Prenatal Development

Female Reproductive Organs

Conception

Every 28 days, an ovum, lasts 24 hoursMillions of sperm, viable for up to 6 daysConception in the fallopian tube

Tubal pregnancy

Conceptions most likely: on day of ovulation or the two days preceding ovulation

Conception

The Period of the Zygote or the Germinal Stage

First Two weeks following conceptionFrom fallopian tubes to attachment to

the uterine wallBlastocyst, 60-70 cells, 4th day

Embryonic disk (organism)Outer Ring (umbilical cord & placenta)

Implantation between days 7 & 9

Zygote Period Continued

Amnion Membrane, amniotic fluidYolk sack produces blood cellsChorion MembranePlacenta - Food, oxygen, wasteUmbilical cord30% of zygotes do NOT survive

The Period of the Embryo

From 2nd week through 2nd monthVery rapid prenatal developmentEmbryonic disk folds into three layers

Ectoderm - Nervous system (fast develop.) & skinMesoderm - skeleton, muscles, circulationEndoderm - Digestion, lungs, urinary tract

5.5 Weeks 9 Weeks

Embryonic Period Cont.

Many body parts develop the 2nd monthFingers, toes, facial features, nervous system cells

fire, teeth buds have formed

Embryo’s posture becomes uprightThe embryo can moveThe embryo responds to touch (mouth & feet)

11 Week Fetus

The Period of the Fetus

Growth and finishingThird month

Organs, muscles & nervous system organize and connect

External genitals – visible with ultrasoundEnd of first trimester

Second Trimester

13-24 weeks - first movement feltVernix covers fetus, prevents chappingLanugo hold vernix to skinTrillions of brain neurons produced

Stimulated by sound and light

Third TrimesterAge of viability - 22 to 26 weeksCerebral cortex enlarges

Responsive to external stimulation

Fat layer develops for temp. reg.Moves to the upside-down positionFetus moves less

Teratogens

Environmental influences or agents that can damage the developing organism

Influence of Teratogens

Larger doses, over time, more negative

Genetics can help or hinder teratogens

Several negative factors increase impact

Sensitive periods especially important

Embryonic period most susceptible

Physical and psychological effects

DrugsThalidomide –

sedative - 1960’s

Aspirin - low birth weight, infant deathPoor motor develop., lower IQ

Heavy caffeine use - miscarriagePremature births, irritability

Illegal Drugs

Cocaine, heroin, methadonePrematurity, low birth weightPhysical defects, breathing problems,Drug addiction & death

Cocaine - lasting difficultiesGenital, urinary tract, kidney, heart deformitiesBrain seizures

Crack babies

Lowest birth weightCentral nervous system damageFathers on cocaine may pass it on

Multiple harmful effects of more than one drug

Tobacco use

Low birth weight and premature birthsImpaired breathingMiscarriage & infant deathPlacenta doesn’t work correctlyGreater concentration of carbon monoxidePassive smoking also injurious

Alcohol

Fetal alcohol syndrome (FAS)Large amounts of alcohol, whole pregnancyMental retardationSlow physical growthFacial abnormalities

Alcohol interferes with cell duplicationEspecially neural cells

Draws oxygen away from organism

Fetal Alcohol Syndrome

Hormones

Diethylstilbestrol (DES), 1945-70Vaginal cancerMalformation of the uterusMiscarriage, low birth weightIn males, genital abnormalities, cancer

Radiation

Hiroshima & NagasakiMiscarriage, slow physical growthUnderdeveloped brainsMalformation of skeleton & eyes

X-Rays - avoid during pregnancy

Environmental Pollutants

100,000 in common useMercury

Mental retardation, speech problemsDifficulty chewing & swallowingUncoordinated movements

Polychlorinated Biphenyl (PCB)Lower birth weight, smaller headsPoor memory, lower verbal IQ

Maternal Disease

Viruses - Most not harmfulRubella

Heart defects, cataracts, deafnessGenital, urinary & intestinal problems

HIV & AIDS20-30% Mothers pass to infantsFast growth in infantsMost survive 5 to 8 months

Maternal Disease Cont.

Herpes virusesBabies infected during pregnancy

or at birth

Bacterial & Parasitic DiseasesToxoplasmosis from meat or cats40% transmission Eye & brain damage

Positive Health Activities

Moderate, low impact exerciseHealthy diet - vitamin supplements

Malnutrition causes problemsWIC Program

Low stressIntense anxiety >> miscarriage, premature

birth, low birth weight, respiratory illness,Cleft palate & Pyloric stenosis

Rh Factor

Mother Rh -, father Rh+, Child Rh+Antibodies against foreign Rh proteinRhoGam within 72 hours

Prenatal Health Care

Every month of pregnancy visit MD2X/Month for the last two months

Watch For . . .

Diabetes complicationsToxemia

Get vaccinations before becoming pregnant

Prenatal Courses

Information: Birth & ParentingExercisesSupport