Mc graw hill oxorn foote human labor and birth 6th edition 2013 retail ebook ke

Posner, MDcM, Med, FRcSc Associate Professor, The University of Ottawa Department of Obstetrics and Gynecology The Ottawa Hospital Ottawa, Ontario, Canada Jessica Dy, MD, MPH, FRcSc Assi

HUMAN LABOR

& BIRTH Sixth Edition

broaden our knowledge, changes in treatment and drug therapy are required The authors and the publisher of this work have checked with sources believed to be re- liable in their efforts to provide information that is complete and generally in accord with the standards accepted at the time of publication However, in view of the pos- sibility of human error or changes in medical sciences, neither the authors nor the publisher nor any other party who has been involved in the preparation or publica- tion of this work warrants that the information contained herein is in every respect accurate or complete, and they disclaim all responsibility for any errors or omissions

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& BIRTH Sixth Edition

Glenn D Posner, MDcM, Med, FRcSc

Associate Professor, The University of Ottawa

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada

Jessica Dy, MD, MPH, FRcSc

Assistant Professor, The University of Ottawa

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada

amanDa Black, MD, MPH, FRcSc

Associate Professor, The University of Ottawa

Department of Obstetrics and Gynecology

The Ottawa Hospital

Division of Pediatric Gynecology, Children’s Hospital of Eastern Ontario Ottawa, Ontario, Canada

Griffith D Jones, MBBS, MRcoG, FRcSc

Assistant Professor, The University of Ottawa

Medical Director, Obstetrics & Gynecology Ultrasound

Division of Maternal–Fetal Medicine

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada

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DEDICA

Acknowledgments xvii

Part i: clinical Anatomy 1

1 Pelvis: Bones, Joints, and Ligaments 3

2 The Pelvic Floor 9

8 Engagement, Synclitism, Asynclitism 77

Part ii: First Stage of Labor 87

9 Examination of the Patient 89

10 Normal Mechanisms of Labor 101

11 Clinical Course of Normal Labor 119

12 Fetal Health Surveillance in Labor 143

13 Induction of Labor 173

14 Labor Dystocia 193

15 Abnormal Cephalic Presentations 211

Part iii: Second Stage of Labor 263

17 Operative Vaginal Delivery 283

Part iV: third Stage of Labor 351

19 Delivery of the Placenta, Retained

Placenta, and Placenta Accreta 353

Part Vi: other issues 567

32 Maternal Complications in Labor 601

33 Labor in the Presence of Fetal Complications 635

Yaa Amankwah, MBcHB, FRcSc

Assistant Professor, The University of Ottawa

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [18]

Nadya Ben Fadel, MD, FAAP, FRcPc

Assistant Professor, The University of Ottawa

Division of Neonatology

Department of Pediatrics

Children’s Hospital of Eastern Ontario

Ottawa, Ontario, Canada [39]

Dan Boucher, MD, MSc

Clinical Fellow, The University of Ottawa

Department of Medicine

The Ottawa Hospital

Ottawa, Ontario, Canada [32]

Yvonne cargill, MD, FRcSc

Assistant Professor, The University of Ottawa

Division of Maternal–Fetal Medicine

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [28]

Darine el-chaar, MD, FRcSc

Clinical Fellow, The University of Toronto

Division of Maternal–Fetal Medicine

Department of Obstetrics and Gynecology

The Toronto University Health Network

Toronto, Ontario, Canada [12, 15, 22, 23, 24, 25]

Ramadan el Sugy, MD, FRcSc

Department of Obstetrics and Gynecology

William Osler Health System

Brampton, Ontario, Canada [21] CONTRIBUTORS

Karen Fung Kee Fung, MD, FRcSc, MHPe

Associate Professor, The University of Ottawa

Division of Maternal–Fetal Medicine

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [29]

Laura M Gaudet, MD, MSc, FRcSc

Assistant Professor, Dalhousie University

Division of Maternal–Fetal Medicine

Department of Obstetrics & Gynecology

The Moncton Hospital, Horizon Health Network

Moncton, New Brunswick, Canada [33, 35]

catherine Gallant, MD, FRcPc

Assistant Professor, The University of Ottawa

Department of Anesthesiology

The Ottawa Hospital

Ottawa, Ontario, Canada [36]

