Child Development From Infancy to Adolescence. Laura E. Levine
for preventative care are just some of the things that can help improve this situation.
Maternal Diet
One of the best ways to ensure a healthy pregnancy is for a mother to have a healthy diet. Because the developing baby is so small relative to the size of the mother, an average of 300 extra calories a day is all that is needed to support prenatal growth (Kam, 2016), with fewer calories required early in the pregnancy and more nearer the time for delivery. The recommended weight gain for women who begin their pregnancy at a normal weight is 25 to 35 pounds (ACOG, 2013). Newborns typically weigh between 5 pounds 8 ounces and 8 pounds 13 ounces (KidsHealth, 2017). The remainder of the pregnancy weight is made up of amniotic fluid, the placenta, increased fat stores in the woman’s body, and increased maternal blood volume. Infants who are born smaller than average for their gestational age are more vulnerable to infections, and those who are much larger than average increase the length of labor and risk difficulties in the delivery itself.
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A pregnant woman is “eating for two” so she should double the number of calories she consumes each day. False
When a pregnant woman has a severely restricted diet, it can affect the future health of the infant, as well as cognitive skills, problem-solving abilities, developmental levels, and behavioral functioning (Boulet, Schieve, & Boyle, 2011; Sudfeld et al., 2015). However, malnourishment is not the only developmental risk. Whether a pregnant woman’s diet is nutritionally restricted or is a more typical high-fat Western diet, it can predispose her infant to obesity later in life by affecting how the child’s metabolic system will function. In this way, maternal nutrition can contribute to what has been called a “legacy of obesity” (Parlee & MacDougald, 2014, p. 495).
Healthy eating while pregnant. Healthy eating is always important, but particularly while you are pregnant. The mother’s diet provides all the nutrients her developing child needs. Avoiding foods that can be harmful is equally essential.
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Because pregnant women need an adequate amount of vitamins and minerals, doctors usually prescribe a multivitamin or prenatal vitamin. Folic acid, one of the B vitamins, plays an important role in preventing defects of the brain and spinal cord, so the CDC (2016k) recommends that all women of childbearing age consume 400 micrograms of folic acid daily, even if they are not pregnant. This can come from foods in the woman’s diet (such as fortified breakfast cereals, beans, leafy green vegetables, and orange juice) or from a food supplement.
There also are some foods that should be avoided because of risks associated with them. For instance, luncheon meats and soft cheeses such as Brie and feta can contain bacteria (U.S. Food and Drug Administration [FDA], 2016a). Fish should be a regular part of a pregnant woman’s diet, but certain fish, including shark and swordfish, can have high levels of mercury or industrial pollutants and should be avoided (FDA, 2017b). Although there has been some concern about the relationship between caffeine consumption and preterm birth, a meta-analysis of this research did not support this concern (Maslova, Bhattacharya, Lin, & Michels, 2010). A moderate caffeine intake of one 12-ounce cup of coffee per day is usually considered safe (American Pregnancy Association, 2016a). Because caffeine also can come from tea, soda, chocolate, bottled water, and energy drinks, caffeine from these foods should be taken into account when figuring daily caffeine consumption.
Exercise
Pregnant women benefit from an appropriate level and type of exercise. It can help relieve some of the normal discomforts associated with a pregnancy, such as backaches or fatigue, and improves mood and sleep quality (American Pregnancy Association, 2016b; Mayo Clinic, 2015b). It also helps prevent excessive weight gain and strengthens and prepares the woman’s body for labor.
A woman should consult her physician about her particular situation, but women who were physically active before they became pregnant can usually continue moderate levels of the same activity while pregnant, although some adjustments will need to be made. Pregnancy hormones make joints and muscles more flexible, a woman’s center of gravity shifts as her belly gets bigger, and, of course, she weighs more (American Pregnancy Association, 2016b), so exercise needs to be modified to accommodate these physical changes. For women who have not been physically active before, low-impact activities, such as yoga and walking, are better choices than ones that involve a chance of falling or too much bouncing or jumping.
Yoga while pregnant. Moderate exercise while a woman is pregnant can be beneficial to her health and the health of her baby. It relieves some of the discomforts of being pregnant, while keeping the mother fit and strong. It also helps to prepare her body for labor and delivery.
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Teratogens
Even with a healthy diet, good prenatal care, and plenty of exercise, a number of factors can have a negative impact on prenatal development. Agents that can cause malformations in an embryo or a fetus are broadly referred to as teratogens. They include diseases a mother has or contracts during her pregnancy, things she ingests, and toxins in the environment. Because there are so many potential teratogens, we can talk only briefly about some of the most common ones in this chapter.
Teratogens: Agents that can disrupt prenatal development and cause malformations or termination of the pregnancy.
Each teratogen has a specific effect on the developing embryo or fetus and can result in a structural abnormality, such as missing or malformed limbs, or a functional deficit, such as hearing loss or intellectual disability. Figure 4.5 shows the sensitive periods for the impact of various teratogens on development. The level of the impairment can range from mild to severe. The nature and magnitude of the effect depends on when in the prenatal period the fetus or embryo is exposed to the teratogen, the amount or dosage of the exposure, and the length of time the exposure continues. For example, an exposure that could end a pregnancy if it occurred early in the germinal stage might produce serious physical defects if it occurred during the embryonic stage but much less severe defects if it occurred late in the fetal stage.
Figure 4.5 Sensitive periods in prenatal development.
Source: Moore, K. L., & Persaud, T. V. N. (2003). The developing human: Clinically oriented embryology (7th ed.). Philadelphia, PA: W. B. Saunders..
The effect when a woman contracts rubella or German measles at different points in her pregnancy is a good illustration of this point. The effect on an adult woman is rather mild, but the effects on her pregnancy can be devastating. Exposure in the first 11 weeks results in birth defects that include significant problems with vision, hearing, and heart function in 90% of cases, while exposure later in the pregnancy leaves 20% of infants with congenital defects (Reef & Redd, 2008). Although rubella is a relatively rare disease in the United States where children are routinely vaccinated against it, the World Health Organization (2014) estimates that worldwide 110,000 babies are born with the symptoms of a prenatal rubella infection each year. For this reason, it is important that children continue to be vaccinated for this disease so that women are not exposed to the virus during their pregnancy.