Chapter 13 Labor and Birth Processes All Elsevier

Factors Affecting Labor At least five factors affect process of labor and birth. Five P’s: Passenger (fetus and placenta) Ø Passageway (birth canal) Ø Powers (contractions) Ø Position of mother Ø Psychologic response Ø All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 2

Factors Affecting Labor (Cont. ) Passenger Size of fetal head Ø Fetal presentation Ø Fetal lie Ø Fetal attitude Ø Fetal position Ø All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 3

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Factors Affecting Labor (Cont. ) Passageway Ø Passageway, or birth canal, is composed of: • • • Bony pelvis Cervix Pelvic floor muscles Vagina Introitus (external opening to the vagina) All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 10

Factors Affecting Labor (Cont. ) Powers Ø Primary powers • Effacement • Dilation • Ferguson reflex Ø Secondary powers • Bearing-down efforts All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 15

Factors Affecting Labor (Cont. ) Position of laboring woman Position affects woman’s anatomic and physiologic adaptations to labor Ø Frequent changes in position Ø • Relieve fatigue • Increase comfort • Improve circulation Ø Laboring woman should be encouraged to find positions most comfortable to her All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 17

Process of Labor Labor: process of moving fetus, placenta, and membranes out of uterus and through birth canal Various changes take place in woman’s reproductive system in days and weeks before labor begins Labor can be discussed in terms of mechanisms involved in process and stages woman moves through All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 18

Process of Labor (Cont. ) Signs preceding labor Lightening or dropping Ø Bloody show Ø Onset of labor Ø Onset of true labor cannot be ascribed to single cause. Many factors involved, including changes in maternal uterus, cervix, and pituitary gland All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 19

Process of Labor (Cont. ) Stages of labor Ø First stage • Onset of contractions to full dilation of the cervix Ø Second stage • Full dilation to birth Ø Third stage • Birth of the fetus until delivery of the placenta Ø Fourth stage • 2 hours postdelivery of the placenta All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 20

Process of Labor (Cont. ) Mechanism of labor Ø Seven cardinal movements of mechanism of labor that occur in vertex presentation • • Engagement Descent Flexion Internal rotation Extension Restitution and external rotation Expulsion (birth) All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 21

Physiologic Adaptation to Labor Fetal adaptation Ø These changes occur in: • Fetal heart rate • Fetal circulation • Fetal respiration All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 24

Physiologic Adaptation to Labor (Cont. ) Maternal adaptation Ø As a woman progresses through stages of labor, various body system adaptations cause her to exhibit both objective and subjective symptoms All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 25

Physiologic Adaptation to Labor (Cont. ) Maternal adaptation Cardiovascular changes Ø Respiratory changes Ø Renal changes Ø Integumentary changes Ø Musculoskeletal changes Ø Neurologic changes Ø Gastrointestinal changes Ø Endocrine changes Ø All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 26

Question A pregnant woman is at 38 weeks of gestation. She wants to know if any signs indicate that “labor is getting closer to starting. ” The nurse informs the woman that this is a sign that labor may begin soon: Weight gain of 1. 5 to 2 kg (3 to 4 lbs) Increase in fundal height Urinary retention Surge of energy All Elsevier items and derived items © 2014, 2010, 2006, 2002, Mosby, Inc. , an imprint of Elsevier Inc. 27