OB lecture 1 & 2

 Terms

o Genes

 Genes are composed of DNA (hereditary material) and protein.

o Genome

 an organism’s complete set of DNA

o Genotype

 a person’s genetic makeup

o Phenotype

 refers to how the genes are outwardly expressed (i.e., eye color, hair color, height

o Dominant inheritance

o Recessive inheritance

 The traits of the recessive gene are present when both genes of the pair are recessive.

o Genetic disorders

 Genetic defects occur when there is a defected recessive gene is present and paired with a health gene but it will not express… they are 

a carrier… it won’t manifest

o if both genes are defected then the person would carry the disorder AND manifest it physically

 Sex linked disorder aka X-linked because most of the time it is found in the X chromosome

o if woman is affected she does not manifest, she is only a carrier

o men who carry it will also manifest the disorder

o ex. XX (female).. one gene is defective and replica is healthy… women will not manifest because it is paired with one 

healthy gene

 XY (male) no healthy counterpart/replica that can help, so they will manifest 

o Examples: colorblindness, balding, hemophilia (can’t clot… can’t participate in contact activities) 

o 50% chance carrier mom passes to daughters will become carriers and 50% to son who will be affected

o it is always the recessive genes that are defected not dominant

 Risk factors for genetic disorders

o Maternal age >35 increased risk of chromosomal abnormalities

 Down syndrome, deletion, translocation

o Hx of previous pregnancy resulting in genetic disorder

o Man and/or woman who has a genetic disorder

o Family Hx 

o Specific decent 

 Sickle cell – African American 

 Mediterranean fever

 Cystic fibrosis – Europeans

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 Tay-sachs – Jewish

 Why test?

o Perinatal genetic testing/early dx

o Parental decision to terminate or maintain pregnancy

o Nurse’s role in genetic counseling

 Assess s/s 

 Offer support

 Educate on procedures and tests

 Assist in value clarification

 Do not give results! But can clarify results

 Teratogens

o Smoking constricts vessels and nutrients to baby are restricted

 Baby is deprived of nutrients

 Intrauterine growth restriction (IUGR)

 Low birth weight

o Cytomegalovirus

 Increased risk for:

 Hydrocephaly

 Microcephaly

 Cerebral calcification

 Mental retardation

 Hearing loss

o Radiation

o Medication

o Raw meat

o Cats… advise to have someone else change litter… or place cat somewhere else during prenancy

o Cocaine

 Placenta can detach (most common cause of placenta abruption)

 Increased risk for:

 Heart, limbs, face, gastrointestinal tract, and genitourinary tract defects

 Cerebral infarctions

 Placental abnormalities

o Alcohol

 Increased risk of fetal alcohol syndrome occurring when the pregnant woman ingests six or more alcoholic 

drinks a

 day. No amount of alcohol is considered safe during pregnancy.

 Newborn characteristics of fetal alcohol syndrome include:

 Low birth weight

 Microcephaly

 Mental retardation

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 Unusual facial features due to midfacial hypoplasia

 Cardiac defects

o Avoid raw meat/fish

 Especially first 8 weeks of pregnancy (organogenesis period…most critical)

o EFFECTS

 Fundus is the head of the uterus

 Hormones

o GRH

o FSH

o Ovaries produce estrogen

 Regenerates or rebuilds lining of the uterus 

 Menstrual cycle

o Ovarian cycle