Before Birth: Prenatal Behavior and Development

1. Before Birth: Prenatal Behavior and Development Fogel Chapter 3 Created by Ilse DeKoeyer-Laros, Ph.D.

2. Overview Chapter 3 • Conception and Fertility • Applications: Family Planning • Developmental Processes • Individual Differences in Prenatal Development • Family and Society Experiential Exercises

3. Conception & Fertility • Conception: the union of an ovum and a spermatozoon, creating a zygote (fertilized ovum) • Spermatozoa & ova are known as gametes • Twinning happens in about 1 in 80 pregnancies • Dizygotic (DZ) or fraternal twins: two ova are fertilized and two different zygotes develop • Monozygotic (MZ) or identical twins: the fertilized zygote divides and splits into two separate zygotes Picture from: www.creative-baby-shower-ideas.com

4. Conception & Fertility Fertility: the ability to contribute successfully to fertilization or conception • male fertility begins at puberty and, for most males, lasts their entire life • female fertility lasts until menopause; ova develop prenatally but do not mature until puberty

5. Contraception & Family Planning • How many people can the earth support? • appr. 6 billion people on January 1, 2000 and by 2030, this is expected to have doubled • Family planning & contraceptives • especially important where the size of the population outstrips the ‘s ability to provide for everyone • depends on personal & cultural values and culturally adapted interventions work the best • education is a necessary ingredient in a successful family planning program

6. Teenage Pregnancies Teenage births increased until 1990s, then declined. Risks involved with teen births include • birth defects, infant death, low birthweight • teens show lower responsiveness to babies & less mutual mother-infant affection and enjoyment (compared to older mothers) Picture from: blog.nj.com/parentalguidance/health

7. Teenage Pregnancies Social systems perspective • teenage mothers are 7 times as likely to be poor before pregnancy as older mothers • teen mothers & fathers are more likely to have low academic performance & be unpopular among peers • teen marriages often end in divorce • children of teen parents are more prone to adolescent delinquency, violence, and arrest than other teens

8. Education & Contraceptionfor Youth • focus on internal locus of control, academic achievement, effective life choices, and poverty alleviation • better pregnancy outcomes with reduction of stress, social support, prenatal care, and parental involvement with the infant Prevention should begin early & involve the entire community and culture Picture from: http://gainesvillecare.org/about/nine-months.php

9. Education & Contraceptionfor Youth • 1990-2005: 50% of highschoolers engaged in sexual activity • the majority of teenagers do not have basic knowledge of sexuality, conception & contraception • more sex education is needed • Education about responsible sexuality is more effective than abstinence-only programs in preventing sexual activity & pregnancy

10. Infertility About 1 in 6 couples suffers from infertility – they are unable to conceive successfully for at least one year • female infertility is usually caused by a failure to ovulate (often treatable) or the unsuccessful journey of the ovum to the Fallopian tubes (treated by surgery and/or drugs) • male infertility is caused by potentially treatable factors (e.g., smoking ,tight underwear, hot baths or saunas); or by injuries, underdeveloped testes, and some childhood diseases

11. Enhancing Fertility • Natural methods • timing sexual intercourse around the time of ovulation • good health, weight, diet, exercise; avoiding hot tubs and saunas (males) • Medical interventions • artificial insemination • in vitro fertilization (IVF) • Some of these interventions raise ethical dilemmas and health issues

12. Prenatal Developmental Processes All cells in the body – except the gametes – have the same set of genes and chromosomes: • the genotype consists of a spiral-shaped molecule called deoxyribonucleic acid (DNA) • DNA is segmented into sections, each of which contains a different set of bases • each segment is called a gene • genes are arranged in long strings into chromosomes Picture from: http://www.coolest-gadgets.com/search/model+of+DNA+strand

13. Prenatal Developmental Processes Each of the body’s cells contains the same set of genes and chromosomes • 23 chromosomes in each gamete • 46 chromosomes (23 pairs) in other cells represent represent about 1 million bits of genetic information

