Normal labor and delivery

1. Normal Labor and Delivery
Presented by
Ahmed Mahmood
Reviewed by
Dr. Nazneen
OB/GYN rotation

2. Definition
• The World Health Organization
(WHO) defines normal birth as
"spontaneous in onset, low-risk at
the start of labor and remaining so
throughout labor and delivery. The
infant is born spontaneously in the
vertex position between 37 and 42
completed weeks of pregnancy.
After birth, mother and infant are
in good condition"
• Stages of normal labor:

3. Lie and Attitude
• Lie: describes how the fetus is
oriented to the mother’s spine
• Attitude: The fetal attitude is
normally one of flexion, with the
head flexed forward and the
arms and the legs flexed. The
flexed fetus is compact and
ovoid and most efficiently
occupies the space in the
mother’s uterus and pelvis.
Extension of the head, the arms,
and/or the legs sometimes
occurs, and labor may be
prolonged.

4. Presentation
Presentation refers to the fetal part that enters the
pelvis first. The cephalic presentation is the most
common. Any of the following four variations of
cephalic presentations can occur, depending on the
extent to which the fetal head is flexed
• 1. Vertex presentation: The fetal head is fully flexed.
This is the most favorable cephalic variation because
the smallest possible diameter of the head enters the
pelvis. It occurs in about 96% of births.
• 2. Military presentation: The fetal head is neither
flexed nor extended.
• 3. Brow presentation: The fetal head is partly
extended. The longest diameter of the fetal head is
presenting. This presentation is unstable and tends
to convert to either a vertex or a face presentation.
• 4. Face presentation: The head is fully extended and
the face presents.

5. Position
• Position refers to how a reference point
on the fetal presenting part is oriented
within the mother’s pelvis. The
term occiput is used to describe how the
head is oriented if the fetus is in a
cephalic vertex presentation. The
term sacrum is used to describe how a
fetus in a breech presentation is oriented
within the pelvis. The shoulder and back
are reference points if the fetus is in a
shoulder presentation.
• The maternal pelvis is divided into four
imaginary quadrants: right and left
anterior and right and left posterior.

6. Mechanisms of Labor
The mechanisms of labor, also known as the cardinal movements, involve
changes in the position of the fetus’s head during its passage in labor.
These are described in relation to a vertex presentation. Although labor
and delivery occurs in a continuous fashion, the cardinal movements are
described as the following 7 discrete sequences:
1. Engagement
2. Descent
3. Flexion
4. Internal rotation
5. Extension
6. Restitution and external rotation
7. Expulsion

7. Engagement and Descent
Engagement
• The widest diameter of the presenting part (with a
well-flexed head, where the largest transverse
diameter of the fetal occiput is the biparietal diameter)
enters the maternal pelvis to a level below the plane of
the pelvic inlet. On the pelvic examination, the
presenting part is at 0 station, or at the level of the
maternal ischial spines.
Descent
• The downward passage of the presenting part through
the pelvis. This occurs intermittently with contractions.
The rate is greatest during the second stage of labor.

8. • Flexion The fetal head should be flexed to pass most easily through the pelvis. As labor
progresses, uterine contractions increase the amount of fetal head flexion until the fetal
chin is on the chest.
• Internal Rotation When the fetus enters the pelvis head first, the head is usually oriented
so the occiput is toward the mother’s right or left side. As the fetus is pushed downward
by contractions, the curved, cylindrical shape of the pelvis causes the fetal head to turn
until the occiput is directly under the symphysis pubis (occiput anterior [OA]).
• Extension As the fetal head passes under the mother’s symphysis pubis, it must change
from flexion to extension so it can properly negotiate the curve. To do this, the fetal neck
stops under the symphysis, which acts as a pivot. The head swings anteriorly as it extends
with each maternal push until it is born.
• External Rotation When the head is born in extension, the shoulders are crosswise in the
pelvis and the head is somewhat twisted in relation to the shoulders. The head
spontaneously turns to one side as it realigns with the shoulders (restitution). The
shoulders then rotate within the pelvis until their transverse diameter is aligned with the
mother’s anteroposterior pelvis. The head turns farther to the side as the shoulders rotate
within the pelvis.
• Expulsion The anterior shoulder and then the posterior shoulder are born, quickly
followed by the rest of the body.

9. Normal Childbirth
• The specific event that triggers the onset of labor remains unknown.
Many factors probably play a part in initiating labor, which is an
interaction of the mother and fetus. These factors include stretching
of the uterine muscles, hormonal changes, placental aging, and
increased sensitivity to oxytocin. Labor normally begins when the
fetus is mature enough to adjust easily to life outside the uterus yet
still small enough to fit through the mother’s pelvis. This point is
usually reached between 38 and 42 weeks after the mother’s last
menstrual period

10. Signs of Impending Labor
• Signs and symptoms that labor is about to start may occur from a few hours to a few
weeks before the actual onset of labor.
• Braxton Hicks Contractions: irregular contractions that begin during early pregnancy and
intensify as full term approaches. Although they are often called “false” labor, they play a
part in preparing the cervix to dilate and in adjusting the fetal position within the uterus.
• Increased Vaginal Discharge
• Bloody Show: is thick mucus mixed with pink or dark brown blood. It may begin a few
days before labor, or a woman may not have bloody show until labor is under way.
Bloody show may also occur if the woman has had a recent vaginal examination or
intercourse.
• Rupture of the Membranes
• Energy Spurt
• Weight Loss

11. First stage of labor
• The first stage begins with regular uterine contractions and ends with complete cervical
dilatation at 10 cm.
• subdivided into:
1. An early latent phase begins with mild, irregular uterine contractions that soften and
shorten the cervix. The contractions become progressively more rhythmic and
stronger.
2. And an ensuing active phase begins at about 3-4 cm of cervical dilation and is
characterized by rapid cervical dilation and descent of the presenting fetal part. The
first stage of labor ends with complete cervical dilation at 10 cm. further divided into:
acceleration phase, phase of maximum slope & deceleration phase.

