Premature Labour

Question 1

Rupture of membranes (ROM)

Answer 1

The amniotic sac has ruptured

Question 2

Spontaneous rupture of membranes (SROM)

Answer 2

The amniotic sac has ruptured spontaneously

Question 3

Preterm prelabour rupture of membranes (P‑PROM)

Answer 3

The amniotic sac has ruptured before the onset of labour and before 37 weeks gestation (preterm)

Question 4

Prolonged rupture of membranes (also PROM)

Answer 4

The amniotic sac ruptures more than 18 hours before delivery

Question 5

Prematurity

Answer 5

Prematurity is defined as birth before 37 weeks gestation

Question 6

When are babies non viable

Answer 6

Below 23 weeks gestation.

Generally, from 23 to 24 weeks, resuscitation is not considered in babies that do not show signs of life.

Question 7

Classification of prematurity

Answer 7

Under 28 weeks: extreme preterm

28 – 32 weeks: very preterm

32 – 37 weeks: moderate to late preterm

Question 8

Prophylaxis of Preterm Labour

Answer 8

Vaginal progesterone

Cervical cerclage

Question 9

Vaginal Progesterone

Answer 9

Progesterone maintains the pregnancy and prevents labour by decreasing activity of the myometrium and prevents the cervix remodelling in preparation for delivery

Question 10

Who is offered vaginal progesterone

Answer 10

Women with a cervical length less than 25mm on vaginal ultrasound between 16 and 24 weeks gestation

Question 11

Cervical Cerclage

Answer 11

Involves putting a stitch in the cervix to add support and keep it closed.

This involves a spinal or general anaesthetic.

The stitch is removed when the woman goes into labour or reaches term

Question 12

Who is offered cervical cerclage

Answer 12

Women with a cervical length less than 25mm on vaginal ultrasound between 16 and 24 weeks gestation, who have had a previous premature birth or cervical trauma (e.g. colposcopy and cone biopsy)

Question 13

Rescue cervical cerclage

Answer 13

Offered between 16 and 27 + 6 weeks when there is cervical dilatation without rupture of membranes, to prevent progression and premature delivery

Question 14

How to diagnose preterm prelabour rupture of membranes

Answer 14

Speculum examination revealing pooling of amniotic fluid in the vagina

Question 15

When there is doubt about a preterm prelabour rupture of membranes on speculum

Answer 15

Insulin-like growth factor-binding protein-1 (IGFBP-1) - tested on vaginal fluid if there is doubt about rupture of membranes

Placental alpha-microglobin-1 (PAMG-1) is a similar alternative to IGFBP-1

Question 16

Management of preterm prelabour rupture of membranes

Answer 16

Prophylactic antibiotics given to prevent the development of chorioamnionitis.

Induction of labour may be offered from 34 weeks to initiate the onset of labour

Question 17

Which prophylactic antibiotics are given in preterm prelabour rupture of membranes

Answer 17

Erythromycin 250mg qds for ten days, or until labour is established if within ten days

Question 18

Preterm Labour with Intact Membranes

Answer 18

Preterm labour with intact membranes involves regular painful contraction and cervical dilatation, without rupture of the amniotic sac

Question 19

How to diagnose preterm labour with intact membranes

Answer 19

Speculum examination - cervical dilatation.

Less than 30 weeks gestation - clinical assessment alone enough to offer management of preterm labour

More than 30 weeks gestation - a transvaginal ultrasound to assess the cervical length.

• cervical length less than 15mm - management of preterm labour offered.
• cervical length of more than 15mm - preterm labour is unlikely

Fetal fibronectin is an alternative test to vaginal ultrasound.

Question 20

Fetal fibronectin

Answer 20

Fetal fibronectin - “glue” between the chorion and the uterus, and is found in the vagina during labour.

A result of less than 50 ng/ml is considered negative, and indicates that preterm labour is unlikely

Question 21

Management of preterm labour

Answer 21

Fetal monitoring (CTG or intermittent auscultation)

Tocolysis with nifedipine: calcium channel blocker that suppresses labour

Maternal corticosteroids: can be offered before 35 weeks gestation to stimulate surfactant production

IV magnesium sulphate: can be given before 34 weeks gestation and helps protect the baby’s brain

Delayed cord clamping or cord milking: can increase the circulating blood volume and haemoglobin in the baby at birth

Question 22

Tocolysis

Answer 22

Nifedipine to stop uterine contractions

Used between 24 and 33 + 6 weeks

Atosiban - oxytocin receptor antagonist that can be used as an alternative

Question 23

Antenatal Steroids

Answer 23

Used in women with suspected preterm labour of babies less than 36 weeks gestation

Two doses of intramuscular betamethasone, 24 hours apart.

Question 24

Magnesium Sulfate

Answer 24

IV magnesium sulfate protect the fetal brain during premature delivery.

Reduces the risk and severity of cerebral palsy

Given within 24 hours of delivery of preterm babies of less than 34 weeks gestation.

It is given as a bolus, followed by an infusion for up to 24 hours or until birth

Question 25

Monitoring for magnesium sulphate

Answer 25

Monitor for magnesium toxicity at least 4 hourly

Close monitoring of observations + tendon reflexes (usually patella reflex).

Question 26

Signs of magnesium toxicity

Answer 26

Reduced RR
Reduced BP
Absent reflexes