Preterm delivery

Question 1

What is preterm delivery?

Answer 1

Delivery between 24 and 37 weeks gestation.

Question 2

When are the neonatal risks greater?

Answer 2

Before 34 weeks

Question 3

How common is preterm delivery?

Answer 3

It occurs In 5-8% of pregnancies. A further 6% of deliveries present preterm contractions but deliver at term

Question 4

What can cause preterm delivery?

Answer 4

It can be spontaneous labour or, usually at later gestations, can be iatrogenic (PE)

Question 5

What are some acute neonatal complications of preterm delivery?

Answer 5

NICU, perinatal mortality, cerebral palsy

Question 6

What are some long-term neonatal complications of preterm delivery?

Answer 6

Chronic lung disease, blindness and minor disability is common.

Question 7

What are some maternal complications of preterm delivery?

Answer 7

Infection, particularly endometritis. C section is more commonly used.

Question 8

What are some risk factors for spontaneous preterm labour?

Answer 8

Previous preterm delivery; lower socioeconomic class, extremes of maternal age, short inter-pregnancy interval, maternal medical disease, PE, IUGR, male fetal gender, high Hb, STIs, previous cervical surgery, multiple pregnancy, uterine abnormalities, UTI, congenital fetal abnormalities, antepartum haemorrhage

Question 9

What are the mechanisms of preterm labour?

Answer 9

In general: [1] too much in the uterus (twins); [2] the foetus wants to get out (IUGR, PE, infection); [3] the uterus can’t hold the baby (uterine abnormalities); [4] the cervix can’t hold it in anymore (cervical incompetence); [5] infection weakens the cervix/uterus (STI, UTI)

Question 10

How do you investigations predict preterm delivery?

Answer 10

Cervical length of transvaginal sonography (TVS) is both sensitive and specific. Prediction is not the same as prevention though, remember!

Question 11

How do you prevent preterm labour?

Answer 11

Cervical cerclage (sutures to keep it closed); progesterone supplementation; treatment of polyhydramnios; treat underlying medical conditions

Question 12

What is cervical cerclage and when is it performed?

Answer 12

The insertion of one or more sutures in the cervix to strengthen it and keep it closed. This is usually prepregnancy and can be laparoscopic.

Question 13

How does progesterone supplementation take place?

Answer 13

Suppositories from early pregnancy reduce the risk of preterm labour in women at high risk.

Question 14

What antibiotic increases the risk of preterm labour?

Answer 14

Metronidazole

Question 15

What are the clinical features of preterm labour?

Answer 15

Typically, women present with painful contractions. In over half of such women, however, contractions will stop spontaneously. Antepartum haemorrhage and fluid loss are common: the latter suggests ruptured membranes

Question 16

What would you find on examination in preterm labour?

Answer 16

Fever may occur. Check lie and presentation of fetus with abdominal exam. Digital vaginal examination is performed unless the membranes have ruptured. An effaced or dilated cervix confirms the diagnosis

Question 17

What investigations are performed for preterm delivery?

Answer 17

CTG to assess fetal state; fetal fibronectin (negative result means preterm delivery is unlikely); TVS of cervical length is also predictive; look for infection (CRP and swabs)

Question 18

How do you manage preterm labour?

Answer 18

Steroids and tocolysis; detection and prevention of infection; mode of delivery

Question 19

Why are steroids administered in preterm labour?

Answer 19

They reduce perinatal morbidity and mortality by promoting pulmonary maturation

Question 20

Why are tocolytics administered in preterm labour?

Answer 20

To allow 24hrs for steroids to work or to allow in utero transfer to a unit with neonatal intensive care facilities. They delay rather than stopping preterm labour.

Question 21

Give two examples of tocolytics that could be administered in preterm labour?

Answer 21

Nifedipine or atosiban

Question 22

How do you treat chorioamnionitis?

Answer 22

IV antibiotics and immediate delivery, whatever the gestation

Question 23

Does preterm labour alter the mode of delivery?

Answer 23

No. Vaginal delivery reduces the incidence of respiratory distress syndrome in the neonate and C section is only used for usual obstetric indications

Question 24

Is breech presentation more common in preterm delivery?

Answer 24

Yes, it usually requires a C section

Question 25

Should cord clamping be altered in preterm delivery?

Answer 25

Unless immediate neonatal resuscitation is required, the cord should not be clamped for 45 seconds, to reduce neonatal morbidity.

Question 26

When should antibiotics be given?

Answer 26

They are recommended in women in preterm labour, as opposed to threatening preterm labour, because of the increased risk and morbidity.

Question 27

What is preterm prelabour rupture of the membranes?

Answer 27

The membranes rupture before labour at <37 weeks.

Question 28

What are the complications of preterm prelabour rupture of the membranes?

Answer 28

Preterm delivery; infection (chorioamnionitis) or cord (funsitis); prolapse of the umbilical cord; pulmonary hypoplasia

Question 29

How common is preterm labour after preterm prelabour rupture of the membranes?

Answer 29

It follows within 48 hours in >50% of cases.

Question 30

Is infection usually before or after the preterm prelabour membrane rupture?

Answer 30

It can occur before (and be the cause of) the rupture or it can follow the rupture

Question 31

What are the clinical features of preterm prelabour of the membranes?

Answer 31

A gush of clear fluid is normal, followed by further leaking

Question 32

What would you find on examination after preterm prelabour of the membranes?

Answer 32

A pool of fluid in the posterior fornix on speculum examination is diagnostic, but this is not invariable. Digital examination is best avoided, although it is performed o exclude cord prolapse if the presentation is not cephalic.

Question 33

What are the clinical features of chorioamnionitis?

Answer 33

Contractions or abdominal pain, fever, tachycardia, uterine tenderness and coloured or offensive liquor, although clinical signs often appear late.

Question 34

What investigations would you perform in preterm prelabour rupture of the membranes?

Answer 34

US to assess liquor volume; blood tests to look for infection (high vaginal swab, FBC, CRP), CTG to assess fetal well-being

Question 35

How do you manage preterm prelabour rupture of the membranes?

Answer 35

The woman is admitted and given steroids, close maternal (infection) and fetal surveillance is performed, induction after 36 weeks

Question 36

Would you give prophylactic antibiotics for preterm prelabour rupture of the membranes?

Answer 36

Erythromycin is usually given prophylactically

Question 37

What antibiotics would you not give in preterm prelabour rupture of the membranes?

Answer 37

Co-amoxiclav is contra-indicated