preterm labor, preterm rupture

Question 1

preterm labor - risk factors (strongest?)

Answer 1

1. premature rupture membranes
2. multiple gestation
3. previous history of preterm labor (strongest)
4. placental abruption
5. maternal factors (uterine anatomical abn, infections, preeclampsia, intraabdominal surgery)
6. IUGR
7. short cervix length
8. cervical srgery (cold knife conization)
9. cigarette use

Question 2

maternal factors that are associated with preterm labor

Answer 2

1. uterine anatomical abnormalities (bicornate uterus)
2. infections (chorioamnionitis)
3. preeclampsia
4. intrabdominal surgery

Question 3

preterm labor - presentation

Answer 3

1. contractions (abd pain, lower back pain or pelvic pain)

2. dilation of cervix

Question 4

how can preterm labor be stopped (and how)

Answer 4

with tocolytics

slow the progresion of cervical dilation by decreasing uterine contraction

Question 5

preterm labor evaluation

Answer 5

the fetus should be evaluated for:

1. weight
2. gestational age
3. presenting part (cephalic vs breech)

Question 6

circumstances in which preterm labor should not be stopped with tocolytics and delivery should occur

Answer 6

1. maternal severe hypertension (preeclampsia/eclampsia)
2. matenal cardiac disease
3. maternal cervical dilation more than 4 cm
4. maternal hemorrhage (abruptio placenta, DIC)
5. fetal death
6. chorioamnionitis
7. 34-37 EGA + more than 2.500 grams.

Question 7

preterm labor - corticosteroids (purpose, time)

Answer 7

• betamethasone –> to mature fetus’ lungs
• effects begin within 24h, peak at 48h, persist for 7d
• they will decrease the risk of resp distress syndrome and neonatal mortality (increase surfactant)

Question 8

preterm: corticosteroids vs tocolytics

Answer 8

when steroids are administrated, a tocolytic should follow to allow time for steroid to wotk

Question 9

tocolytics - drugs

Answer 9

1. calcium channel blocker

2. terbutaline (b-adrenergic –> myometrial relaxation)

Question 10

tocolytics - terbutaline mechanism of action and SE

Answer 10

b-adrenergic –> myometrial relaxation

increase maternal HR –> palpitations + hypotension

Question 11

preterm labor management regarding time

Answer 11

• less than 32 wks: betamethasone, tocolytics, MgSO2, penicillin
• 32 - 33,6: betamethasone + tocolytics + penicillin
• 34 and more: +/- betamethasone, penicillin
  MgSO4: fetal neuroprotextion
  Penicillin if strep + or unknown

Question 12

preterm labor - definition

Answer 12

regular contractions before 37 wks that cause cervical dilation and/or effacement

Question 13

Premature rupture of the membranes presentation

Answer 13

gush of fluid from vagina before 37 weeks

Question 14

premature rupture of the membranes - diagnostic test

Answer 14

sterile speculum examination should confirm the fluid as amniotic fluid:

1. fluid is present in posterior fornix
2. fluid turns nitrazine paper blue
3. when placed on slide and allowed to air dry fluid has ferning pattern

Question 15

Premature rupture of the membranes can happen at …(time) / when it becomes problem

Answer 15

• at any time throughout time

- it becomes the biggest problem when the fetus is preterm or with prolonged rupture of membranes

Question 16

prolonged rupture?

Answer 16

the labor starts more than 18 h before delivery

Question 17

Premature rupture of the membranes leads to:

Answer 17

1. preterm labor
2. cord prolapse
3. placental abruption
4. chorioamniotis

Question 18

management of preterm prelabor rupture of membranes

Answer 18

• 34-37 wks: antibiotic +/- corticosteorids. delivery
• less than 34: signs of infection or fetal compromise:
  NO: antibiotics, corticosteroids, surveillance
  YES: antibiotics, corticosteroids, delivery, magnesium if less than 32

Question 19

1st step in evaluating the risk of preterm labor

Answer 19

transvaginal U/S measurement of cervical length in the 2nd trimester –> short cervical length is a strong predictor for preterm labor

Question 20

Preterm birth prevention

Answer 20

history of preterm labor?
NO –> Transvaginal U/S: If normal cervix then routine prenatal care. If short then vaginal progesterone
YES –> progesterone injection + Transvaginal U/S: if normal cervic then serial transvaginal U/S until 24 wks. If short then Cerclage, serial transvaginal U/S until 24 wks

Question 21

fetal fibronectin

Answer 21

high until 20 weeks, low during the mid-second and 3rd trimester –> increased again at term, when contractions disrupts the decidual-chorionic interface –> elevated level prior to term are used as indicator for increased risk of preterm labor