14. Prenatal Developmental Processes The number of genetically different individuals is enormous • each gamete contains a slightly different set of chromosomes • the particular pair that unite for fertilization is random This rare set of twins, for example, were born to two parents of mixed race (in the UK) Picture from: www.parentdish.com

15. Prenatal Developmental Processes • Two cell division processes • mitosis: each chromosome copies itself before cell division • meiosis: cell division in the gametes, without copying chromosomes • Development of the zygote • the number of cells grows rapidly through mitosis, doubling every few hours • because mitosis is an exact copying process, each of these cells has the same genetic material

16. Prenatal Developmental Processes How can different tissues and structures develop, given identical genes in each cell? • some cells are on the surface and some on the interior: they are in contact with different environments • different environments expose the cell to different molecules moving into the cell • these compose the epigenome – biochemical markers that turn on or turn off the actions of particular genes within each cell

17. Prenatal Developmental Processes • Phenotype • the result of a constant & dynamic interaction between the genotype, the epigenome, and the environment inside and outside of the cell • Embryonic stem cells • early in the process of the formation of different regions, cells can be removed from one region and placed in an entirely different one – they take on the properties of the other cells around them

18. Prenatal Developmental Processes Even though every cell in the embryo has the same genes, because the epigenome is responsive to the local environment, different genes become active in different types of cells

19. Prenatal Developmental Processes The most common embryonic structure is a tube • in all animals, the first tube is the gut • in vertebrate animals, one of the early-forming tubular structures is the spinal cord and spine

20. Types of PrenatalDevelopmental Changes • Changes in kind • the zygote gradually differentiates into multiple kinds of tissue • certain structures emerge and then disappear • Changes in number • cell numbers increase and decrease; but increase overall • Changes in position • e.g., the heart forms near the face • Changes in size • growth varies with the time and location of the organ • Changes in shape • the organism changes from an oval shape into an elongated shape; there are also changes in the shape of cells and organs

21. Phases of Prenatal Development Human gestation lasts about 38 weeks and develops in three periods: • The period of the zygote: fertilization until implantation into the uterine wall (about 2 weeks) • The period of the embryo: implantation until the end of the 2nd month • The period of the fetus: the organism begins to resemble a human and the bones begin to harden (2nd – 9th month)

22. Phases of Prenatal Development Examples of prenatal development: • 3D slide shows at • news.bbc.co.uk/2/hi/in_pictures/3847319.stm • slideshow.ivillage.com/parenting/pregnancy/calendar/your_babys_development • 4D clips at • www.youtube.com Picture from ivillage.com

23. The Period of the Zygote At the end of the 2nd week, the zygote has developed into a blastocyst • consists of theembryonic disk, surrounded by the amniotic sac and the yolk sac • triggers the secretion of human chorionic gonadotropin (HCG) hormones that inhibit menstruation & are used in laboratory pregnancy tests

24. The Period of the Embryo The embryonic disk differentiates into three layers: • endoderm: will become the digestive, urinary, and respiratory systems • mesoderm will become the muscles, bone, circulatory system, and reproductive system • ectoderm will become the central nervous system and brain, the sense organs, and the skin, hair, nails, and teeth

25. The Period of the Embryo • Yolk sac: produces blood cells; becomes part of liver, spleen, and bone marrow • Amniotic sac: grows to cover the embryo and contains the amniotic fluid (“cushion” for the fetus) • The chorion is a membrane that surrounds all of these developments – out of its outer surface, the placenta forms as a link between the bloodstreams of mother and embryo

26. The Period of the Embryo There are rudimentary behaviors, such as heartbeats, respiration, and whole-body jerky movements • the heart is beating by the end of the 1st month • by 6 weeks, the limbs begin to differentiate; fingers & toes will appear shortly • has all of the major organs except genital organs • by 4½ weeks, the embryo has a rudimentary sensory system, but sense organs are not yet connected to nerve fibers • by 7 weeks, the embryo is responsive to touch in the mouth region and will turn its head to the side

