so do her nutritional needs. Pregnant women must consume more calories and nutrients in the second and third trimesters than adult women. However, the average recommended daily caloric intake can vary depending on the activity level and the mother’s average weight. Also, pregnant women should choose a high-quality, diverse diet, consume fresh foods, and prepare nutrient-rich meals. Steaming is the best way to cook vegetables. Vitamins are destroyed by overcooking, whereas uncooked vegetables and fruits have the highest vitamin content. It is also standard for pregnant women to take prenatal supplements to ensure adequate micronutrients intake.

Energy and Macronutrients

During the first trimester, a pregnant woman has the exact energy requirements as normal and should consume the same number of calories. However, as the pregnancy progresses, a woman must increase her caloric intake. According to the IOM, she should consume an additional 340 calories per day during the second trimester and 450 calories per day during the third trimester. This is partly due to increased metabolism, which rises during pregnancy and contributes to increased energy needs. A woman can quickly meet these increased needs by consuming more nutrient-dense foods.

During pregnancy, the recommended daily allowance, or RDA, of carbohydrates is about 175 to 265 grams per day to fuel fetal brain development. The best food sources for pregnant women include whole-grain bread and cereals, brown rice, root vegetables, legumes, and fruits. These and other unrefined carbohydrates provide nutrients, phytochemicals, antioxidants, and the extra 3 mg/day of fiber recommended during pregnancy. These foods also help build the placenta and supply energy for the growth of the unborn baby.

Protein builds muscle and other tissues, enzymes, antibodies, and hormones in the mother and the unborn baby. During pregnancy, extra protein is needed to synthesize new maternal and fetal tissues. Additional protein also supports increased blood volume and the production of amniotic fluid. The RDA of protein is 71 grams per day during pregnancy, which is 25 grams above the normal recommendation. Protein should be derived from healthy sources, such as lean red meat, white meat, poultry, legumes, nuts, seeds, eggs, and fish. Low-fat milk and other dairy products also provide protein, calcium, and other nutrients.

There are no specific recommendations for fats in pregnancy, apart from following normal dietary guidelines. Although this is the case, it is recommended to increase the amount of essential fatty acids because they are incorporated into the placenta and fetal tissues. Fats should make up 25 to 35 percent of daily calories, and those calories should come from healthy fats, such as avocados. It is not recommended for pregnant women to be on a very low-fat diet since it would be hard to meet the needs of essential fatty acids and fat-soluble vitamins. Fatty acids are important during pregnancy because they support the baby’s brain and eye development.


Fluid intake must also be monitored. According to the IOM, pregnant women should drink 2.3 liters (about 10 cups) of liquids per day to provide the body with enough fluid for blood production. It is also important to drink liquids during physical activity or hot and humid outside to replace fluids lost to perspiration.

Vitamins and Minerals

The daily requirements for nonpregnant women change with the onset of pregnancy. Taking a daily prenatal supplement or multivitamin helps to meet many nutritional needs. However, most of these requirements should be fulfilled with a healthy diet. The following table compares the standard required vitamins and minerals levels to those needed during pregnancy. For pregnant women, the RDA of nearly all vitamins and minerals increases.

 Recommended Nutrient Intakes during Pregnancy

Nutrient Nonpregnant Women Pregnant Women
Vitamin A (mcg) 700.0 770.0
Vitamin B6 (mg) 1.5 1.9
Vitamin B12 (mcg) 2.4 2.6
Vitamin C (mg) 75.0 85.0
Vitamin D (mcg) 5.0 5.0
Vitamin E (mg) 15.0 15.0
Calcium (mg) 1,000.0 1,000.0
Folate (mcg) 400.0 600
Iron (mg) 18.0 27.0
Magnesium (mg) 320.0 360.0
Niacin (B3) (mg) 14.0 18.0
Phosphorus 700.0 700.0
Riboflavin (B2) (mg) 1.1 1.4
Thiamine (B1) (mg) 1.1 1.4
Zinc (mg) 8.0 11.0

