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