27. The Period of the Fetus7-16 weeks In this period, spontaneous movements emerge • with maternal muscle contractions, sounds, and changes in maternal glucose & oxygen levels • become more localized and specific over time • reflexes emerge first

28. The Period of the Fetus7-16 weeks The purpose of these movements is not entirely clear. However, • preventing chicks & mice to move prenatally results in deformations and movement problems • fetal movement helps the development of nerve endings in the sensory receptors • possibly, early movements contribute to later hand preferences • early movements may help the fetus adapt to its environment

29. The Period of the Fetus7-16 weeks Physical changes • by 16 weeks, the fetus is about 3 inches & 1/2 ounce • the brain forms two hemispheres around 9 weeks • by 15 weeks, it communicates with the sense organs & muscles and begins to inhibit movement • external genitals form • testosterone in male fetuses activates genes that induce the development of external male genitals around 3 months; it may also affect prenatal brain development • female genitals do not require any specific hormone to develop

30. The Period of the Fetus17-22 weeks • subcortical & cortical cells and pathways inhibit uncontrolled, spasmlike movements Rapid brain development takes place • after 22 weeks, movements are more specialized & controlled

31. The Period of the Fetus17-22 weeks • New physical characteristics • hair on the body (lanugo) & head, eyebrows & eyelashes • skin: vernix caseosa protects the delicate skin • nails & tooth buds • At 6 months, the fetus weighs about 2 pounds; it is unlikely to survive if born prematurely • esp. if less than 600 grams or less than 24 weeks

32. The Period of the Fetus23-36 weeks • Growth: 900 grams at 24 weeks to appr. 3,500 grams (7 pounds) at 36 weeks • Active & quiet states become waking & sleeping states • sleep is divided into a period of quiet sleep and a period of active or REM sleep • the 32-week-old fetus spends about ¾ of its time in REM sleep

33. The Period of the Fetus23-36 weeks • Can feel pain between 26-30 weeks (linked to brain development) • New movement patterns • cry, grunt, yawn • by the 8th month, thumb sucking and opens eyes • grasping, postural adjustment movements • fetus can see, hear, feel, and smell • Could survive if born by about the 7th month, with intensive care

34. The Period of the Fetus23-36 weeks • Fetuses also develop the capacity to learn • distinguish voices (male & female; mother & stranger) • newborns prefer songs or stories they heard prenatally, as well as familiar smells and tastes • Prenatal learning may • serve as an early attachment mechanism • orient the baby to the postnatal environment • play a role in the development of connections between sensory, motor, and information processing areas of the brain

35. The Period of the Fetus23-36 weeks Do late-term fetuses have psychological experiences? Evidence suggests… • the ability to self-regulate by 33 weeks • beginnings of bodily self-awareness Does prenatal enrichment have a lasting effect? • there is no good evidence for this yet • still, singing, talking, and massaging can be healthy & rewarding for mother & fetus

36. The Period of the Fetus23-36 weeks See a late-term fetus moving around in the mother’s belly to the father’s voice at • www.youtube.com/watch?v=973dNQ-licM Picture from http://www.jointeffortchiro.com

37. Individual DifferencesGenetic Influences • Depend on gene-environment interaction • Genetic disorders can occur through • polygenic inheritance • dominant-recessive inheritance (e.g., PKU) • sex-linked inheritance (e.g., Fragile X syndrome) • Chromosomal disorders involve additions and deletions of chromosomes • e.g., Down’s syndrome

38. Individual DifferencesTeratogens • Environmental agents responsible for birth defects are known as teratogens • e.g., alcohol, drugs, and diseases • Effects depend on • when the exposure occurs: the earlier, the riskier • ⅔ of all birth defects occur in the first trimester • the size of the dosage & the length of exposure • longer, larger doses create the greatest risk

