Chapter 4 Prenatal and Birth
Chapter 4Prenatal and Birth
Early Timetable of Prenatal Development, Adapted from Figure 4.1, page 90Sun Mon Tues Wed Thurs Fri Sat
1Last menstrual period
2 3 4
5 6 7 8 9 10 11
12 13 14Ovulation
15Fertilization
16 17 18
19 20Zygote attaches to wall
21ImplantationBegins
22 23 24Ends
25
26 27 28Placenta, umbilical cord dev.
29First menstrual period missed
30
Signs of Pregnancy Nausea Fatigue Breast Tenderness Missed Period
Prenatal Development Begins at conception
Ends at birth
Proceeds through three stages: Germinal stage Embryonic stage Fetal stage
Prenatal DevelopmentGerminal Stage
Conception until the fertilized egg implants into the uterine wall
About 2 weeks
• Zygote• Cell Divides
Fertilization of egg
• Attaches to wall
• 1mm in diameter
Zygote travels
to Uterus
• Triggers 1st signs
• Umbilical cord• Placenta
Hormonal Change
http://www.whattoexpect.com/pregnancy/week-by-week/weeks-1-and-2.aspx#
http://www.babyzone.com/pregnancy-week-by-week/
Germinal Stage Complications Ectopic Pregnancies
Outside of the uterus 1 out of 100 pregnancies
Multiples 1 out of 80 pregnancies Twin pregnancy 4x greater than twin
births (often 1 embryo spontaneously aborts early in development
3 or more babies 4x greater since 1980s
Prenatal Development Embryonic Stage
Implantation until about eight weeks Usually 2-8 weeks
Major organs and body parts develop daily; environmental damage most likely to occur
Three layers of cells (around 3rd week): 1) Ectoderm - Skin cells, Nervous system2) Mesoderm - Muscles, bones, circulatory system3) Endoderm - Digestive System and lungs
http://ultrasound-images.com/fetal-heart.htm
Embryonic Stage Cephalocaudal Development
Growth occurs from the head downwards
Proximodistal Development Growth occurs from the central axis
(center of the body) outwards
95% of the major body structures are developed
and some are functioning
Prenatal Development Fetal Stage
Weeks 9-birth Existing organs and structures become defined Brain develops rapidly 16th week Quickening – fetal movements Rate growth during the fetal stage is greater
than at any other time 7th month survival is possible with NICU
1st Trimeste
r
2nd Trimeste
r
3rd Trimeste
r
Germinal Embryotic Fetal
Conditions Influencing Pregnancy and Prenatal Development 80% of birth defects caused by
environmental problems during prenatal development
Two lines of protection from environmental influences: Amniotic fluid – protects the fetus from
physical injuries Placental barrier – created by blood vessel
walls that separate the maternal and fetal circulatory system
Teratogens / Environment Teratogen – agents that cross the placental
barrier and cause or increase the incidence of physical, behavioral, and/or cognitive deficits in children
Severity depends upon: When exposed Amount of exposure Fetal characteristics
Teratogen Effects
There is a similar table in your textbook on page 97
Some Possible Teratogens Disease – rubella, syphilis, pediatric
aids, etc.
Drugs – alcohol, cigarettes, cocaine, heroin, etc.
Environmental – lead, pesticides, radiation, chemicals, etc.
Other Conditions Affecting Pregnancy Maternal Age
35 yrs old + - risks increase Down syndrome High blood pressure Gestational diabetes Miscarriage Twins
Other Conditions Affecting Pregnancy Maternal Stress
Stress produces hormones that cross placental barrier and effect fetus
Extreme and prolonged stress increases the risk for: Miscarriage difficult labor and delivery prematurity
Other Conditions Affecting Pregnancy Parity:
Number of children Spacing between children
A woman’s endocrine system takes four years to return to pre-pregnancy condition
A pregnancy within 3 months of delivery is classified as high-risk
Protective Factors Nutrition
Good food + weight gain = healthy baby Iron, protein, folic acid, water
Exercise Provides more energy, builds bones and
muscles, improves health, and increases ability to cope with childbirth pain
Protective Factors
Prenatal Care Lower rates of birth complications
Social Support Minimizes effects of stress and helps in
dealing with physical demands or complications that arise during pregnancy
How is a Baby Born? The Birth Process
280 Days = Due date Only 3% of babies born on due date 45% within one week (before or after)
What Triggers Labor? Mother’s body releases
Prostaglandis (fatty acids) Oxytocin (hormone) Change in uterus molecules
Lightening Baby drops into the pelvic cavity;
pressure is decreased on the mother’s diaphragm
Mother can breathe easier
The Birth Process Braxton-Hicks Contractions
Throughout pregnancy and especially during the last month or two
Mild irregular contractions of the uterus
False Labor During late pregnancy Moderately intense and rhythmic
contractions
The Birth Process Stage 1: Dilation of the Cervix
True Contractions 30-60 seconds; 5-20 minutes apart
Cervix working towards opening to 10cm; mucous plug is dislodged
Amniotic sac may tear – aka “water breaks”
Transition phase – last part of dilation Epidural block (blocks pain from the waist to the feet)
may be given so cervix can continue to dilate fully before mother begins pushing
