Prenatal Development PDF

# Research Methods ## Research Methods - **Quantitative Research:** deals with objectively measurable, numerical data. It is based on the **scientific method**: - 1. Identification of a problem - 2. Formulation of hypotheses - 3. Collection of data - 5. Formation of tentative con...

# Research Methods ## Research Methods - **Quantitative Research:** deals with objectively measurable, numerical data. It is based on the **scientific method**: - 1. Identification of a problem - 2. Formulation of hypotheses - 3. Collection of data - 5. Formation of tentative conclusions - 6. Dissemination of findings - **Qualitative Research**: focuses on the how and why of behavior (great depth & detail; less rigorous, subject to bias; small sample, less replicable) ## Research Methods Sampling - **Sample** is the smaller group within the population. - **Should adequately represent the population under study** - **Done through random selection** - Selection of a sample in such a way that each person in a population has an equal and independent chance of being chosen. ## Research Methods - Methods of Collecting Data - **Self-Report**: (quickest; asked about some aspect of life through a diary, visual reports, interviews which can be structured or open-ended, or questionnaire) - **Advantage:** Firsthand information; avoid the need for verbal skills - **Disadvantage:** Distorted responses - **Naturalistic Observation** (Real-life settings) - **Advantage:** a good description of the behavior, avoid unnatural settings that distort behavior - **Disadvantage:** lack of control; observer bias - **Laboratory Observation** (Controlled setting) - **Advantage:** good description; greater control - **Disadvantage:** observer bias; artificial - **Behavioral and performance measures** (Participants are tested on abilities, skills, knowledge, competencies, or physical responses; an objective measure; should be valid, reliable, and standardized) - **Advantage:** objectively measurable information - **Disadvantage:** cannot measure nonbehavioral phenomena; can be affected by extraneous factors ## Research Methods - Basic Research Designs - **Case Study (in-depth study of a single individual)** - **Advantage:** detailed picture of behavior and development; generate hypothesis - **Disadvantage:** not generalizable; not testable; cause and effect - **Ethnographic Study**: a case study of culture - **Correlational Study**: correlation or statistical relationship between variables ## Research Methods - Basic Research Designs - Experiment - **Experiment**: (controlled procedure in which the experimenter manipulates variables to learn how one affects another) - **Experimental group:** consists of people who are to be exposed to the experimental manipulation or treatment - **Control group:** consists of people who are similar to the experimental group but do not receive the experimental treatment or may receive a different treatment. - **Double-blind Procedures**: in which neither participants nor experimenters know who is receiving the treatment and who is instead receiving an inert placebo - **Independent Variable**: the experimenter has direct control - **Dependent Variable**: may or may not change as a result of changes in the independent variable - **Operational definition**: the definition stated solely in terms of the operations used to measure a phenomenon ## Research Methods - Time Span of Research - **One goal of developmental research is to study change over time.** - **Cross-Sectional**: (individuals of different ages are assessed at one point in time) - **Advantage:** Can show similarities and differences among age groups; speedy, economical; presents no problem of attrition or repeated testing. - **Disadvantage:** Cannot establish age effects; masks individual differences; can be confounded by cohort effects. - **Longitudinal**: (researchers study the same person or group of people over time, sometimes years apart) - **Advantage:** Can show age-related change or continuity; avoids confounding age with cohort effects. - **Disadvantage:** Is time-consuming, expensive; presents problems of attrition, bias in sample, and effects of repeated testing, results may be valid only for cohort tested or sample studied - **Sequential**: (track people of different ages like cross-sectional designs, over time like longitudinal designs) - **Requires large amount of time and effort and analysis of very complex data** # Conducting Ethical Research ## Conducting Ethical Research - Information Consent - **Informed Consent**: All participants must know what their research participation will involve and what risks might develop. ## Conducting Ethical Research - Confidentiality - **Confidentiality**: Researchers are responsible for keeping all of the data they gather on individuals completely confidential and, when possible, completely anonymous. ## Conducting Ethical Research - Debriefing - **Debriefing**: After the study has been completed, participants should be informed of its purpose and the methods that were used. ## Conducting Ethical Research - Deception - **Deception**: The psychologist must ensure that the deception will not harm the participants and that the participants will be debriefed as soon as possible after the study is completed. - **Three Principles in Resolving Ethical Dilemmas** - 1. **Beneficence**: the obligation to maximize potential benefits to participants and to minimize potential harm. - 2. **Respect**: participants should be autonomous about participating and those who has diminished autonomy should be protected. - 3. **Justice**: the inclusion of diverse groups together with sensitivity to any special impact the research may have on them. # Prenatal Development ## Prenatal Development & Gestation - **Prenatal development occurs in three stages of gestation.