Chapter 13

Labor and Birth Processes

Concept: Reproduction

Objectives

  • Define terms discussing the birth process: Understanding the specific vocabulary associated with the childbirth process.

  • Discuss the 5 Ps of labor and birth: Comprehensively detail the five critical factors influencing labor and delivery.

  • Identify malpresentation and its implications on birth: Understanding the different fetal presentations and their potential effects on the birthing process.

  • Define and discuss Stages of Labor: Explain the sequential phases of labor and their significance in childbirth.

Factors Affecting Labor

Labor and birth are influenced by five primary factors, commonly referred to as the Five P's:

  1. Passenger: Refers to the fetus and placenta.

  2. Passageway: The birth canal, comprising various anatomical structures.

  3. Powers: The contractions that facilitate labor.

  4. Position of the mother: The mother's body position during labor.

  5. Psychologic response: The psychological state of the mother during labor, which can affect her experience.

Detailed Aspects of the Five P's

Passenger

  • Size of fetal head: Influences the ease of passage through the birth canal.

  • Fetal presentation: The part of the fetus that is entering the birth canal first.

  • Fetal lie: The orientation of the fetus's body within the uterus, which can be vertical (longitudinal) or horizontal.

  • Fetal attitude: The degree of flexion of the fetus's limbs and neck. Ideally, the fetus should be in a state of general flexion, which facilitates birth. Common attitudes include:

    • Flexed

    • Extended

    • Without tone

  • Fetal position: The specific orientation of the fetus in relation to the mother's pelvis, including terms such as:

    • OA: Occipito-anterior (head down, facing mother's back)

    • OP: Occipito-posterior (head down, facing mother's abdomen)

    • Brow (sinciput) presentation

    • Mentum (chin)

Presentation Types and Dimensions

  • Frank breech:

    • Lie: Longitudinal or vertical

    • Presentation: Incomplete breech (sacrum presenting)

    • Attitude: Flexion, except legs at knees

  • Single footling breech:

    • Lie: Longitudinal or vertical

    • Presentation: Incomplete breech (sacrum presenting)

    • Attitude: Flexion, except one leg extended at hip and knee

  • Complete breech:

    • Lie: Longitudinal or vertical

    • Presentation: Breech (sacrum and feet presenting)

    • Attitude: General flexion

  • Shoulder presentation:

    • Lie: Transverse or horizontal

    • Presentation: Shoulder

    • Attitude: Flexion

Passageway

The birth canal consists of:

  • Bony pelvis: The pelvic bones that form the structure of the birth canal.

  • Cervix: The lower part of the uterus, which dilates during labor.

  • Pelvic floor muscles: Muscles that support the pelvic structures.

  • Vagina: Birth canal through which the fetus passes.

  • Introitus: The external opening to the vagina.

Powers

  • Primary powers:

    • Effacement: The thinning and shortening of the cervix during labor.

    • Dilation: The opening of the cervix, typically reaching a maximum of 10 centimeters (complete dilation).

    • Ferguson reflex: A natural urge to push during the second stage of labor.

  • Secondary powers:

    • Bearing-down efforts: Maternal pushing efforts during the second stage of labor.

Position of Laboring Woman

  • The mother's position during labor affects anatomical and physiological changes, including:

    • Relieving fatigue

    • Increasing comfort

    • Improving circulation

    • Potential impact on the descent of the fetus

  • Encouragement is provided to the laboring woman to find the most comfortable positions.

Psychologic Response

  • Assess factors that could affect labor:

    • Lack of support

    • History of sexual trauma

    • Being a teenager in labor

    • Previous negative birth experiences

    • Current life stressors

Process of Labor

Labor refers to the comprehensive process of moving the fetus, placenta, and membranes out of the uterus and through the birth canal. Several physiological changes occur within the maternal reproductive system in the days and weeks preceding labor, and labor can be understood in terms of mechanisms involved and stages.

Signs Preceding Labor

  • Lightening or dropping: Usually occurs weeks before labor in first-time mothers (primips), signaling the onset of labor.

  • Bloody show: The loss of the mucous plug or early cervical dilation, indicating that labor may commence soon.

  • Nesting: A surge of energy often noted in the days leading up to labor.

