PSY 226 CONCEPTION PRENATAL DEVELOPMENT AND BIRTH Learning

PSY 226 CONCEPTION, PRENATAL DEVELOPMENT AND BIRTH

Learning Objectives • Know the basics of how development proceeds during the first 10 months of gestation – Zygote, Fetus, and Embryo • Describe key risks to the child during prenatal development (i. e. , teratogens) and some major causes and consequences – Describe key prenatal drain development events – Describe how time and timing are important

Chronosystem: Changes between 1970 & 2005 in the Age When Women Have Their First Child

Prenatal Development: The Beginning • Fertility – Main factors affecting (in)fertility include health, lifestyle, and age – Age-related decline: women ≈ 32, men ≈ 35 – Treatments fertility drugs, artificial insemination, IVF, surrogate mother • Gestation – period from conception to birth

First 2 weeks: The Zygote • First 2 weeks – Fertilization, fused sperm and egg cells are transformed into a new cell known as a zygote Nuclei fuse: 23 chromosomes each – Rapid cell division and the beginning of differentiation • No change in mass. How is this possible? – Week 2: zygote implants into the nutrient-rich uterus

Weeks 3 -8: The Embryo • Implantation Marks the Beginning of the Embryonic Period – 2 -4 weeks • • Neural tube begins to form Organs begin to develop and function Heart starts beating Sex organs form and begin differentiation – Neurogenesis • 250, 000 neurons generated per minute during gestation! • 400, 000 neurons generated per day! – 8 weeks: Embryo is 1 inch long and weighs 1 gram

Differentiation • Cephalocaudal means “head to tail” • Proximodistal means “near to far” POP QUIZ! According to the principle of cephalocaudal development, what order will these structures develop and differentiate? FEET THIGH CALF

Week 8 to Birth: Fetal Period • Growth! Size of fetus increases twentyfold • By 6 mo. neurogenesis (development of new neurons) in the brain is nearly complete

Fetal Stage Developments • Second Trimester – Organ system development – Cycles of sleep and wake – Eyes open/close, able to perceive light – Fetal movements can be felt around 4 months – “Age of viability” is 22 -25 weeks • 50% could survive pending quality medical care

Fetal Stage Developments • Third Trimester – Heart and lungs mature – Physical activity • • Feel “kicking” with feet Turn somersaults that can be felt Turn upside down around 7 months Prenatal activity level predicts postnatal motor development – Hearing • Able to discriminate pitch

Early Learning and Memory De. Casper and Fitch (1980) • “The Cat in the Hat” – 2 x day for 6 weeks during the last trimester (≈ 5 hours) – A pacifier that senses the rate of sucking is used. A change in sucking shows the child’s preference. • Post-Natal Results with Newborns – Preference for mom’s voice over dad’s voice or other females – Preference for mom reading the “The Cat in the Hat” over another children’s book No Mozart Effect

Prenatal Brain Development LET’S TAKE A CLOSER LOOK

Protecting the Fetus • 95% of babies are born normal and healthy – Most genetic malformations are eliminated before birth • Unhealthy sperm do not make it to the egg • 50% of zygotes never implant and are spontaneously aborted

Sensitive Periods are Heightened Times of Influence to Environmental Stimuli Damage is worse when organ/limb is developing most rapidly. Earlier in prenatal development tends to be more risky • 3 -6 weeks CNS and Heart • 4 -10 weeks limbs, eyes, ears • 5 -11 weeks teeth, palate, genitals Chronosystem: Timing of a teratogen can be more important than its occurrence.

What about E-Cigs? England, L. J. , Bunnell, R. E. , Pechacek, T. F. , Tong, V. T. , & Mc. Afee, T. A. (2015). Nicotine and developing human: A neglected element in the electronic cigarette debate. American Journal of Preventive Medicine, volume in press, 1 -8.

Teratogens Environmental substances that negatively affect fetal development CIGARETTES COCAINE MARIJUANA ALCOHOL HIV LEAD/ MERCURY 2: 07

Teratogens: What would you say to future parents? • Identify risks to fetus? – 2 -3 developmental outcomes. – Is everyone at equal risk? – Are there sensitive periods? Make a slogan about what parents can do to reduce risks or promote health during prenatal development.

Some Inter-related Contributing Causes • Wanting to be a Parent – Unexpected early childbearing • Prenatal Care – Predicts preterm births for those under age 18 – Awareness/education – Health insurance – Availability of medications and vaccines (developing countries) • Poverty • Health – Eating healthy; mother is healthy weight • Stress – Predicts smoking and drinking – Inadequate sleep, exercise

http: //www. cbsnews. com/news/depressiona-risk-during-pregnancy/ What about LEGAL drugs? 4: 30

Resources for Further Exploration • The world of the embryo – http: //www. visembryo. com/ • Questions first-time expectant fathers often have but never ask (out loud) – A closer look on p. 93

Learning Objectives • Know the basics of how development proceeds during the first 10 months of gestation – Zygote – Fetus – Embryo • Describe key risks to the child during prenatal development (i. e. , teratogens) and some major causes and consequences – Describe prenatal brain development events – Describe how time and timing are important

VIDEO: Prenatal Assessment 5: 30

Monitoring Prenatal Development • Ultrasound imaging – High frequency sound waves are used to reflect an image called a sonogram • Chromosomal malformations – Caused by mutations or accidents during meiosis – Down Syndrome • “Trisomy 21” • Risk influenced by age of mother • Recessive genes – Most genetic disorders are carried on a recessive gene (e. g. , Sickle cell; Hemophilia)