The 4 P's Of Labor and Delivery

Labor

• Labor involves uterine contractions and abdominal pressure.
• It culminates in expelling the fetus and placenta.

Common Components of Labor (4 Ps)

• These include the passage, passenger, powers, and psyche.

The Passage (Woman's Pelvis)

• Refers to the route the fetus takes, including the cervix and vagina.

Pelvic Measurements

• Diagonal Conjugate should measure 11.5cm or greater.
• Transverse Diameter should measure 13.5.

The Passenger (The Fetus)

• The fetus should be of appropriate size and in an advantageous position and presentation.
• The fetal head is the body part with the widest diameter.

Molding

• Shaping of the fetal skull due to uterine contractions.
• It involves pressing the vertex against the undilated cervix.

Types of Fetal Presentation

• Cephalic: Head is presenting (vertex).
• Breech: Buttocks or feet are presenting.
• Shoulder: Transverse lie, fetus positioned horizontally in the pelvis.

The Powers of Labor

• Adequate uterine contractions are necessary.

Phases of Uterine Contractions

• Increment: Intensity increases.
• Acme: Strongest phase.
• Decrement: Intensity decreases.

The Psyche or a Woman's Psychological State

• This can either encourage or inhibit labor.
• It is influenced by past and present psychological experiences.

True Labor Signs

• Regular contraction timing.
• Radiating contraction pain.
• Contraction pain is unrelieved by activity.
• Exam changes are present.
• Heavy bleeding is present.
• Fetal movement decreases.
• Contractions occur every 5 minutes or longer, lasting more than 2 hours

False Labor (Braxton Hicks)

• Does not cause changes to the cervix or baby's position
• Activity diminishes contractions
• Contractions are felt above the belly button and do not radiate
• Erratic timing: inconsistent, but may improve with hydration

Mechanism of Labor (Cardinal Movements)

• Engagement: Fetal head's largest diameter fits into the maternal pelvis's largest diameter
• Descent: Downward movement occurs weeks before labor in nulliparas and with engagement in multiparas
• Flexion: Fetal head touches the pelvic floor.
• Internal Rotation: Occiput rotates.
• Extension: The head extends.
• External Rotation: Head rotates to the diagonal or transverse position.
• Expulsion: The body follows smoothly after the shoulder.

Cervical Changes

• Effacement: Shortening/thinning of the cervical canal to 1-2cm long
• Dilatation: Enlargement and widening to approximately 10cm.

Stages of Labor

• First Stage (Dilatation): Initiation of true labor contractions until full cervical dilation is achieved.
• Second Stage: Full dilatation until the infant is born.
• Third Stage: Placental stage.

Fourth Stage

• This is the first 1-4 hours after the placenta is delivered
• Close maternal observation required

Duration of Labor

• Lasts approximately 12 hours, divided into latent, active, and transition phases.

Latent Phase

• Early phase where uterine contractions end with rapid cervical dilation.
• Cervix dilates to 1-4 cm and thins.
• Mild and strong contractions lasting 5-30 minutes, every 30-40 seconds

Active Phase

• Cervical dilation of 4-7 cm with further thinning.
• Stronger contractions lasting every 40-60 seconds, every 3-5 minutes.
• May include rupture of membranes.
• Typically lasts 4-8 hours.

Transition Phase

• Cervix dilates from 8-10 cm and thins.
• The shortest but most intense and painful phase.
• Lasts 30 minutes to 2 hours.
• Contractions peak every 2-3 minutes and last 60-90 seconds.

Nursing Management During Labor Stages

• Encourage controlled breathing, walking, and preparation for hospital stay.
• Older children will need to be prepared for going home
• Offer pain relief through aromatherapy and non-pharmacologic methods.
• Support and breathing techniques.
• Encouragement.
• Monitor mother's vitals and fetal heart rate
• Assess fetal position
• Identify uncontrollable urges to push
• Monitor BP and fetal HR before, during, and after contractions.
• Continuous fetal monitoring.

Crowning

• Fetal head is visible at the vaginal opening.

Third (Placental) Stage

• Occurs after the birth of infant
• Palpate the uterus
• Ensure it is firm, round, and located just below the umbilicus

Delivery Mechanism of the Placenta

• Schultz Mechanism: Shiny side from the baby side.
• Duncan Mechanism: "Dull/Dirty" side is red and rough with maternal side visible

Postpartum Nursing Management

• Monitor BP before and after placental delivery.
• Administer oxytocin ("Pitocin")
• As prescribed
• after delivery of the placenta.
• Promote comfort and bonding, change linens, and provide peri-care

Fourth Stage (Recovery)

• Monitor mother's health status due to risks of hemorrhage, infection, and uterine atony.
• Monitor vital signs
• Monitor lochia (vaginal discharge)
• Monitor uterine firmness

Fundus

• Decreases 1cm each day
• Administer pain relief and apply witch hazel with ice for perineal edema
• Encourage bonding and breastfeeding

Maternal Danger Signs in Labor

• High or low blood pressure
• Systolic > 140 mmHg or diastolic > 90 mmHg are criteria for gestational hypertension.
• Falling BP could be a sign of intrauterine hemorrhage.
• Watch for apprehension, increased pulse rate, and pallor related to hypovolemic shock
• Abnormal Pulse: >100 bpm may indicate hemorrhage.
• Inadequate or prolonged contractions.
• Abnormal abdominal contour can be a sign of a full bladder
• Increasing apprehension

Fetal Danger Signs in Labor

• Meconium staining: Green amniotic fluid indicates fetal distress.
• High or low fetal heart rate.
• Hyperactivity indicates hypoxia.
• Low O2 saturation.

