Problems in Prenatal Development

Miscarriage and Birth Defects

Losing a Baby• Miscarriage: If the developing baby dies

before the 20th week of pregnancy.

15 to 20 percent of recognized pregnancies end in miscarriage.

• Stillbirth: If the baby dies after the 20th week of pregnancy

This occurs in about 2% of pregnancies

common causes: abnormal chromosomes

poor growth

infections

problems with the placenta

Dealing with Grief

• Parents go through stages of grief– Similar to losing a child that has been born

Types of Birth Defects

• Birth Defects: babies that are born with problems that threaten their health or their lives.

• Hundreds of types

• Some mild - barely noticeable

• Some severe - lifelong

• Some birth defects cause an abnormality in the structure of the body.– Ex. Misshapen foot

Missing finger

• Others cause one or more body systems not to function properly– Ex. Blindness

Mental retardation

• Some birth defects are apparent at birth

• Others are not discovered until months or years later

Achondroplasia Huntington’s Disease

Cerebral Palsy Hydrocephalus

Cleft Palate Marfan Syndrome Clubfoot Muscular Dystrophy

Cystic Fibrosis Phenylketonuria (PKU)

Down Syndrome Progeria

Fifths Disease Rh Disease

Fragile X Syndrome Sickle Cell Disease

Gastroschisis Spina Bifida

Hemophelia Tay-Sachs Disease

Causes of Birth Defects

• Environmental Causes

**THE BABY’S ENVIRONMENT**

(womb)

- poor nutrition of mother

- diseases or infections of mother

- harmful substances taken by mother

ex: alcohol, drugs

- medicines taken by mother

- exposure to hazards

ex: X rays, chemicals

• Hereditary Causes:– When a child inherits a defect from its parents.

• Ex: cystic fibrosis - If both parents

pass on a recessive gene for

the disease, the baby will get

the disease.

• Errors in Chromosomes:– Due to problems in the number or structure of

chromosomes. Not hereditary, because neither parent has the abnormal chromosome.

– Ex. Down Syndrome - an extra copy of chromosome 21.

• Interaction of Heredity and Environment:– Some birth defects are caused by a combination of

heredity and the environment. For example, a child may inherit a tendency for a birth defect. If an environmental factor exists, the baby will have the defect.

– Ex. Cleft palate and cleft lip

Spina bifida

Prevention & Diagnosis of Birth Defects

• Prospective parents should get regular health checkups.

• Avoid smoking, drugs & alcohol

• Genetic Counseling:– Genetic counselors can inform couples of their

chances of having a child with certain birth defects. They will not be told what to do - just what the options and risks are.

Prenatal Tests• Alpha-fetoprotein (AFP):

– Blood test performed on mother• It checks the levels of AFP being

produced by the fetus. Abnormal levels can mean a birth defect.

• Ultrasound:– Uses sound waves to make a video image

of the developing baby. Some birth defects can be detected with an ultrasound picture (sonogram).

• Amniocentesis:Taking a sample of the amniotic fluid that

surrounds the developing baby. This is usually used to test for Down Syndrome when the mother is over 35.

• Chorionic villi sampling:– Takes a sample of the tissue in the placenta.

Used less often, due to greater risks.– Can be used earlier than amniocentesis.