The micronutrients involved with building the skeleton—vitamin D, calcium, phosphorus, and magnesium—are crucial during pregnancy to support fetal bone development. There is an increased need for all B vitamins during pregnancy. Adequate vitamin B6 supports the metabolism of amino acids, while more vitamin B12 is needed to synthesize red blood cells and DNA. Additional zinc is crucial for cell development and protein synthesis. The need for vitamin A also increases, and extra iron intake is essential becauseAn illustration of an infant with Spina Bifida of increased blood supply during pregnancy and supports the fetus and placenta. Iron is the one micronutrient that is almost impossible to obtain in adequate amounts from food sources only. Therefore, even if a pregnant woman consumes a healthy diet, there still is a need to take an iron supplement in the form of ferrous salts. Also, remember that folate needs increase during pregnancy to 600 micrograms per day to prevent neural tube defects. This micronutrient is crucial for fetal development because it helps produce the extra blood a woman’s body requires during pregnancy.

Taking megadose supplements can lead to excessive amounts of certain micronutrients, such as vitamin A and zinc, which may produce toxic effects resulting in congenital disabilities. For most other minerals, recommended intakes are similar to those for nonpregnant women, although pregnant women must meet the RDAs to reduce the risk of congenital disabilities. Also, expectant mothers should avoid exceeding any recommendations.

Guide to Eating during Pregnancy

While pregnant women have an increased need for energy, vitamins, and minerals, nutrient-dense foods are essential to a healthy diet. Examples of nutrient-dense foods include fruits, whole grains, peas, beans, reduced-fat dairy, and lean meats. Pregnant women should meet almost all of their increased needs via a healthy diet. However, expectant mothers should take a prenatal supplement to ensure an adequate intake of iron and folate. Here are some additional dietary guidelines for pregnant women:

  • Eat iron-rich or iron-fortified foods, including meat or meat alternatives, bread, and cereals, help satisfy the increased need for iron, and prevent anemia.
    To enhance iron absorption, include vitamin C-rich foods, such as orange juice, broccoli, or strawberries.
  • Eat a well-balanced diet, including fruits, vegetables, whole grains, calcium-rich foods, lean meats, and a variety of cooked seafood (excluding fish high in mercury, such as swordfish and shark).
  • Drink additional fluids, water especially.

Nutrition Tips During Pregnancy

Foods to Avoid

Several substances can harm a growing fetus. Therefore, women need to avoid them throughout a pregnancy. Some are so dangerous that a woman should avoid them even if she suspects that she might be pregnant. For example, consumption of alcoholic beverages results in a range of abnormalities that fall under the umbrella of fetal alcohol spectrum disorders. They include learning and attention deficits, heart defects, and abnormal facial features. Alcohol enters the unborn baby via the umbilical cord and can slow fetal growth, damage the brain, or even result in miscarriage. The effects of alcohol are most severe in the first trimester when the organs develop. As a result, there is no safe amount of alcohol that a pregnant woman can consume. Although pregnant women in the past may have participated in behavior that was not known to be risky at the time, such as drinking alcohol or smoking cigarettes, today, we see that it is best to avoid those substances altogether to protect the health of the unborn baby.


Pregnant women should also limit caffeine intake, which is found in coffee and tea, colas, cocoa, chocolate, and some over-the-counter painkillers. Some studies suggest that very high amounts of caffeine have been linked to babies born with low birth weights. The American Journal of Obstetrics and Gynecology released a repo thatch found that women who consume 200 milligrams or more caffeine a day (which amounts to 10 ounces of coffee or 25 ounces of tea) increase the risk of miscarriage. Consuming large quantities of caffeine affects the pregnant mother and leads to irritability, anxiety, and insomnia. Most experts agree that small amounts of caffeine each day are safe (about one 8-ounce cup of coffee a day or less). However, that amount should not be exceeded.

