 humans or mammals. We all learn this in elementary school. We also learned that, as in mammal, we give birth to live children rather than laying an egg. Part of the reason the child develops inside the mother is to protect it from being harmed by the external environment. This means that the developing child is protected from all unwanted environmental hazards, right? The environment inside the uterus where the unborn child is developing is called the prenatal environment. Inside the uterus, the developing embryo and fetus are protected. The unborn child receives all it needs from the mother, including the nutrients that keep it healthy. The placenta is a temporary organ that joins the mother and fetus. The placenta attaches to the mother's uterus and to the unborn child through the umbilical cord. It transfers oxygen and nutrients from the mother to the fetus and allows waste products to be eliminated from the fetus. This sounds like a pretty sheltered environment for an unborn child. Let's consider our question again. Is the developing child protected from all unwanted environmental hazards? Unfortunately, the answer to this question is no. Up until the 1960s, it was believed that the placenta also acted as a filter to help keep anything unwanted or harmful from affecting the baby. We now know that potentially harmful substances can cross the placenta and be transferred to the developing child from the mother. While the prenatal environment protects the embryo and fetus from a great many dangers, it cannot protect the unborn child from everything that the mother comes into contact with. There are many potential hazards in the prenatal development of an unborn child. Many of these potential hazards are related to drug, alcohol or tobacco use. Alcohol, for example, can quickly cross the placenta and enter the unborn child's bloodstream in the same levels that it is in the mother's blood. Women who drink alcohol during pregnancy put their child at risk for fetal alcohol syndrome. This is a set of birth defects and disabilities related to alcohol consumption during pregnancy. Tobacco use during pregnancy can cause low birth weight and has been linked to higher rates of respiratory problems in children. Women who smoke are advised to stop if they discover they are pregnant or trying to become pregnant. The use of illegal drugs can cause a variety of concerns for the health of an unborn child. Prenatal development can be slowed, birth defects or death of the unborn child can occur and there is a higher risk for premature birth. Also, a child can even be born with addiction. It may seem obvious that illegal drug use can be harmful to an unborn child, but store bought or prescription medications can be a hazard as well. A caregiver can help determine the benefit of a medication and whether it is greater than the risk that it may pose to the unborn child. The use of any medication that is a known teratogen should be avoided during pregnancy. A teratogen is a substance known to potentially cause a birth defect or cause a pregnancy to end. Remember when we mentioned that before the 1960s it was believed that the placenta affected the developing child from harmful substances? The common use of the prescription drug thalidomide for morning sickness during pregnancy changed this idea. A large number of infants with birth defects were born to women who were given this medication during pregnancy. Because of this, we now know that medications can have harmful effects on the prenatal environment. Maternal diseases and environmental concerns are also factors that can harm prenatal development. Maternal diseases and infections can produce defects. Prenatal development can be impacted by factors such as RH factor incompatibility, high blood pressure, diabetes, rubella, and some sexually transmitted diseases. What effect maternal diseases could have is dependent on the stage of prenatal development in which they occur and how long the condition lasts. An embryo or fetus can be endangered by other hazards in the environment as well. Radiation, mercury, lead, carbon monoxide, or pollutants such as toxic waste can endanger prenatal development. One reason proper prenatal care is important is that it can greatly reduce the risk of hazards to the prenatal environment. A health care provider can give advice about what could be harmful to an unborn child or what to do if the unborn child may have been exposed to something harmful in its development. This is important if a woman wants to give birth to a healthy baby. Prenatal care from a health care provider also monitors the progress of a woman's pregnancy. This care helps spot any potential problems as soon as possible and helps manage any issues that may occur. Like all mammals, human babies develop inside their mother. The environment inside the uterus where the unborn child is developing is called the prenatal environment. The mother and fetus are connected by a temporary organ called the placenta. It attaches to the mother's uterus and to the unborn child through the umbilical cord. It transfers oxygen and nutrients from the mother to the fetus while allowing the fetus to eliminate waste. Inside the uterus the unborn child is protected but harmful substances can still cross the placenta and cause harm. There are many potential hazards to the prenatal development of an unborn child. Many of these potential hazards are related to drug, alcohol or tobacco use. An example is fetal alcohol syndrome. Maternal diseases and environmental concerns such as exposure to radiation are also hazards. Proper prenatal care can greatly reduce the risk of hazards to the prenatal environment.