12. Intrapartum management of the
First Stage of Labor
• On admission to the Labor and Delivery suite, a woman having normal labor should be
encouraged to
• assume the position that she finds most comfortable. Possibilities including the following:
1. Walking
2. Lying supine
3. Sitting
4. Resting in a left lateral decubitus position
Management includes the following:
• Periodic assessment of the frequency and strength of uterine contractions and changes in cervix
and in the fetus' station and position
• Monitoring the fetal heart rate at least every 15 minutes, particularly during and immediately
afteruterine contractions; in most obstetric units, the fetal heart rate is assessed continuously

13. Second stage of labor
• The second stage begins with
complete cervical dilatation and ends
with the delivery of the fetus. The
American College of Obstetricians and
Gynecologists (ACOG) has suggested
that a prolonged second stage of labor
should be considered when the
second stage of labor exceeds 3 hours
if regional anesthesia is administered
or 2 hours in the absence of regional
anesthesia for nulliparas. In
multiparous women, such a diagnosis
can be made if the second stage of
labor exceeds 2 hours with regional
anesthesia or 1 hour without it.

14. Intrapartum Management of Labor
2nd Stage of Labor
• With complete cervical dilatation, the fetal heart rate should be
monitored or auscultated at least every 5 minutes and after each
contraction.
• Prolonged duration of the second stage alone does not mandate
operative delivery if progress is being made, but management options
for second-stage arrest include the following:
1. Continuing observation/expectant management
2. Operative vaginal delivery by forceps or vacuum-assisted vaginal
delivery, or cesarean delivery.

15. Delivery of the fetus
• Positioning of the mother for delivery can be any of the following:
1. Supine with her knees bent (ie, dorsal lithotomy position; the usual
choice)
2. Lateral (Sims) position
3. Partial sitting or squatting position
4. On her hands and knees
• Episiotomy used to be routinely performed at this time, but current
recommendations restrict its use to maternal or fetal indications
• Delivery maneuvers

16. Delivery maneuvers
• The head is held in mid position until it is delivered, followed by suctioning of the
oropharynx and nares
• Check the fetus's neck for a wrapped umbilical cord, and promptly reduce it if possible
• If the cord is wrapped too tightly to be removed, the cord can be double clamped and
cut
• The fetus's anterior shoulder is delivered with gentle downward traction on its head and
chin
• Subsequent upward pressure in the opposite direction facilitates delivery of the posterior
shoulder
• The rest of the fetus should now be easily delivered with gentle traction away from the
mother
• If not done previously, the cord is clamped and cut
• The baby is vigorously stimulated and dried and then transferred to the care of the
waiting attendants or placed on the mother's abdomen

17. The third stage
• The following 3 classic signs indicate that the placenta has separated
from the uterus:
• The uterus contracts and rises
• The umbilical cord suddenly lengthens
• A gush of blood occurs
• Delivery of the placenta usually happens within 5-10 minutes after
delivery of the fetus, but it is
• considered normal up to 30 minutes after delivery of the fetus.

18. Intrapartum Management of Labor
• Two methods of augmenting labor have been established. The traditional method
involves the use of low doses of oxytocin with long intervals between dose
increments. For example, low-dose infusion of oxytocin is started at 1 mili IU/min
and increased by 1-2 mili IU/min every 20-30 minutes until adequate uterine
contraction is obtained.
• The second method, or active management of labor, involves a protocol of clinical
management that aims to optimize uterine contractions and shorten labor. This
protocol includes strict criteria for admission to the labor and delivery unit, early
amniotomy, hourly cervical examinations, early diagnosis of inefficient uterine
activity (if the cervical dilation rate is < 1.0 cm/h), and high-dose oxytocin infusion
if uterine activity is inefficient. Oxytocin infusion starts at 4 mili IU/min (or even 6
mili IU/min) and increases by 4 mili IU/min (or 6 mili IU/min) every 15 minutes
until a rate of 7 contractions per 15 minutes is achieved or until the maximum
infusion rate of 36 mili IU/min is reached.

19. Pain control
• Laboring women often experience intense pain. Uterine contractions result in visceral pain, which
is innervated by T10-L1. While in descent, the fetus' head exerts pressure on the mother's pelvic
floor, vagina, and perineum, causing somatic pain transmitted by the pudendal nerve (innervated
by S2-4).[4] Therefore, optimal pain control during labor should relieve both sources of pain.
• Agents given in intermittent doses for systemic pain control include the following:
• Meperidine, 25-50 mg IV every 1-2 hours or 50-100 mg IM every 2-4 hours
• Fentanyl, 50-100 mcg IV every hour
• Nalbuphine, 10 mg IV or IM every 3 hours
• Butorphanol, 1-2 mg IV or IM every 4 hours
• Morphine, 2-5 mg IV or 10 mg IM every 4 hours
• As an alternative, regional anesthesia may be given. Anesthesia options include the following:
1. Epidural
2. Spinal
3. Combined spinal-epidural

20. References
• Up-to-date
• Medscape
Thank You
Ahmed Mahmood