Ovulation & Conception
● Ovulation - Release of an ovum (egg) into the female reproductive tract -
occurs midway through the menstrual cycle (about 14 days into a 28-day
cycle)
○ Ovum dies within 24 hours unless fertilized
● Pregnancy weeks are counted based on the first day of last known
menstrual cycle; 4 weeks is the EARLIEST you can know!
Germinal Period
● Egg is fertilized (Conception) and becomes a zygote (23 matched pairs of
chromosomes)
○ Zygote continues to divide (mitosis), growing into a Blastocyst
(future Embryo), and Trophoblast (future Placenta)
■ Eventually attaches to the uterine wall approximately 10-15
days after conception ; If it attaches to an incorrect location, it
becomes an Ectopic Pregnancy
● This period of development occurs during the first two weeks after
conception
● Trophoblast begins to produce hCG - pregnancy hormone that
eventually becomes detectable after four weeks
Embryonic Period
● After implantation to the uterine wall, the ball of cells is called an embryo
○ Embryonic Period lasts from about 2-8 weeks post-conception
(4-10 weeks pregnant)
● 3 Layers of Cells Develop
○ Endoderm - Internal Organs
○ Mesoderm - Vascular System, Musculoskeletal systems
○ Ectoderm - Skin, nervous system and brain, sensory receptors,
eyes, ears
Development of Embryo
● Trophoblast grows into life support system from embryo
○ Placenta grows larger, stronger, more refined
○ Umbilical cord develops; connect embryo to placenta
■ Provides food, liquid, oxygen; removes waste
■ Secretes hormones to sustain embryonic growth
● Basic body structures develop
○ From TOP TO BOTTOM (head first, feet last); prioritizes resources
○ From INSIDE TO OUTSIDE
■ Internal organs; torso before limbs
■ Arms & legs before hands & feet
Development of Fetus (Fetal Phase)
● Period lasts from about 2 months post-conception until birth (largest period)
● Third Month
○ Head is large, but growing slowly
○ Eyes move into place
○ Genitalia form and can be visible via ultrasound
○ Reflexive and muscular movement (although not felt)
● Fourth Month
○ Rapid growth in length (height)
○ Slow weight increase
● Fifth Month
○ Rapid growth in length (height) continues
○ Fine hair growth covers body; Linugo
○ Movement often felt by mother
● Sixth Month - (Avg. Weight 1lb. 13 oz.) --- POTENTIAL START OF VIABILITY
○ Skin red, wrinkled; body lean; fingernails evident
○ Development of Respiratory and Central Nervous System
● Seventh Month - (Avg. Weight 2 lb. 14 oz.)
○ Eyes open, eyelashes and toenails form
○ Body fills out; Most organs done except lungs → Lungs need a LOT of
time
● Eighth Month - (Avg. Weight 4lb. 10 oz.)
○ Skin becomes pink, smooth; fat grows benath skin
○ Testes descend in males
Teratogens & Fetal Development
● Teratogen - Any substance or agent that can disrupt development or
cause a defect
● Critical Factors
○ Dose - Amount of exposure; more exposure → greater effect
○ Genetic Susceptibility - Metabolism, vulnerability, sex (males
more susceptible than females)
○ Time of Exposure - Earlier exposure is typically more impactful
Teratogens : Medications
● Prescription & OTC Medications
○ Accutane, antidepressants, antibiotics
○ Aspirin (high doses), Ibuprofen
● Psychotic Drugs
○ Caffiene - Inconsistent results, ACOG and others recommend
limiting caffeine during pregnancy (1-2 cups per day)
○ Alcohol - Heavy drinking can lead to Fetal Alcohol Spectrum
Disorders
■ Birth defects, intellectual and learning disabilities
● No amount of alcohol is considered safe; too little
information
○ Nicotine - Preterm birth, low birth weight, SIDS
■ E-cigarettes and second-hand smoke are also risks
○ Marijuana - Research is NEW, evidence of links to low birth rate,
disabilities
■ Use during pregnancy is increasing, perceptions vary
Teratogens : Illicit Drugs
● Cocaine, Meth, Heroin
○ Use during pregnancy is linked to lower birth rate, physical, motor,
cognitive developmental delays or deficits in infants and/or later in
childhood
■ Some experience withdrawal symptoms after birth!
■ Difficult to interpret outcomes due to different variables
Blood Type Incompatibility
● Rh Factor - Positive or Negative
○ Problems arise when mother is Rh-Negative and the Infant is
Rh-Positive!
■ Mother’s body produces antibodies that can attack the fetus,
causing many problems including miscarriage or stillbirth
● First Rh-Positive fetus is usually unaffected, but
subsequent Rh-Positive babies are more likely to be
affected
■ Rhogam Vaccine - Given during pregnancy and shortly after
babies’ birth to prevent buildup of antibodies that might
affect future pregnancies
Nutrition & Health
● Maternal Diet & Nutrition
○ 100% of fetus’ nutrition comes from Maternal blood source!
○ Critical need for overall caloric intake, beware of potential
toxins (some fish) or pathogens (Listeria- cheese, deli meat)
○ Specific need need for Folic Acid to prevent Neural Tube Defects
○ Complete nutrition during pregnancy, but also in months/years prior
to conception
● Maternal Disease
○ Some STIs can have devastating impacts on fetal or infant
outcomes; screening during prenatal care
○ Syphilis - blindness in infants
○ Genital Herpes - death, brain damage, C-section used during active
outbreak to prevent spread of the virus to infant
○ HIV/AIDS - can be transmitted during pregnancy, birth, or through
breast milk
Age of Parents
● Maternal Age
○ Risks at two ages - Adolescence and after age 35/40
○ Infant mortality rate is 2x higher for adolescent mothers,
likely due to lack of prenatal care
○ Risk of low birth weight, stillbirth increases after 35 and gets
worse with age
○ Risk of Down Syndrome (Trisomy 21 - an extra chromosome
on the 21st pair); increases after 40
● Paternal Age
○ Risks increase with age, particularly over 40 for autism,
miscarriage
Postnatal Care
● Apgar Scale - assessed at one minute and five minutes after birth
○ Immediate assessment to determine status of infant and whether
emergency care is needed (NICU)
● Brazelton Scale & NNNU - More sensitive measures of overall functioning
taken after 24 hours or later
➔ Pre-Term Infants - Born before 37 weeks Gestation
➔ Low Birth Weight Infants - Weigh less that 5.5lbs at birth
◆ Can be premature or small-for-date
➔ NICU - Neonatal Intensive Care Unit: Infants born with severe
complications such as prematurity, low-birth weight, breathing or feeding
problems
◆ Kangaroo Care - Skin-to-skin contact for several hours, when
possible. Rest of treatment time in Isolette; regulates physiological
processes - breathing, heart rate
