Parturition - Stages of labor Flashcards Preview

OBGYN - 3. OB normal > Parturition - Stages of labor > Flashcards

Flashcards in Parturition - Stages of labor Deck (17)
Loading flashcards...
1
Q

Stages, end and beginning

A
  • First stage
    • Starts with painful regular contractions (5 minutes apart for 1 hour, i.e. ≥ 12 contractions per hour)
    • Ends with cervical dilatation
  • Second stage
    • Starts with 10 cm cervical dilatation
    • Ends with fetal delivery
  • Third stage
    • Delivery of placenta and membranes
2
Q

Labor initiation is heralded by ____

A

Bloody show

3
Q

Contractions are painful possible because of:

A
  1. Hypoxia to myometrium
  2. Compression of the nerve ganglia
  3. Cervical stretching during dilatation
  4. Stretching of peritoneum overlying fundus
4
Q

What is the Ferguson reflex?

A

Mechanical stretching of the cervix enhances uterine activity

5
Q

T/F. The myometrium relaxes to its original length after contraction

A

False

6
Q

Explain the formation of physiologic retraction ring

A
  • The upper uterine segment becomes progressively thickened throughout thr 1st and 2nd stage of labor
  • The lower segment is thinning
    • Concommitant occurence causes physiologic retraction ring formation
7
Q

Explanation for the formation of pathological retraction ring (of Bandl)

A

Happens when the thinning of the lower uterine segment is extreme as in obstructed labor, the ring is prominent leading to formation of pathologic retraction ring

8
Q

Most important force in fetal expulsion

A

Pushing or maternal intraabdominal pressure

9
Q

Forces that cause cervical dilatation

A
  • Centrifugal pull exerted on the cervix
  • Hydrostatic action of the amniotic sac or presenting part (if membranes are present) dilates the cervical canal like a wedge
10
Q

The leading portion of fluid and amniotic sac located in front of the presenting part that is formed during the process of cervical effacement and dilatation

A

Forebag

11
Q

The pattern of cervical dilatation during preparatory and dilatational divisions of normal labor

A

Sigmoid

12
Q

Description of uterine contractions during the 2nd stage of labor

A

UC averages from 30-90 seconds, averaging around 1 minute, interval between contractions is around 1 minute or less

13
Q

____ curve is formed when the station of the fetal head is plotted as a function of labor duration

A

Hyperbolic

14
Q

Fetal and maternal structures used as references in measuring station

A

Fetal biparietal diameter in relation to a line drawn between maternal ischial spines

15
Q

Phase in the Friedman curve where increased rates of descent are observed in nulliparas

A

Phase of maximum slope

16
Q

Signs of placental separation (in order)

A
  1. Uterus becomes globilar and firmer (Calkin’s sign)
  2. Sudden gush of blood
  3. Uterus rises in the abdomen
  4. Lengthening of the cord
17
Q

How does blood ‘escape’ in Schultze vs Duncan mechanism?

A
  • Schultze
    • blood from the placental site pours into the membrane sac and does not escape externally until after extrusion of the placenta
  • Duncan
    • placenta separates first at the periphery and the blood collects between the membranes and the uterine wall and escapes from the vagina
    • Placenta descends sideways, maternal surface appears first