Chapter 4.2 – Problems in Prenatal Development

Losing A Baby Miscarriage – when the developing baby dies prior to the 20th week of pregnancy Fairly common 15% of recognized pregnancies end in miscarriage The cause is usually not known

Losing A Baby Stillbirth – when the developing baby dies after the 20th week Occurs in about 1% of pregnancies Most common causes are problems with the placenta, abnormal chromosomes, poor growth, and infections.

Dealing With Grief The loss of a child can be very unexpected and painful Often go through stages of grief similar to those experienced by the loss of a child that was already born May feel alone or may blame themselves Most cases – the death was completely out of the parents’ control Still able to healthy children later on

Birth Defects Birth Defect – a serious problem that threatens a baby’s health, and is present at birth. Approximately 120,000 babies are born each year in the United States with a birth defect. Scientists and medical professionals are working hard to understand the causes of birth defects.

Types and Causes of Birth Defects Not all birth defects are obvious at birth Some may cause an abnormality in the structure of the body Some may cause one or more systems of the body to not function properly Scientists do not full understand the causes for most birth defects, but they have found four main causes.

Four Main Causes of Birth Defects Factors in the environment Hereditary factors Errors in chromosomes A combination of environmental and hereditary factors

Environmental Causes of Birth Defects The nutritional balance of the mother’s diet Any diseases or infections the mother has during pregnancy Harmful substances the mother consumes such as alcohol, over-the-counter medications, tobacco, and illegal drugs Some medicines that benefit the mother but hurt the baby Air pollution Exposure to X-rays and high levels of radiation, or to certain chemicals such as solvents and pesticides, especially in early prenancy.

Hereditary Causes Every person has approximately 20,000 to 25,000 genes that determine traits Genes direct the growth and development of all the body systems Recessive inheritance – when a child receives two copies of a faulty recessive gene that causes some type of birth defect Tay-Sachs disease Cystic Fibrosis Dominant inheritance – when a child receives one defective dominant gene Huntington’s disease – does not appear until middle age

Errors in Chromosomes Several types of birth defects are caused by problems in the number or structure of chromosomes. An error may occur when an egg or sperm cell is developing. Can cause a baby to have too many or too few chromosomes Or have broken or rearranged chromosomes Down Syndrome – an extra copy of chromosome 21

Interaction of Heredity and Environment Some birth defects are caused by a combination of heredity and environment Child may inherit a tendency that may later lead to a heart defect If a factor such as drug use or a virus affects the baby during pregnancy it will have the heart defect If the baby didn’t inherit the gene and get exposed to the drug or virus then it wouldn’t have the heart defect. Examples: Cleft lip, cleft palate, spina bifida

Prevention and Diagnosis of Birth Defects Quit smoking and drinking is there is a possibility of pregnancy Visit the doctor for prenatal care Avoid alcohol, drugs, and tobacco the entire pregnancy Only take medications approved by doctor Genetic Counseling Prenatal Testing

Genetic Counseling Some family doctors may be able to perform genetic counseling but usually referred to a genetic counselor Examined by genetic counselor: Family History Medical History Diseases Causes of death in the family Physical Exam Blood samples Body tissue samples

Prenatal Tests Alpha-fetoprotein (AFP) Ultrasound Amniocentesis Chronic Villi Sampling New Prenatal Diagnosis