39. Individual DifferencesTeratogens Fetal alcohol syndrome (FAS) • mental retardation, facial abnormalities, hyperactivity, growth retardation, more premature births & miscarriages, lower birthweight, and heart defects • 1 to 3 per 1,000 births in the United States • the heaviest drinkers have a 30% higher risk of having an FAS child, but children of moderate drinkers may still develop fetal alcohol effects (FAE)

40. Individual DifferencesTeratogens Smoking • respiratory problems, birth complications, growth retardation, antisocial behavior, learning disabilities • excitability, colic and gastrointestinal symptoms in infancy & obesity, asthma and other respiratory disorders, and conduct problems in childhood • lowers boys’ sperm count and testes size when they reach adolescence • predisposes teens of both sexes to nicotine addiction • passive smoking has effects just as severe as those of direct smoking

41. Individual DifferencesTeratogens Cocaine • reduces birthweight & creates circulatory, respiratory, and urinary problems • increases the risk of Sudden Infant Death Syndrome, attentional difficulties, withdrawal, language delay, and lags in motor development • these problems may be due to other health risks (e.g., poor diet, poor prenatal care), poverty, maternal depression, family disruption, child abuse, and neglect – rather than the drug itself • alleviation of these contextual factors can in most cases eliminate the effects of the prenatal cocaine exposure

42. Individual DifferencesTeratogens Maternal Depression • estimated 9-14% of women show depression during pregnancy • up to 35% of women take psychotropic medication during pregnancy, primarily SSRIs • in general, neither depression nor SSRIs cause birth defects • there is some evidence that newborns act somewhat depressed (lower activity level, more sleeping, longer latency to respond to stimulation) but these effects generally decline over the next month after birth

43. Individual DifferencesTeratogens Maternal anxiety and stress • fetuses: higher activity level • infants: cried & fussed more and had difficulties with emotion regulation & social behavior • children: more likely to show symptoms of ADHD and anxiety, lower attention ability, & socioemotional problems • adolescents: continue to show problems with ADHD and anxiety & have lower IQ scores compared to children of non-anxious mothers • adults: more susceptible to mental illness, including schizophrenia, depression, and anxiety

44. Individual DifferencesTeratogens Maternal anxiety and stress • elevated cortisol levels in mothers likely affect the development of the fetal brain & HPA axis, making it more susceptible even to mild stresses later in life • effective interventions include behavioral stress reduction (e.g., meditation, hypnosis) and… eating chocolate!

45. Individual DifferencesTeratogens AIDS • proportion of infants who contract AIDS prenatally ranges from 15 (Europe and North America) to 30% (Africa) • may contribute to low birthweight, but difficult to separate its effects from the effects of other risk factors • biggest risk comes after birth, when infants begin to show signs of the disease

46. Individual DifferencesTeratogens Other toxins • modern environment is made up of many potentially harmful chemicals, pollutants, and radiation • exposure to environmental toxins during pregnancy has the potential to influence not only the fetus but possibly the fetus’ children and grandchildren!

47. Can Birth Defects Be Prevented? • Many birth defects can be diagnosed prenatally through genetic counseling & techniques like amniocentesis • Treatments include fetal medicine, postnatal intensive care, and abortion • abortion is controversial, especially if it is done because of low income or for family planning

48. Family and SocietyMothers • Pregnancy brings many changes • transition to parenthood is a big shift • many pregnant U.S. mothers worry about appearance • Mother & fetus are a unique biological system – each changes in response to the other • good nutrition is essential

49. Family and SocietyMothers Successful adaptation to pregnancy is related to • knowledge of pregnancy & childbirth • the presence of the father • marital satisfaction • low levels of family stress • social support from family and friends • ability to remain active • emotional well-being

50. Family and SocietyFathers • Fathers often identify with their partners’ changes & act in supportive roles • Some have difficulties adapting to the pregnancy • may feel emotionally distant, engage in extramarital sex, or even abuse (about 1 in 6 women in the U.S.) • risk for abuse increases with factors such as teenage pregnancy, low social support, low income, unmarried status, unplanned pregnancy, drug & alcohol abuse, and poor prenatal care