Foodborne Illness

For both mother and child, foodborne illness can cause significant health problems. For example, the foodborne illness caused by the bacteria Listeria monocytogenes can cause spontaneous abortion and fetal or newborn meningitis. According to the CDC, pregnant women are twenty times more likely to become infected with this disease, known as listeriosis, than nonpregnant, healthy adults. Symptoms include headaches, muscle aches, nausea, vomiting, and fever. If the infection spreads to the nervous system, it can result in a stiff neck, convulsions, or disorientation feeling. Foods that are more likely to contain the bacteria should be avoided are unpasteurized dairy products, especially soft cheeses, smoked seafood, hot dogs, paté, cold cuts, and uncooked meats. To avoid consuming contaminated foods, pregnant or breastfeeding women should practice food safety guidelines. It is always essential to avoid consuming contaminated food to prevent food poisoning. This is especially true during pregnancy. Heavy metal contaminants, particularly mercury, lead, and cadmium, pose risks to pregnant mothers. As a result, vegetables should be washed thoroughly or have their skins removed to avoid heavy metals.

Pregnant women can eat fish, ideally 8 to 12 ounces of different types each week. Expectant mothers can eat cooked shellfish such as shrimp, farm-raised fish such as salmon, and a maximum of 6 ounces of albacore or white, tuna. However, they should avoid fish with high methylmercury levels, such as shark, swordfish, tilefish, and king mackerel. Pregnant women should also avoid consuming raw shellfish to avoid foodborne illness. The Environmental Defense Fund eco-rates fish to provide guidelines to consumers about the safest and most environmentally friendly choices. Visit the FDA for more information https://www.fda.gov/food/consumers/advice-about-eating-fish.

Best Seafood Choices


Food Cravings and Aversions

Food aversions and cravings do not significantly impact unless food choices are minimal. The most common food aversions are milk, meats, pork, and liver. It is not harmful to most women to indulge in the occasional craving, such as the desire for pickles and ice cream. However, a medical disorder known as pica willingly consumes foods with little or no nutritional value, such as dirt, clay, and laundry starch. In some places, this is a culturally accepted practice. However, it can be harmful if these substances take the place of nutritious foods or contain toxins.

Physical Activity during Pregnancy

For most pregnant women, physical activity is a must and is recommended in the 2015 Dietary Guidelines for Americans. Regular exercise of moderate intensity, about thirty minutes per day most days of the week, keeps the heart and lungs healthy. It also helps to improve sleep and boosts mood and energy levels. Also, women who exercise during pregnancy report fewer discomforts and may have an easier time losing excess weight after childbirth. Brisk walking, swimming, or an aerobics class geared toward expectant mothers are all great ways to get exercise during pregnancy. Healthy women who already participate in vigorous activities, such as running, can continue doing so during pregnancy, provided they discuss an exercise plan with their physicians.

However, pregnant women should avoid pastimes that could cause injuries, such as soccer, football, and other contact sports, or activities that could lead to falls, such as horseback riding and downhill skiing. It may be best for pregnant women not to participate in particular sports, such as tennis, that require them to jump or change direction quickly.

Complications during Pregnancy

Expectant mothers may face different complications during their pregnancy. About 4 percent of pregnant women suffer from a condition known as gestational diabetes, which is abnormal glucose tolerance during pregnancy. The body becomes resistant to the hormone insulin, enabling cells to transport glucose from the blood. Gestational diabetes is usually diagnosed around twenty-four to twenty-six weeks, although the condition can develop later into a pregnancy. This disease’s signs and symptoms include extreme hunger, thirst, or fatigue. If blood sugar levels are not adequately monitored and treated, the baby might gain too much weight and require a cesarean delivery. Diet and regular physical activity can help to manage this condition. Most patients who have gestational diabetes also require daily insulin injections to boost glucose absorption from the bloodstream and promote glucose storage in glycogen in the liver and muscle cells. Gestational diabetes usually resolves after childbirth, although some women who suffer from this condition develop Type 2 diabetes later in life, mainly if they are overweight.

Learning Objectives

  • Identify key nutrients required before conception. (MCCCD Competency 4)
  • Learn how nutrient needs change during pregnancy. (MCCCD Competency 4)
  • Identify optimal weight gain during pregnancy. (MCCCD Competency 9)
  • Discuss the health complications associated with underweight and overweight mothers.(MCCCD Competency 9)
  • Discuss the health consequences of gestational diabetes. (MCCCD Competency 9)
  • Identify foods and beverages to avoid during pregnancy and the health impact for mother and child. (MCCCD Competency 5)



Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Nutrition Essentials Copyright © 2020 by Stephanie Green and Kelli Shallal is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

Share This Book