Fetal Monitoring

• Normal fetal O2 is 46-52% (1st period) to 44-50% (2nd period) with normal HR of 110-160bpm
• Accelerations: Normal increases in FHR due to movement.
• Early Decelerations: Normal decreases in FHR with contractions, from fetal head compression.
• Late Decelerations: Indicate decreased blood flow to the uterus.
  • Causes: Uteroplacental insufficiency, amniotic fluid infection, or low maternal blood pressure.
• Variable Decelerations: Indicate compression, occurring at unpredictable times.

Fetal Growth and Development

• Begins with fertilization.
• Divided into pre-embryonic, embryonic, and fetal stages.

Fertilization

• Sperm viable for 48-72 hrs, fertile for 24 hrs
• Ova fertile for 12 to 24hrs after ovulation
• Coitus must occur +/- 24hrs for fertilisation
• Union of ovum and sperm results in a zygote
• Occurs in the fallopian section

Pre-Embryonic Stage

• Lasts 14 days from contraception
• Zygote implants, and the structure becomes an embryo (8-10 days)
• Rapid growth and tissue differentiation (ectoderm, mesoderm, and endoderm)

Germ Layers of the Embryo

• Ectoderm: Develops into the CNS, PNS, sensory epithelium, skin, hair, nails, and glands
• Mesoderm: Develops into bone, cartilage, connective tissue, muscle, cardiovascular system, blood, and kidneys
• Endoderm: Develops into respiratory and GI tract epithelium, bladder, urethra, liver, and pancreas

Embryonic Stage

• Begins the 3rd week after conception
• Continues until crown-to-rump length of 3 cm (1.2 inches) by the 8th week
• Now known as a fetus

Fetal Stage

• Begins 8-10 weeks conception and continues during pregnancy
• Fetus is fully developed structurally
• Receives O2 and excretes through the placenta. Fetal lungs are fluid-filled
• 3 shunts (ductus arteriosus, venosus, and foramen ovale) must shut at birth for blood flow

Wk 12

• Genitalia developed enough to determine gender (ultrasonography)

Female Fetus

• Follicles and small amounts of estrogen in ovaries

Male Fetus

• Gonads form critical genetial tract in testes

Embryonic Support System:

• Corpus Luteum: Estrogen and progesterone for 2 months
• Decidua: Endometrium that becomes deciduous (lining of inside of uterus), implacts under the blastocyst
• Placenta: Transmits nutrients and O2
• Estrogen: Stimulates synthesis of receptors for progesterone.

Additional Properties of Each:

• Progesteron: Promotes viscosity of mucus protects against bacteria
• Promotes breast tissue growth
• Maintains uterine lining/implantation
• Relaxates uterine smooth muscle.

HCG

HCG

• Secreted by trophoblast cells (blastocyst and Placenta)
• Helps maintain the corpus luteum
• HCG can be detected in both urine and plasma (8 days)

Dizygotic

• Two or more fertilized, not identical

Monozygotic

• Identical, one fertilized ovum

Fetal Development Factors

• Environment, anatomical problems, maternal/fetal, and physiological problems.

Wk 4

• The embryo is 4 to 5 mm
• foundations for key body systems, and limbs (bud of legs and arms)

Genetic Principles

• Chromosomal/genes

Autosomal Disorders

• Autosomal Recessive- cystic fibrosis, Clinical Exp is homozygous.
• Autosomal Dominant- achondroplastic dwarfism, Clincal Exp is heterozygous

X-Linked Disorders

• X-Linked Dominant- appear almost every generation
• X-Linked Recessive- symptoms are expressed if homozygous

Pregnancy Screening

• History of carrier or effects
• Ethnic background can determine heritable disorders
• Check advanced maternal age with history
• Check for multiple anamolies
• Conduct a visual/display check on chromosome pattern-Karyotype

Fetal Tests

• MSAFP: Low MSAFP can signify down syndrome
• Triple screening: estriol

Amniocentesis

• fluid test of amniotic fluid

Vein Testing

• checks diseases, particularly if its in the blood

The goal of screening is to prevent tragic

genetic diseases and offer various reproductive options to at- risk couples Accurate screening hinges on the education and advocacy of physicians and nurses caring for people of reproductive age.

Vein Tests

• Checks if Rh+ factor in both blood types

The goal of screening is to prevent tragic

genetic diseases and offer various reproductive options to at- risk couples Accurate screening hinges on the education and advocacy of physicians and nurses caring for people of reproductive age.

Genetic Assessment Factors:

• OBGYN -History of infertility, incompetent cervic -Low birth rates, DES exposure
• Medical History -Infection or surgical problems
• Lifestyle -Alcohol intakes/lifestyle