Andrée Gruslin, MD, FRcSc

Professor, The University of Ottawa

Division of Maternal–Fetal Medicine

Departments of Obstetrics and Gynecology & Cellular and Molecular MedicineThe Ottawa Hospital

Ottawa, Ontario, Canada [34]

Samantha Halman, MD

Clinical Fellow, The University of Ottawa

Department of Medicine

The Ottawa Hospital

Ottawa, Ontario, Canada [32]

Alan Karovitch, MD, Med, FRcPc

Associate Professor, The University of Ottawa

Division of General Internal Medicine

Departments of Medicine & Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [32]

erin Keely, MD, FRcPc

Professor, The University of Ottawa

Division of Endocrinology and Metabolism

Departments of Medicine & Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [32]

Felipe Moretti, MD

Assistant Professor, The University of Ottawa

Division of Maternal–Fetal Medicine

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [38]

Lawrence oppenheimer, MD, MA, FRcSc, FRcoG

Professor, The University of Ottawa

Division of Maternal–Fetal Medicine

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [16, 19]

Dante Pascali, MD, FRcSc

Assistant Professor, The University of Ottawa

Division of Urogynecology and Pelvic Reconstructive Surgery

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [1, 2, 3, 4]

Samira Samiee, MD, FRcPc

Clinical Fellow, The University of Ottawa

Division of Neonatology

Department of Pediatrics

Children’s Hospital of Eastern Ontario

Ottawa, Ontario, Canada [39]

Gihad Shabib MD, MRcoG, FRcSc

Assistant Professor, The University of Ottawa

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [17]

George tawagi, MD, FRcSc

Assistant Professor, The University of Ottawa

Division of Maternal–Fetal Medicine

Department of Obstetrics and Gynecology

The Ottawa Hospital

Ottawa, Ontario, Canada [26, 27]

Obstetrics and Gynecology at the Ottawa Hospital Although

modern medicine relies heavily on science and technology,

the most astute accoucheurs still practice the art of obstetrics

embraced in this book Much has changed, but much has

re-mained the same Although every chapter has been revised and

refreshed, we’ve endeavored to stay true to the utilitarian spirit

of the book that Dr Oxorn intended This textbook is not a

treatise on theoretical evidence-based obstetrics that can only

be practiced at tertiary centers; rather, it is a handbook of

use-ful information for practitioners in the trenches who need real

advice on how to manage real problems New additions, such

as a chapter on the challenges of obesity in pregnancy,

descrip-tions of modern techniques for the management of postpartum

hemorrhage, and an expanded treatment of multiples, refl ect

the modernization of Dr Oxorn’s work

It has always been our intention to bring this text into the

twenty-fi rst century while respecting its heritage As such, we

owe a great debt to the previous contributors for giving us

such a solid foundation; their legacy resides both within these

pages as well as in the halls of the labor wards in Ottawa

happen

The innominate bones are placed laterally and anteriorly Each is formed

by the fusion of three bones—the ilium, ischium, and pubis—around the acetabulum

Ilium

The ilium is the superior bone: It has a body (which is fused with the ischial body) and an ala Points of note concerning the ilium include:

1 The anterior superior iliac spine gives attachment to the inguinal ligament

2 The posterior superior iliac spine marks the level of the second sacral vertebra Its presence is indicated by a dimple in the overlying skin

3 The iliac crest extends from the anterior superior iliac spine to the posterior superior iliac spine

Ischium

The ischium consists of a body in which the superior and inferior rami merge

1 The body forms part of the acetabulum

2 The superior ramus is posterior and inferior to the body

3 The inferior ramus fuses with the inferior ramus of the pubis

4 The ischial spine separates the greater sciatic from the lesser sciatic notch It is an important landmark Part of the levator ani muscle is attached to it

