Preterm Birth

Question 1

What is considered early preterm?

Answer 1

33 6/7 weeks or earlier

Question 2

What is considered late preterm?

Answer 2

34 to 36 weeks

Question 3

What is considered early term?

Answer 3

37 to 38 6/7 weeks

Question 4

What is considered full term?

Answer 4

39 to 40 6/7 weeks

Question 5

What is the ‘39-week rule’?

Answer 5

Adverse neonatal sequelae may result from elective delivery prior to 39 weeks

Question 6

What are the fetal sizes by gestational age?

Answer 6

SGA (<10% BW), AGA (10th-90th%), LGA (>90%)

Question 7

What are the common causes of preterm labor?

Answer 7

Uterine distention, maternal-fetal stress, cervical dysfunction, infection

Question 8

What are the risk factors for uterine distention?

Answer 8

Multifetal pregnancy, hydramnios (more than 2L of amniotic fluid)

Question 9

What maternal hormones play a role in preterm labor due to stress?

Answer 9

Corticotropin-releasing hormones causing premature rise in estrogen

Question 10

What are common types of infections that cause preterm labor?

Answer 10

Transplacental, retrograde flow, ascending infection from vagina and cervix

Question 11

What is Preterm Premature Rupture of Membranes (PPROM)?

Answer 11

A condition where the amniotic sac breaks before labor begins, leading to preterm birth.

Question 12

What are the major predisposing factors for PPROM?

Answer 12

Oxidative stress, intrauterine infection, premature cellular senescence

Question 13

How does multifetal pregnancy affect preterm labor?

Answer 13

Uterine distension leads to premature activation of contraction-associated proteins (CAPs)

Question 14

What are lifestyle factors that contribute to preterm birth?

Answer 14

Age, poverty, short stature, extremes of maternal weight, smoking, drug use

Question 15

What genetic factors contribute to preterm birth?

Answer 15

Immunoregulatory genes can potentiate chorioamnionitis and cause recurrent preterm birth

Question 16

What is the most important risk factor for preterm labor?

Answer 16

Prior preterm birth

Question 17

How do short intervals between pregnancies affect preterm birth?

Answer 17

Intervals <18 months increase the likelihood of preterm birth

Question 18

What is the role of progesterone therapy in preventing preterm birth?

Answer 18

Progesterone helps maintain uterine quiescence and prevents early contractions

Question 19

What is the role of cervical cerclage in preventing preterm birth?

Answer 19

It supports the cervix in women with cervical insufficiency or short cervix

Question 20

What is the guideline for corticosteroid use to accelerate fetal lung maturity?

Answer 20

Recommended for women with ruptured membranes between 24-34 weeks

Question 21

What are the key interventions for managing PPROM in pregnancies over 34 weeks?

Answer 21

Plan delivery, group B streptococcal prophylaxis, single corticosteroid course

Question 22

What antimicrobial therapy benefits exist in managing preterm labor?

Answer 22

Fewer women develop chorioamnionitis, fewer newborns develop sepsis

Question 23

What are the risk factors for clinical chorioamnionitis?

Answer 23

Maternal fever, low parity, multiple digital exams, use of internal uterine monitors

Question 24

What are the tocolytic agents used to delay labor?

Answer 24

Beta-adrenergic receptor drugs, magnesium sulfate, prostaglandin inhibitors

Question 25

What are the side effects of beta-adrenergic receptor drugs?

Answer 25

Pulmonary edema, sodium and water retention

Question 26

How is magnesium sulfate used in preterm labor management?

Answer 26

Given as a loading dose of 4g, followed by continuous infusion to delay labor

Question 27

What are calcium channel blockers used for in preterm labor?

Answer 27

Inhibit calcium entry in cells, reduce contractions (e.g., nifedipine)

Question 28

What is the function of fetal fibronectin?

Answer 28

It plays a role in intercellular adhesion during implantation and maintains placental adherence to the uterine wall.

Question 29

What does a positive fetal fibronectin test indicate?

Answer 29

It may indicate impending preterm labor if levels exceed 50 ng/mL in cervico-vaginal secretions.

Question 30

How is cervical length measured and what is considered short?

Answer 30

Cervical length is measured via transvaginal ultrasound; a short cervix is < 3cm.

Question 31

What is the purpose of cervical cerclage?

Answer 31

It is a surgical procedure to prevent premature dilation of the cervix in women at risk of preterm birth.

Question 32

What is the rationale for using corticosteroids in preterm birth management?

Answer 32

Corticosteroids accelerate fetal lung maturity and reduce the risk of respiratory distress syndrome (RDS).

Question 33

What are the symptoms of true preterm labor?

Answer 33

Regular contractions before 37 weeks, associated with cervical change.

Question 34

What is the role of amniocentesis in managing preterm labor?

Answer 34

It can help detect intrauterine infection but is not routinely used in preterm birth management.

Question 35

What is magnesium sulfate used for in preterm labor?

Answer 35

It provides neuroprotection and may reduce the incidence of cerebral palsy in preterm infants.

Question 36

What are the main contributors to preterm labor due to infection?

Answer 36

Bacterial vaginosis, chorioamnionitis, ascending infections from the vagina and cervix.

Question 37

What is the significance of Braxton Hicks contractions?

Answer 37

These are irregular, non-rhythmic contractions that can be mistaken for false labor.

Question 38

What are common medications used as tocolytics?

Answer 38

Magnesium sulfate, beta-adrenergic receptor drugs, prostaglandin inhibitors, calcium channel blockers.

Question 39

What lifestyle factors increase the risk of preterm birth?

Answer 39

Smoking, drug use, poor nutrition, low maternal weight gain, and physical activity extremes.

Question 40

What is the recommended management for preterm premature rupture of membranes (PPROM) at 34 weeks?

Answer 40

Delivery is recommended, along with group B streptococcal prophylaxis and corticosteroids.

Question 41

What genetic factors are linked to preterm birth?

Answer 41

Genetic mutations affecting collagen, elastic fibers, and immunoregulatory genes are implicated.

Question 42

What is a rescue cerclage?

Answer 42

A rescue cerclage is placed when cervical incompetence is identified in women with threatened preterm labor.

Question 43

What role do antimicrobials play in preterm labor?

Answer 43

Antimicrobials can prolong pregnancy by reducing infection-related preterm labor but should not be used routinely in women without infection.

Question 44

Oxytocin receptor antagonist in myometrium and decidua

Answer 44

Atosiban

Question 45

Prostaglandin inhibitor

Answer 45

Indomethacin 50-100 mg LD, 25-50 mg PO q8 for 1-2days

Question 46

Low birthweight refers to neonates weighing

Answer 46

1500 to 2500 g

Question 47

extremely low birthweight refers to

Answer 47

<1000 g

Question 48

lower limit o etal maturation compatible with extrauterine survival

Answer 48

threshold o viabil- ity