** - **Gestation**: is a period between conception and birth - **Gestational age**: is the age of an unborn baby, usually dated from the first day of an expectant mother's last menstrual cycle. ## Prenatal Development Principles - **Development proceeds according to two fundamental principles:** - **Cephalocaudal principle** - **Proximodistal principle** # Stages of Prenatal Development - The Germinal Stage ## Prenatal Development - Germinal Stage - **Fertilization to two weeks** - **It includes the creation of the fertilized egg, called a zygote; cell division; and the attachment of the zygote to the uterine wall.** - 1. **Fertilization** or conception takes place to create a single cell called a zygote. - 2. The zygote then duplicates itself again and again by cell division (mitosis). - 3. While the fertilized ovum is dividing, it travels down through the fallopian tube to the uterus or womb (3-4 days). - 4. The **Blastocyst** implants itself into the wall of the uterus. But before implantation, an embryonic disk is formed, and three layers of cells form from it- ectoderm, mesoderm, and endoderm. # Stages of Prenatal Development - The Embryonic Stage ## Prenatal Development - Embryonic Stage - **Begins after the implantation (2 to 8 weeks)** - **During this period, the rate of cell differentiation intensifies, support systems for cells form, and organs appear.** - **In cell differentiation, the mass of cells is now called an embryo.** - **Ectoderm**: (nervous system and brain, sensory receptors, and skin parts) - **Mesoderm**: (circulatory system, bones, muscles, excretory system, and reproductive system) - **Endoderm**: (digestive and respiratory systems) - **As the embryo's three layers form, life-support systems for the embryo develop rapidly.** - The **Amniotic cavity/ amniotic sac/ amnion** is a fluid-filled membrane that encases the developing embryo, protecting it and giving it room to move and grow. - The **Umbilical cord** contains two arteries and one vein, and connects the baby to the placenta. - The **Placenta** allows oxygen, nourishment, and wastes to pass between the mother and embryo. - **The organs and major body systems develop rapidly in a process known as Organogenesis.** - **Critical period**: the embryo is most vulnerable to destructive influences in the prenatal environment. - **Severely defective embryos usually are spontaneously aborted during the first trimester of pregnancy.** - **Spontaneous abortion or miscarriage**: is the expulsion from the uterus of an embryo or fetus that is unable to survive outside the womb. - **Stillborn**: is a miscarriage that occurs after 20 weeks of gestation. # Stages of Prenatal Development - The Fetal Stage ## Prenatal Development - Fetal Stage - **The appearance of the first bone cells marks the beginning of this stage.** - **During this period, the fetus grows rapidly, and "finishing touches" continue to develop.** - **Sex**: is detectable three months after conception. - **Quickening**: a mother can feel the fetus move in the fourth month. - **Fetal lie**: At the fifth month, the fetus is more active, showing a preference for a particular position in the womb. Likewise, a lanugo covers the body of the fetus - **Viable**: At the sixth month, the fetus has a chance of surviving outside the womb. - **Reflex patterns**: During the seventh month, the fetus has fully developed reflex patterns. # Hazards to Prenatal Development ## Hazards to Prenatal Development - Teratogens - **The developing organism can be greatly affected by its prenatal environment - the mother's body.** - **Teratogen**: is an environmental agent, such as a virus, a drug, or radiation, that can interfere with normal prenatal development. - **The severity of the damage to an embryo or fetus and the type of defect depends on the dose, genetic susceptibility, and time of exposure.** - **Prescription and nonprescription drugs can function as teratogens.** - **Psychoactive drugs**: such as caffeine, alcohol, nicotine, cocaine, marijuana, and heroine - **Alcohol**: leads to Fetal alcohol spectrum disorders (FASD). - **Nicotine**: leads to Sudden infant death syndrome (SIDS, also known as crib death) - **Incompatible blood types between the mother and father pose another risk to prenatal development.** - **Environmental hazards**: such as radiation, toxic wastes, and other chemical pollutants. - **Maternal diseases and infections**: can produce defects in offspring by crossing the placental barrier, or they can cause damage during birth. # Prenatal Care ## Prenatal Care - Testing and Early Care - **Ultrasound, amniocentesis, chorionic villus sampling, embryoscopy, preimplantation genetic diagnosis, umbilical cord sampling, and maternal blood tests can be used to determine whether an unborn baby is developing normally.