5 The ischial tuberosity is the inferior part of the ischium and is the bone

on which humans sit

Pubis

The pubis consists of the body and two rami

1 The body has a rough surface on its medial aspect This is joined to the corresponding area on the opposite pubis to form the symphysis pubis The levator ani muscles are attached to the pelvic aspect of the pubis

CLINICAL ANA

2 The pubic crest is the superior border of the body

3 The pubic tubercle, or spine, is the lateral end of the pubic crest The inguinal ligament and conjoined tendon are attached here

4 The superior ramus meets the body of the pubis at the pubic spine and the body of the ilium at the iliopectineal line, where it forms a part of the acetabulum

5 The inferior ramus merges with the inferior ramus of the ischium

Landmarks can be identified:

1 The iliopectineal line extends from the pubic tubercle back to the

sac-roiliac joint It forms the greater part of the boundary of the pelvic inlet

2 The greater sacrosciatic notch is between the posterior inferior iliac spine superiorly and the ischial spine inferiorly

3 The lesser sacrosciatic notch is bounded by the ischial spine superiorly and the ischial tuberosity inferiorly

4 The obturator foramen is delimited by the acetabulum, the ischial rami, and the pubic rami

The sacral promontory is the anterior superior edge of the first sacral vertebra It protrudes slightly into the cavity of the pelvis, reducing the anteroposterior diameter of the inlet

Coccyx

The coccyx (tail bone) is composed of four rudimentary vertebrae The superior surface of the first coccygeal vertebra articulates with the inferior surface of the fifth sacral vertebra to form the sacrococcygeal joint Rarely, there is fusion between the sacrum and coccyx, with resultant limitation

of movement

The coccygeus muscle, levator ani muscles, and sphincter ani externus are attached to the anterior aspect of the coccyx They are important to pelvic floor function

PELVIC JOINTS AND LIGAMENTS

The sacrum, coccyx, and two innominate bones are linked by four joints: the symphysis pubis, the sacrococcygeal, and the two sacroiliac synchondroses (Fig 1-1)

Sacroiliac Joint

The sacroiliac joint lies between the articular surfaces of the sacrum and the ilium The weight of the body is transmitted through it to the pelvis and then to the lower limbs It is a synovial joint and permits a small degree of movement The capsule is weak, and stability is maintained by the muscles around it as well as by four primary and two accessory ligaments

I l iaccrest

Acetabulum Obturator foramen

Inf ramus of pubis Ischial tuberosity Ischial

spine

Greater sciatic notch

Post sup iliac spine Sacrum

Coccyx Sacral promontory

Ant sacroiliac lig.

2 The interosseus sacroiliac ligaments are short, strong transverse bands that extend from the rough part behind the auricular surface on the ilium to the adjoining area on the sacrum

3 The short posterior sacroiliac ligaments are strong transverse bands that lie behind the interosseus ligaments

4 The long posterior sacroiliac ligaments are each attached to the posterosuperior spine on the ilium and to the tubercles on the third and fourth sacral vertebrae

Accessory Ligaments

1 The sacrotuberous ligaments are attached on one side to the posterior superior iliac spine; posterior inferior iliac spine; tubercles on the third, fourth, and fifth sacral vertebrae; and lateral border of the coccyx On the other side, the sacrotuberous ligaments are attached to the pelvic aspect of the ischial tuberosity

2 The sacrospinous ligament is triangular The base is attached to the

lat-eral parts of the fifth sacral and first coccygeal vertebrae, and the apex

is attached to the ischial spine

Sacrococcygeal Joint

The sacrococcygeal joint is a synovial hinge joint between the fifth sacral and the first coccygeal vertebrae It allows both flexion and extension Extension, by increasing the anteroposterior diameter of the outlet of the pelvis, plays an important role in parturition Overextension during delivery may break the small cornua by which the coccyx is attached to the sacrum This joint has a weak capsule, which is reinforced by anterior, posterior, and lateral sacrococcygeal ligaments

Symphysis Pubis

The symphysis pubis is a cartilaginous joint with no capsule and no synovial membrane Normally, there is little movement The posterior and superior ligaments are weak The strong anterior ligaments are reinforced

by the tendons of the rectus abdominis and the external oblique muscles The strong inferior ligament in the pubic arch is known as the arcuate pubic ligament It extends between the rami and leaves a small space in the subpubic angle.