Onset of Labor

The commencement of true labor cannot be attributed to a singular cause; multiple factors contribute to the onset:

  • Changes in the maternal uterus, cervix, and pituitary gland.

Stages of Labor

The stages of labor are generally divided as follows:

  • First Stage: Lasts approximately 14-20 hours; begins with the onset of contractions and continues until the cervix is fully dilated to 10 centimeters (known as complete).

    • Subcategories:

      • Latent phase

      • Active phase

      • Transition phase

  • Second Stage: Typically lasts about 2 hours maximum; this is the stage from full dilation to the birth of the baby; practitioners often consider the need for a cesarean section if this stage extends beyond 2 hours.

  • Third Stage: This stage lasts approximately 5-30 minutes; it is from the birth of the fetus until the delivery of the placenta.

  • Fourth Stage: Involves monitoring for 2 hours post-delivery of the placenta.

Physiologic Adaptation to Labor

  • Fetal adaptation to labor is evaluated through:

    • Fetal heart rate

    • Fetal circulation

    • Fetal respiration

    • Assessing the fetus's well-being response to labor stress.

Question on Signs of Labor

A pregnant woman, nearing 38 weeks of gestation, inquires about signs that may indicate the imminence of labor. The nurse identifies that the following sign may suggest an impending labor:

  • Increase in fundal height

  • Surge of energy

  • Weight gain of 1.5 to 2 kg (3 to 4 lbs)

  • Urinary retention

Pregnancy Monitoring

  • Kick counts should begin in the third trimester when the mother can reliably perceive fetal movements:

    • Recommended frequency is 2-3 times a day, focusing on feeling for 10 fetal movements within 2 hours.

    • It is advised that mothers should have eaten recently, wait out fetal sleep cycles, and may lightly stimulate the belly or place a radio near the belly to encourage fetal movement.

    • The effect of obesity on fetal movement should be considered; insufficient movement noted after 12 hours warrants immediate medical assessment.

Amniocentesis

Indications:

  • Genetic testing typically performed around 16 weeks of gestation.

  • To determine fetal lung maturity in the third trimester via the L/S (lecithin/sphingomyelin) ratio.

  • Occasionally performed to relieve excess amniotic fluid in cases of polyhydramnios, a condition characterized by an excess of amniotic fluid.

Risks:

  • Oligohydramnios: Insufficient amniotic fluid, which poses risks to fetal health.

  • Maternal Risks:

    • Bleeding

    • Infection

    • Amniotic fluid embolism

    • Potential injury to surrounding organs (bowel, bladder)

    • Leaking amniotic fluid

  • Fetal Risks:

    • Fetal death

    • Injury from the needle

    • Infection

    • Bleeding

    • Premature birth

    • Spontaneous abortion within the first 20 weeks.

Rh Incompatibility

Rh incompatibility refers to the phenomenon that can occur when maternal and fetal blood mix during delivery or due to trauma, including procedures like amniocentesis or chorionic villus sampling. This can lead to maternal antibodies developing against fetal red blood cells, resulting in significant complications such as hemolysis. Key steps include:

  1. Establishing maternal blood type and Rh factor first.

  2. At birth, establish the newborn's blood type and Rh status using cord blood.

    • If the mother is Rh positive, there are no further concerns.

    • If the mother is Rh negative and the baby is Rh negative, again, there is no significant concern.

    • If the mother is Rh negative and the baby is Rh positive, Rhogam must be administered to prevent Rh sensitivity in subsequent pregnancies.

Administration of Rhogam

  • Dose procedures:

    • Administered via intramuscular injection.

    • Should also be given following any miscarriage or abortion if the mother is Rh negative since the blood type of the embryo is unknown.

    • For each subsequent pregnancy, the mother should receive Rhogam at 28 weeks and again after delivery if the infant is Rh positive.

Quiz Question on Rhogam Injection

Which patient would require a Rhogam injection?

  • A. An O+ woman who just delivered twins who are O+

  • B. An AB+ woman who just delivered a baby 48 hours ago who is A-

  • C. An A- woman who just delivered a baby who is also A-

  • D. An O- woman who just delivered a baby who is O+.