** - **Early, high-quality prenatal care is essential for healthy development.** It can lead to detection of defects and disorders and, especially if begun early and targeted to the needs of at-risk women, may help reduce maternal and infant death, low birthweight, and other birth complications # The Birth Process ## The Birth Process - Stages of Labor - **Birth normally occurs after a preparatory period of parturition.** - **Parturition**: is the act or process of giving birth. - **Typically begins 2 weeks before delivery.** - **A woman may have felt false contractions known as Braxton-Hicks contractions, at times during the final months ofpregnancy, or even as early as the second trimester,when the muscles of the uterus tighten for up to 2 minutes.** - **Real labor contractions are more frequent, rhythmic, and painful, and they increase in frequency and intensity.** ## Stages of Childbirth - **Stage 1**: **DILATION** of the cervix - Longest, lasting for about 12 to 14 hours. - Uterine contractions are 15 to 20 minutes apart at the beginning. - Toward the end of the first stage, contractions occur every 2 to 5 minutes. - This stage lasts until the cervix is fully open (10 centimeters, or about 4 inches). - **Stage 2**: **DESCENT** and emergence of the baby - Begins when the baby's head starts to move through the cervix and the birth canal. - Typically lasts up to an hour. - Terminates when the baby completely emerges from the mother's body. - **Stage 3**: **EXPULSION** of the placenta/ Afterbirth - The placenta and the remainder of the umbilical cord are expelled from the mother. # The Newborn Baby ## The Neonatal Period - Size and Appearance - **The neonatal period, the first 4 weeks of life, is a time of transition from the uterus to an independent existence.** - **During the first few days, the neonate loses weight and then regains it.** - **They have distinctive features including a large head, a receding chin, and an area on their heads known as fontanels.** - **Some neonates are very hairy because of the lanugo during prenatal and almost all new babies are covered with vernix caseosa (cheesy varnish).** ## The Neonatal Period - Body Systems and State of Arousal - **After birth, all of the baby's systems and functions must operate on their own.** - **During the first few days infants secrete meconium, a stringy, greenish-black waste matter formed in the fetal intestinal tract.** - **Three or four days after birth, about half of all babies develop neonatal jaundice caused by the immaturity of the liver.** - **A newborn's state of arousal is governed by periodic cycles of wakefulness, sleep, and activity, which seem to be inborn and sleep takes up the major, but a diminishing, amount of a neonate's time.** - **Newborns' activity levels show stability and may be early indicators of temperament.** # Complications of Childbirth ## Complications of Childbirth - Low Birth Weight - **Low birth weight is a major factor in infant mortality and can cause long-term physical and cognitive problems.** - **1. Low-birth-weight babies (LBW)**: neonates born weighing less than 2,500 grams (5 pounds) at birth. - **Preterm (premature) infants**: are babies born before the 37th week of gestation, making them smaller than a full-term infant. - **Small-for-date (small-for-gestational-age) infants**: are babies born at or around their due dates but are smaller than would be expected (poor nutrition) - **Very-low-birthweight babies have a less promising prognosis than those who weigh more.** - **Risk factors or factors increasing the likelihood that a woman will have an underweight baby include:** - **1. Demographic and socioeconomic factors**: (age, poor, unmarried, uneducated) - **2. Medical factors predating the pregnancy**: (more than four children, short or thin, previously low birth; uti, hypertension) - **3. Prenatal behavioral and environmental factors**: (nutrition, prenatal care, drugs, stress) - **4. Medical conditions associated with the pregnancy** - **Two increasingly used interventions in the neonatal intensive care unit (NICU) are:** - **1. Kangaroo Care**: which is an intervention involving extended skin-to-skin contact - **2. Gentle massage**: may foster growth, weight gain, motor activity, alertness, and behavioral organization ## Complications of Childbirth - Postmaturity and Stillbirth - **2. Postmature**: is fetus not yet born as of 2 weeks after the due date or 42 weeks after the mother's last menstrual period. They tend to be long and thin. - **Babies who stayed too long in the womb are at greater risk of shoulder dystocia, meconium aspiration, low Apgar scores, brain damage, and death.** - **The baby's greater size also complicates labor and puts the mother at higher risk of cesarean delivery, perineal tears, and postpartum hemorrhage** - **3. Stillbirth**: - **The sudden death of a fetus at or after the 20th week of gestation.** - **Can be diagnosed prenatally or can only be discovered during labor or delivery.**