MOBILITY OF PELVIS

During normal pregnancy, under the influence of progesterone and relaxin, there is increased flexibility of the sacroiliac joints and the sym-physis pubis Hyperemia and softening of the ligaments around the joints also take place The pubic bones may separate by 1 to 12 mm Excessive mobility of the symphysis pubis leads to pain and difficulty in walking

It has been shown that, besides the local changes that may take place in the pelvic ligaments, a generalized change in the laxity of joints occurs in pregnancy

MALE AND FEMALE PELVISES

At birth, there is no difference between male and female pelvises Sexual dimorphism does not take place until puberty A female pelvis develops in offspring born with no gonads Thus, ovaries and estrogen are not neces-sary for the formation of the female-type pelvis, but the presence of a testis that is producing androgen is essential for development of the male-type pelvis

ADOLESCENCE

Adolescent girls’ pelvises are smaller than those of mature women The pattern of growth of the pelvic basin is different from that of bodily stature Among girls, the growth in stature decelerates rapidly in the first year after menarche and ceases within 1 or 2 years The pelvic basin, on the other hand, grows more slowly and more steadily during late adolescence At the same time, it changes from an anthropoid to a gynecoid configuration Thus, maturation of the reproductive system and attainment of adult size do not indicate that the growth and development of the pelvis are complete The smaller pelvic capacity in adolescent girls may contribute to the higher incidence of cephalopelvic disproportion and other dystocias in primigravidous girls younger than the age of 15 years

CHAPTER 2

The Pelvic Floor

Dante Pascali

THE PELVIC FLOOR

The pelvic floor (Fig 2-1) is a muscular diaphragm that separates the pelvic cavity above from the perineal space below It is formed

by the levator ani and coccygeus muscles and is covered completely

by parietal fascia

The urogenital hiatus is an anterior gap through which the urethra and vagina pass The rectal hiatus is posterior, and the rectum and anal canal pass through it

PELVIC FLOOR FUNCTIONS

1 The pelvic floor supports the pelvic viscera in humans

2 To build up effective intraabdominal pressure, the muscles of the diaphragm, abdominal wall, and pelvic floor must contract together

3 During parturition, the pelvic floor helps the anterior rotation of the presenting part and directs it downward and forward along the birth passage

Urethra Vagina Rectum

Obturator int m.

White line of pelvic fascia

Ischiococcygeus

Iliococcygeus Pubococcygeus Puborectalis Pubovaginalis

FIgURE 2-1 Pelvic floor.

CLINICAL ANA

PELVIC FLOOR MUSCLES

1 Levators ani, each composed of two muscles:

and pubococcygeus proper

b Iliococcygeus

2 Coccygeus (ischiococcygeus)

Levator Ani Muscle

The levator ani muscle has a lateral origin and a central insertion, where

it joins with the corresponding muscle from the other side The direction

of the muscle from origin to insertion is inferior and medial The origin of each levator ani is from the:

1 Posterior side of the pubis

2 Arcuate tendon of the pelvic fascia (the white line of the pelvic fascia)

3 Pelvic aspect of the ischial spine

The insertion, from anterior to posterior, is into:

The pubococcygeus is the most important, most dynamic, and most

spe-cialized part of the pelvic floor It lies in the midline; is perforated by the urethra, vagina, and rectum; and is often damaged during delivery It origi-

nates from the posterior side of the pubis and from the white line of the pelvic fascia anterior to the obturator canal The muscle passes posterior and medially in three sections: (1) pubovaginalis, (2) puborectalis and (3) pubococcygeus proper

Pubovaginalis Muscle The most medial section of the pubococcygeus, this muscle is shaped like a horseshoe, open anteriorly The fibers make contact and blend with the muscles of the urethral wall, after which they

form a loop around the vagina They insert into the sides and back of the vagina and into the central point of the perineum.