Heart rate of baby monitored
The Birth Process Stage 2: Birth of the baby
Cervix is fully dilated
Contractions help push baby out 60 seconds; 1-3 minutes apart
Crowning When the top of the baby’s head becomes visible
Molding baby’s bones in skull, which are not yet fused,
press together and may even overlap to help baby pass through the birth canal
The Birth Process Stage 2: Birth of the baby
Episiotomy A small incision in the skin below the vagina may
be needed to create a larger opening for the baby’s head
Delivery As short as 5 minutes 1-2 hours for first time moms Baby turns so the shoulders can fit through
vaginal opening After shoulders are delivered the rest of the baby
slides out
The Birth Process Stage 3: Expulsion of the Placenta
15 – 30 minutes after delivery Contractions continue, helping the placenta
move through the birth canal No longer needed
https://www.youtube.com/watch?v=mOP52g_rO24
Birthing Methods 19th century – Midwives
1950s – at hospital
Today – 99% delivered at hospital
Options for families Birthing centers Bathtub Midwives Family/coach in room
Birthing Methods Lamaze Childbirth
Six weekly sessions, learn how to: Breathe during labor and delivery to control
pain and discomfort Focus on relaxing thoughts and feelings Have fathers or other partners help in labor
and delivery
Birthing Methods Leboyer Method
Minimize infant’s trauma Mimics the conditions of the mother’s womb Dim lighting Delivery room temperature closer to
mother’s body temperature After delivery and before the umbilical cord
is cut, the naked infant is placed on mother’s bare belly
The infant is given a warm bath
Complications Cesarean Sections
A non-vaginal birth where the fetus is delivered through an incision in the mother’s abdomen
Delay in delivery, compromise health of infant United States - 900,000 per year
Table 4.1, page 1121. Unfavorable shape of
pelvis2. Breech presentation3. Placenta previa4. Cord prolapse5. Fetal distress6. Eclampsia7. Prolonged labor8. Diabetes
Complications Breech presentation
Baby is bottom or feet first
Transverse presentation Shoulders or arms leading
Induced Labor Pitocin or other medication About 20% of women 1999
Mother’s Perspective “Baby” Blues” - 70-80% of new mothers
experience - contributing factors: Biological changes Fatigue Loss of attention Increased demands at home Sense of anticlimax Feelings of inadequacy
Postpartum depression Intense feelings of sadness, anxiety or despair
that disrupt the mother’s ability to function and interact with her child
Fatherhood Readiness
Mature Regress
Jealous
Loss of attention
Loss of freedom
Closeness to spouse
Aware of Personal
relationships
Actively participate
Newborns – also known as Neonate Stress hormones released during
delivery
Causes newborn to be alert Helps lungs Can withstand stress Increases metabolism Increases energy supply May promote development of emotional ties
between parents during first hours of life Not present for cesarean delivered newborns
Characteristics of Newborn/Neonate
Newborn/Neonate Infants who are adapting to life outside
the womb, usually first month or two
Four big goals of the newborn/neonate: Breathe on their own Blood circulation Control body temperature Ingesting food
Four Big Goals of Newborn…. Breathe on their own
Newborn must switch from oxygen provided by the umbilical cord blood to breathing on his own
Blood circulation When the link to the placenta is severed,
circulation changes so that blood flows to the lungs for the first time.
Four Big Goals of Newborn…. Control body temperature
The environment outside the womb is susceptible to extreme changes in temperature
Ingesting food In utero, nutrients are provided through the
placenta. After birth, the newborn must learn how to obtain nourishment through the mouth
Characteristics of Newborn/Neonate Avg. Length 19-21 inches Avg. weight 7 – 7.5 pounds Vaginal Delivery
Misshaped head Swollen face Flat nose
White waxy covering – vernix caseosa – provides protection against bacteria
Uneven coloring Bluish/grayish fingers, nose, feet
Assessing the Newborn/Neonate Apgar Scale (page 119) means:
Appearance (skin color) Pulse (heart rate) Grimace (reflex irritability) Activity (muscle ton) Respiration
Newborn assessed using the APGAR scale approximately 1 to 5 minutes after delivery Score
8 to 10 – big cry, adjust on their own 4 to 7 – need help, closely observed 0 to 3 – limp, unresponsive, NICU
Behavior of Newborn/Neonate Neonatal Behavioral Assessment
Scale Developed by T. Berry Brazelton
Measure newborn’s responses to the environment: Reflexes Motor Capabilities Control attention Behavior Response to interactions with others
Some Terms: Preterm (premature)
Born prior to 37 weeks
Low birthweight Born after 37 weeks, less than 5
pounds Lower the weights = more problems
IntelligenceMotor performanceAttention Behavior
Neonatal Intensive Care Unit (NICU) Most preterm newborns with developmental
problems are placed in NICU First step – warmth All vitals monitored 2 to 9% newborns Limited interaction with family Encourage skin to skin contact