Signs of Labor

1
Signs of Labor

• regular, persistent contractions (vs. Braxton
  Hicks contractions) due to oxytocin release from
  pituitary
• loss of mucus plug (cervical dilation)
• rupture of amniotic membranes
• procession through stages 1, 2 and 3

2
Labor

• What induces labor?
• Possible role of fetal adrenal gland
• Stress cortisol release from fetal adrenal
  placenta releases prostaglandins uterine
  contractions
• Contractions oxytocin release from pituitary

3
Stage 1

• longest (8 to 12 hours for first delivery)
• involves effacement and dilation of cervix
• caused by hormonal changes and force of
  myometrial contractions
• as muscles of uterus shorten, pressure is applied
  to baby

4
Stage 1

• 10 cm full dilation
• effacement ranges from 0 - 100 (thinned to the
  point of disappearing)
• transitional phase is often difficult

5
Stage 2

• fetal membranes often break at this point
• mother feels urge to bear down
• lasts from 1 to 2 hours often painful
• mother pushes, adding force of abdominal muscles
  to that caused by uterine muscles

6
Stage 2

• baby moves toward vaginal opening
• crowning occurs when head is visible
• episiotomy may be performed (80)
• after head is born, only a few pushes are
  required for rest of body to exit

7
Stage 3

• once baby is delivered, uterine cavity shrinks
• placenta detaches
• uterine contractions force placenta out within 15
  minutes
• uterine massage can facilitate placenta delivery

8
Medicalization of birthingEpisiotomies

• estimated that rate should not be above 30
• many performed without a womans consent
• fetal monitoring

9
Medicalization of birthing cesarean sections

• rate from 1975-2000 20
• prior to 1970s, rate was 5
• defensive medicine?

10
C-sections

• necessary when baby is in breech position or
  fetal distress is indicated
• risks fetal injury, maternal blood loss,
  infection, blood clots from bed rest

11
Medicalization, contd. induction of labor

• occurs in 10-15 of all hospital deliveries
• involves prostaglandins applied to cervix and/or
  infusion of pitocin
• often causes more intense, painful contractions

12
Induction

• increased risk for use of pain medication,
  episiotomy, operative vaginal delivery, c-section
• fetal risks suffocation, physical injury

13
Midwifery

• alternative care givers who offer a less invasive
  pregnancy experience
• certified nurse midwives attend graduate
  programs usually practice in conjunction with
  univ. or med. school
• licensed nurse-midwives
• not nurses practice in private homes or hospital
  birthing centers
• trained through formal schooling and
  apprenticeships
• must pass state board exams (avail. in 17 states)

14
Midwifery, contd.

• lay midwives
• trained through schooling and apprenticeships
• practice in states without licensing
  opportunities
• cant charge fees in some states
• deliveries with midwives
• less medication, fewer interventions required
• no diff. in duration of labor, perineal lesions,
  maternal blood loss
• no diff. in birthweight, gestational age
• vaginal birth rates higher

15
Lactation

• pregnancy hormones caused growth of breasts
• prior to birth, glands produce colostrum
• after birth, prolactin stimulates milk production
• when infant suckles, letdown reflex occurs

16
Let-down reflex

• sensory receptors in nipples stimulated
• nerve impulse travels to brain
• causes pituitary to release hormones oxytocin
  prolactin
• oxytocin causes myoepithelial cells surrounding
  alveoli to contract

17
Let-down reflex

• prolactin causes milk synthesis
• can be interfered with by stressors (blood vessel
  constriction)
• can become conditioned reflex
• prolactin causes shutdown of reproductive system

18
Benefits of breastfeeding for infant

• Colostrum
• produced 2-5 days postpartum
• high in protein low in fat, carbs
• contains intact cells (macrophages, lymphocytes)
• antibodies (nonspecific IgAs)
• Mature milk
• water, protein, fat, lactose
• vitamins, minerals, salts, hormones

19
Breastmilk vs. formula

• Cows milk-based formula has 3X greater protein
  levels
• primary proteins
• in formula casein (causes curdling)
• in breastmilk whey (easily digested)
• amino acid taurine nearly absent in cows milk
  (now supplemented)

20
Breastmilk vs. formula

• same levels of fat (50) but types differ
• breastmilk has more cholesterol (protective?)
• lipase present in breastmilk
• sucrose added to formula to match high levels of
  sugar (lactose) in breast milk
• bifidus factor present in higher levels in breast
  milk (promotes growth of good bacteria)

21
Breastmilk vs. formula

• lactose promotes calcium absorption
• both may contain environmental contaminants
• viruses (HepB, HIV) can be transmitted thru
  breastmilk