The principal function of the pubovaginalis is to act as a sling for the vagina Since the vagina helps to support the uterus and appendages, bladder and urethra, and rectum, this muscle is the main support of the female pelvic organs Tearing or overstretching predisposes to uterovaginal prolapse The muscle also functions as the vaginal sphincter, and when it goes into spasm, the condition is called vaginismus

Puborectalis Muscle The intermediate part of the pubococcygeus, this muscle forms a loop around the anal canal and rectum The inser-tion is into the lateral and posterior walls of the anal canal between the sphincter ani internus and externus, with whose fibers the puborectalis joins It inserts also in the anococcygeal body

The puborectalis suspends the rectum, but since this organ does not support the other pelvic viscera, the puborectalis plays a small role

in holding up the pelvic structures The main work of this muscle is in controlling the descent of feces and in so doing it acts as an auxiliary sphincter for the anal canal When the anococcygeal junction is pulled forward, the puborectalis increases the anorectal flexure and slows the descent of feces

Pubococcygeus Proper This muscle is composed of the most lateral fibers of the pubococcygeus muscle It has a Y-shaped insertion into the lateral margins of the coccyx When it contracts, it pulls the coccyx ante-riorly, increasing the anorectal juncture Thus, in combination with the external sphincter ani, it helps control the passage of feces

Iliococcygeus Muscle

The iliococcygeus muscles arise from the white line of the pelvic fascia posterior to the obturator canal They join with the pubococcygeus muscle proper and insert into the lateral margins of the coccyx These are less dynamic than the pubovaginalis and act more like a musculo-fascial layer

Ischiococcygeus Muscle

The ischiococcygeus or coccygeus muscles originate from the ischial spines and insert into the lateral borders of the coccyx and the fifth sacral vertebra These muscles supplement the levators ani and occupy most of the posterior portion of the pelvic floor

CLINICAL ANA

PELVIC FLOOR DURINg PARTURITION

When the presenting part has reached the proper level during the second stage of labor, the central point of the perineum becomes thin The levator ani muscles and the anal sphincter relax, and the muscles of the pelvic floor are drawn over the advancing head Tearing and overstretching these muscles weaken the pelvic floor and may cause extensive damage

CHAPTER 3

Perineum

Dante Pascali

The perineum is a diamond-shaped space that lies below the pelvic floor (Fig 3-1) Its boundaries are as follows:

1 Superiorly: the pelvic floor made up of the levator ani muscles and the coccygei

2 Laterally: the bones and ligaments that make up the pelvic outlet; from front to back, these are the subpubic angle, ischiopubic rami, ischial tuberosities, sacrotuberous ligaments, and coccyx

3 Inferiorly: the skin and fascia

This area is divided into two triangles: anteriorly, the urogenital triangle; posteriorly, the anal triangle These are separated by a transverse band composed of the transverse perineal muscles and the base of the urogenital diaphragm

Superficial transverse perineal m Bulbocavernosus m.

Vagina Urethra Ischiocavernosus m.

FIGURE 3-1 Perineum.

CLINICAL ANA

1 Anteriorly: by the subpubic angle

2 Laterally: by the ischiopubic rami and the ischial tuberosities

3 Posteriorly: by the transverse perineal muscles and the base of the urogenital diaphragm

The urogenital triangle contains:

1 Opening of the vagina

2 Terminal part of the urethra

3 Crura of the clitoris with the ischiocavernosus muscles

4 Vestibular bulbs (erectile tissue) covered by the bulbocavernosus muscles

5 Bartholin’s glands and their ducts

6 Urogenital diaphragm

7 Muscles that constitute the central point of the perineum (perineal body)

8 Perineal pouches, superficial and deep

9 Blood vessels, nerves, and lymphatics

Urogenital Diaphragm

The urogenital diaphragm (triangular ligament) lies in the anterior triangle

of the perineum It is composed of muscle tissue covered by fascia

1 The two muscles are the deep transverse perineal and the sphincter of the membranous urethra

2 The superior layer of fascia is thin and weak

3 The inferior fascial layer is a strong fibrous membrane It extends from a short distance beneath the arcuate pubic ligament to the ischial tuberosities The fascial layers fuse superiorly and form the trans-

verse perineal ligament Inferiorly, they join in the central point of the perineum

