Maternal Factors that may Trigger Labor
stretching -> release of prostaglandins
pressure on cervix -> release of oxytocin -> UC
estrogen increases
oxytocin and prostaglandins work together -> activating UC
Fetal Factors that may Trigger Labor
placental age
prostaglandins made by fetal membrane -> UC
fetal cortisol rises and acts on placenta to reduce progesterone that quiets uterus -> increases prostaglandins that stimulate UC
Premonitory Signs of Labor
lightening: descent of the fetus into the true pelvis (2wks before term in first pregnancies, during labor in subsequent pregnancies)
Braxton-Hicks contractions: irregular UC that coordinate the many muscle layers of the uterus preparing them for labor
Bloody show: blood tinged cervical mucus as the cervix is changing
Rupture of membranes (ROM): rupture more than hour before onset of contractions
*GBS-: can give them time after water breaks if they want to wait at home as long as fluid was clear (no meconium)
GBS+: pt needs to come to hospital so you can start with prophylactic antibiotics to treat before birth
Assessing for Rupture of Membranes (ROM)
- sterile speculum exam to assess for vaginal pooling
- nitrazine: paper turns blue/black when in contact w/ amniotic fluid
- ferning: sample of fluid is taken and allowed to dry on a microscope slide if it has amniotic fluid will exhibit ferning pattern
Factors Affecting Labor
5 Ps Power (the contraction) Passage (the pelvis) Passenger (the fetus) Psyche (the response of woman) Position (maternal postures and physical positions to facilitate labor
Powers
UC -> cervical dilation (opening) and effacement (thinning) in the first stage of labor
Passage
greatest determinant in vaginal delivery of a fetus
true pelvis (inlet, midpelvis, and outlet)
size and type of maternal pelvis
ability of cervix to dilate and efface
ability of vaginal canal to distend
Passenger
Fetus and its relationship to the passageway, includes:
- fetal skull
- fetal attitude (chin tucked preferred)
- fetal lie
- fetal presentation (cephalic is preferred)
- fetal position
- fetal size
Fetal Head
biparietal diameter: largest transverse measurement and an important indicator of head size
molding: overlapping bones that allow skull to pass through narrow parts of maternal pelvis
sutures: membranous joints uniting cranial bones, allow for molding, used to identify positioning of the fetal head during a vaginal exam
Fetal Head Landmarks
Sagittal suture
fontanelles (anterior, diamond shape is larger)
vertex: area between anterior and posterior fontanelles
occiput: occipital bone, beneath the posterior fontanelle
Fetal Attitude
relationship of fetal body parts to one another (flexion or extension)
normal attitude = general flexion
- head flexed, chin on chest
- arms crossed over chest
- legs flexed at knee, thighs on abdomen
Fetal Lie
relationship of long axis (spine) of fetus and long axis (spine) of mother or cephalocaudal axis
- longitudinal: vertical (parallel relationship)
- transverse: horizontal (perpendicular relationship) *cannot be delivered in this lie
- oblique: diagonal
Fetal Presentation
presenting part (part or pole that enters the pelvis first)
- cephalic ~95% of births
- breech
Relationship of Maternal Pelvis and Presenting Part
station: narrowest part of pelvis between ischial spines = 0 station
- presenting part moves from -5 to +5
engagement: largest diameter of presenting part through pelvic inlet (for vertex this is the biparietal diameter)
- floating
- dipping
Fetal Position
describe the fetal position is the relation of the denominator or reference point to the maternal pelvis
6 positions for each presentation (right and left anterior, posterior, and transverse)
1st letter = R or L of woman’s pelvis (which side fetal spine is on)
2nd letter = fetal part presenting (occiput, mentum, sacrum, acromion)
3rd letter = position that the above fetal part is facing (anterior, posterior, or transverse)
Psyche
psyche of mom
- preparation for childbirth
- expectations from birth
- sense of security and safety
- supports
- cultural beliefs, values, expectations
*can influence labor progress
Positioning
positioning of mom
integral component as it has an effect on both the anatomical and physiological adaptations to labor
1st stage of labor = upright position (walking, sitting, kneeling or squatting)
2nd stage of labor = upright position (increases the pelvic outlet and better aligns the fetus with the the pelvic inlet)
True Labor
contractions do not decrease with rest or with warm tub bath
- progressive dilation and effacement
- regular contractions (increasing in frequency, duration, intensity - intensity increase w/ ambulation)
- pain starts in back and radiates to abdomen
- pain not relieved by ambulation or rest
False Labor
lack of appreciable cervical effacement and dilation
- irregular contractions (do not increase in frequency, duration, and intensity)
- contractions mainly in lower abdomen and groin
- hydration or sedation may slow or stop contractions
- pain may be relieved by ambulation, changes of position, resting, or hot bath or shower
Stages of Labor
Stage 1:
- latent - contractions are spread apart and until women is 3cm dilated
- active: until 7cm dilated
- transition: until 10cm
Stage 2: begins w/ complete cervical dilation and ends with delivery of baby
Stage 3: begins after delivery of baby, ends with delivery of placenta
Stage 4: begins after delivery of placenta and is completed 4 hours later
Latent Phase: Nursing Actions
- admit and orient to labor room
- review birth plan
- teach/reinforce relaxation and breathing techniques
- obtain labs, start IV, GBS prophylaxis PRN
- provide comfort measures
Active Phase: Nursing Actions
- monitor FHR and maternal VS
- reassess pain, monitor effectiveness of pain meds if given
- I&O
- incorporate support person
- encourage breathing and relaxation techniques
- explain progress
- provide reassurance
Transition Phase: Nursing Actions
- FHR assessment
- support and encourage breathing
- promote comfort
- prepare for delivery
*exhaustion and bloody show starts in this phase
GBS Prophylaxis
women screened for GBS ~35-37wks by culture
prophylaxis indicated for:
- positive culture
- GBS bacteruria at any point in current pregnancy
- previous infant w/ invasive GBS disease
- unknown GBS status at onset of labor
tx: PCN G or clindamycin/vancomycin if true PCN allergy
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Genetics, Conception, Fetal Development & Reproductive Technology (1)31
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Physiologic Aspects of Antepartum Care (2)33
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Psychosocial Adaption in Pregnancy, Antepartum Testing, & Fetal Monitoring35
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Normal Newborn45
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Intapartum Assessment & Interventions29
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Pain Management, Postpartum Physiological Assessments & Transition to Parenthood43
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High Risk AP Pregestational12
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High Risk Newborn18
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Prelabor and Gestational Onset19
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Perinatal Loss8
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Postpartum Mood Disorders9
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Women's Health and Contraception28
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Alterations in Women's Health and STIs44
