Prenatal Development Problems

Losing a Baby Miscarriage – before 20 weeks 20% of all pregnancies end in miscarriage Stillbirth – after 20 weeks Effects on parents Feel like they lost a child who was born Many miscarriages and stillbirths occur naturally

Birth Defects 3 out of 100 children in U.S. Vary in degree of severity Mild to severe Present at birth to develop months later Correctible to lifelong Effect body parts, organs, or systems Possibility of death

Causes of Birth Defects 60% of birth defect origin is unknown Four main causes Environment Hereditary Chromosome Errors Interaction of Hereditary and Environment

Environmental Causes All body systems developed within the 1st few weeks Nutrition Disease or infection of mother Harmful substances Medicines Outside hazards such as radiation

Hereditary Causes 5-6 defective recessive genes per person 2 defective recessive genes = birth defects 1 defective dominant gene = birth defect Some defective genes only affect one sex Hemophilia Color blindness

Interaction of Heredity and Environment Child inherits the tendency for a disease and Environmental factors affect development of the child Similar to a crack in the foundation and then a hurricane or tornado hits, the house is weaker to begin with

Errors in Chromosomes Chromosomal defects are not inherited Result of one extra or one missing chromosome Most common is down syndrome

How does having a child with a birth defect affect the child and the family?

Diagnosis/Prevention Genetic Counseling Done by family doctors or specialists Need family medical history Information on previous pregnancies Physical examinations Laboratory tests Statistical analysis

Diagnosis/Prevention Prenatal Tests Diagnose more than 100 kinds of birth defects Three main procedures Ultrasound Amniocentesis Chorionic villi sampling

Ultrasound Sound waves produce a video image of the child Detects skeletal and organ defects Confirms due date Detects twins No risk to baby or mother

Amniocentesis Withdraw a sample of amniotic fluid Detects birth defects and health problems Down syndrome – mother over 35 Tests the baby’s cells that are in the amniotic fluid using a needle 1 in 200 women with amniocentesis end up miscarrying

Chorionic Villi Sampling Samples tissue from membrane encasing the fetus Insert tube through the vagina Snip or suction cells off the membrane Much higher risk of miscarriage or birth defects Tests for same diseases as amniocentesis