The deep dorsal vein of the clitoris lies in a small space between the apex

of the urogenital diaphragm and the arcuate pubic ligament Through the diaphragm pass the urethra, the vagina, blood vessels, lymphatics, and nerves

Superficial Perineal Pouch

The superficial perineal pouch is a space that lies between the inferior layer of the urogenital diaphragm and Colles fascia

Superficial Transverse Perineal Muscles

The superficial transverse perineal muscles are the superficial parts of the deep muscles and have the same origin and insertion These are outside the urogenital diaphragm Sometimes they are entirely lacking

Ischiocavernosus Muscles

The ischiocavernosus muscles cover the clitoral crura The origin of each is the inferior ramus of the pubis, and they insert at the lateral aspect of the crus These muscles compress the crura and by blocking the venous return cause the clitoris to become erect

Bulbocavernosus Muscle

The bulbocavernosus muscle surrounds the vagina With the external anal sphincter, it makes a figure eight around the vagina and rectum It is also called the bulbospongiosus It originates from the central point of the perineum and inserts into the dorsal aspect of the clitoral body The muscle passes around the orifice of the vagina and surrounds the bulb of the vestibule.The bulbocavernosus muscle compresses the erectile tissue around the vaginal orifice (bulb of the vestibule) and helps in clitoral erection by clos-ing its dorsal vein It acts as a weak vaginal sphincter The real sphincter

of the vagina is the pubovaginalis section of the levator ani

Deep Perineal Pouch

The deep perineal pouch lies between the two fascial layers of the urogenital diaphragm

Sphincter of the Membranous Urethra

The sphincter of the membranous urethra lies between the fascial layers

of the urogenital diaphragm It is also called the compressor of the urethra.

The voluntary fibers have their origin from the inferior rami of the ischium and pubis They join with the deep transverse perineal muscles Their action is to expel the last drops of urine

The involuntary fibers surround the urethra and act as its sphincter

Deep Transverse Perineal Muscles

The deep transverse perineal muscles lie between the layers of fascia of the urogenital diaphragm They blend with the sphincter of the membranous urethra The origin is the ischiopubic ramus on each side, and they insert

at the central point of the perineum (perineal body)

CLINICAL ANA

ANAL TRIANGLE

The anal triangle is bounded:

1 Anteriorly: by the transverse perineal muscles and the base of the urogenital diaphragm

2 Laterally: by the ischial tuberosities and the sacrotuberous ligaments

3 Posteriorly: by the coccyx

The anal triangle contains the following:

1 Lower end of the anal canal and its sphincters

2 Anococcygeal body

3 Ischiorectal fossa

4 Blood vessels, lymphatics, and nerves

Sphincter Ani Externus

The sphincter ani externus has two parts

1 The superficial portion surrounds the anal orifice Its fibers are

volun-tary and act during defecation or in an emergency The origin is the tip of the coccyx and the anococcygeal body Insertion is in the central point of the perineum

2 The deep part is an involuntary muscle that surrounds the lower part of the anal canal and acts as a sphincter for the anus It blends with the levators ani and the internal anal sphincter When inactive, the deep circular fibers are in a state of tonus, occluding the anal orifice

Anococcygeal Body

The anococcygeal body is composed of muscle tissue (levators ani and external sphincter ani) and fibrous tissue It is located between the tip of the coccyx and the anus

PERINEAL BODY

The central point of the perineum or perineal body lies between the posterior angle of the vagina in front and the anus behind In obstetrics, it

is referred to as the perineum It is often torn during delivery The following muscles meet to form this structure:

1 Sphincter ani externus

2 Two levator ani muscles

3 Superficial and deep transverse perineal muscles

4 Bulbocavernosus muscle

CHAPTER 4

Uterus and

Vagina

Dante Pascali