NOTES ON OB Nursing
NORMAL LABOR (THEORIES OF LABOR ONSET)
1. Oxytocin Stimulation Theory
2 .Uterine Stretch Theory
3. Progesterone Deprivation Theory
4. Prostaglandin Theory
5. Theory of the Aging Placenta
6 .Fetal Adrenal Response Theory
SIGNS OF LABOR (WRISLIR)
• Weight Loss – 2-3 pounds (progesterone)
• Ripening of the Cervix – “soft”
• Increased Braxton Hicks – “irregular, painless”
• Show – “ruptured capillaries + operculum = pinkish color”
• Lightening – “the baby dropped” - 2 weeks (primi) and before or during (multi)
● Relief of respiratory discomfort
● Increased frequency of urination
● Leg pains
● Muscle spasms
● Increased vaginal discharge
● Decreased fundal height
• Increased Level of Activity – large amount of epinephrine (AG)
• Rupture of Membranes – gush or steady trickle of clear fluid
FALSE LABOR CANDAC
✓ Contraction disappear with ambulation
✓ Absence of cervical dilation
✓ No ↑ DIF (duration, intensity, frequency)
✓ Discomfort @ abdomen
✓ Absence of show
✓ Contraction stops when sedated TRUE LABOR CUPPAD
✓ Contraction persists when sedated
✓ Uterine contraction ↑ DIF (duration, intensity, frequency)
✓ Progressive cervical dilation
✓ Presence of show
✓ Ambulation increase contractions
✓ Discomfort radiates to lumbosacral area
✓ LENGTH OF LABOR STAGE OF LABOR PRIMI (VIRGIN)
MULTI (DIS-VIRGIN) 1ST STAGE 10 – 12 HOURS 6 – 8 HOURS 2ND STAGE 30 MINS – 2
HOURS Ave: 50 mins 20 – 90 MINS Ave: 20 mins 3RD STAGE 5 – 20 MINS 5 – 20 MINS
4TH STAGE 2 – 4 HOURS 2 – 4 HOURS
ESSENTIAL FACTORS OF LABOR (5Ps)
1. Passages
2. Power
3. Passenger
4. Person
5. Position
PASSAGES FUNCTIONS (Sit Sit) ○ Serves as birthcanal ○ It proves attachment to muscles,
fascia and ligaments ○ Supports uterus during pregnancy ○ It provides protection to the organs
found within the pelvic cavity
TYPES (GAPA) ○ Gynecoid – normal female type of pelvis - most ideal for childbirth - round
shape, found in 50% of women
○ Android – male pelvis - presents the most difficulty during childbirth - found in 20% of
women
○ Platypelloid – flat pelvis, rarest, occurs to 5% of women
○ Anthropoid – apelike pelvis, deepest type of pelvis found in 25% of women
DIVISION OF PELVIS
1. False Pelvis – “provide and direct”
2. True Pelvis – “the tunnel” IPO
○ Inlet or Pelvic Brim – entrance to true pelvis
ANTEROPOSTERIOR DIAMETER DOT
1. Diagonal Conjugate – midpoint of sacral promontory to the lower margin of symphysis pubis
(12.5 cm)
2. Obstetric Conjugate – midpoint of sacral promontory to the midline of symphysis pubis (11
cm)
3. True Conjugate – midpoint of sacral promontory to the upper margin of symphysis pubis (11.5
cm)
○ Pelvic Canal – situated between inlet and outlet - designed to control the speed of descent of
the fetal head
○ Outlet – most important diameter of the outlet.
POWERS 3I’s
⦿ Involuntary – not within the control of the parturient
⦿ Intermittent – alternating contraction and relaxation
⦿ Involves discomfort (compression, stretching and hypoxia)
⦿ PHASES OF UTERINE CONTRACTIONS 1. Increment/Crescendo – “ready, get set” 2.
Acme/Apex – “go” 3. Decrement/Decrescendo – “stop”
⦿ INTENSITY - strength of uterine contraction ○ Mild – slightly tensed fundus ○ Moderate –
firm fundus ○ Strong – rigid, board like fundus
⦿ FREQUENCY – rate of uterine contraction - measured from the beginning of a contraction to
the beginning of the next contraction
⦿ DURATION – length of uterine contraction - measured from the beginning of a contraction to
the end of the same contraction
⦿ INTERVAL – measured from the end of contraction to the beginning of the next contraction
PASSENGER
⦿ HEAD (BOTu) - Biggest part of the fetal body - Olways the presenting part - Turn to present
smallest diameter
⦿ CRANIAL BONES 1 FOSE, 2 PaTe 1 frontal bone2 parietal bone 1 occipital bone2 temporal
bone 1 sphenoid bone 1 ethmoid bone
⦿ SUTURE LINES – allow skull bones to overlap (molding) and for further brain development
(SFC La) ● Sagittal Suture – between 2 parietal bones
● Frontal Suture – between 2 frontal bones
● Coronal Suture – between frontal and parietal
● Lamdiodal Suture – between parietal and occipital
⦿ FONTANELS – intersection of suture lines
● Anterior Fontanel or Bregma – intersection of SFC - diamond shaped, closes b/n 12 – 18
months - 3 x 4 cm
● Posterior Fontanel or Lambda – intersection of Sla- triangular shaped, closes b/n 2 – 3 months
⦿ DIAMETERS OF THE FETAL HEAD AP > T (fetal head)
1.Tranverse Diameters BBB
● Biparietal – most important TD - greatest diameter presented to the pelvic inlet’s AP and at
the outlet’s TD - average measurement is 9.5 cm
● Bitemporal – average measurement is 8 cm
● Bimastoid – average measurement is 7 cm 2. Anteroposterior Diameters SOO
● Suboccipitobregmatic – smallest APD - fully flexed (presenting part) - measured from the
inferior aspect of occiput to the anterior fontanel - average measurement is 9.5 cm
● Occipitofrontal – head partially extended and presenting part