Case Study Reports: Prolonged Pregnancy

PROLONGED PREGNANCY

History

A 23-year-old primigravid woman is seen by the midwife in the antenatal clinic at 41 weeks’ gestation. She had an ultrasound scan at 12 weeks that was consistent with her menstrual dates. At 28 weeks she developed pelvic pain and a diagnosis of symphysio- pelvic dysfunction (SPD) was made. She has had regular physiotherapy and needs to use a stick to walk on most days. She has been otherwise well in the pregnancy and all blood tests have been within the normal range. She reports normal fetal movements. There is no reported vaginal loss.

Examination

Her blood pressure is 126/72 mmHg. The symphysiofundal height is 40 cm and the pre- sentation is cephalic, 2/5 palpable. Subjectively the liquor volume feels normal.

You note that she appears unhappy, and on questioning she says that she is just very uncomfortable as a result of the SPD.

Question

·              Explain the appropriate management for this woman from now.

Answer:

The estimated due date is only a guide and women are expected to deliver between 3 weeks before and 2 weeks after this date. Twenty-five per cent of women will not have delivered by 41 weeks (18 per cent by 42 weeks). As this woman is 41 weeks, plans should be made for induction of labour if spontaneous labour does not occur in the next few days.

Cervical sweep

A cervical sweep involves a vaginal examination to assess the cervix, and insertion of the finger through the cervical os if possible and then sweeping it around the inside of the lower uterus, trying to separate the membranes from the cervix. Such membrane sweep- ing decreases the rate of prolonged pregnancy (>42 weeks).

Induction of labour

Admission should be planned for induction of labour between 41 and 42 weeks, assuming spontaneous labour has not occurred. This gestation is used because stillbirth increases with gestational age above 37 weeks. There is a similar increase in neonatal mortality.

Although the woman is in some discomfort, early induction should be avoided as far as possible, as success of induction increases with gestation.

Method of induction of labour

Prostaglandins should be used for induction of labour with insertion of prostaglandin gel (or pessary) into the posterior fornix of the vagina. The fetus should be monitored by cardiotocograph for 20 min before and after as prostaglandins may cause uterine hyper- stimulation and fetal distress.

If spontaneous contractions have not started or membranes ruptured after 6 h, then the prostaglandin should be repeated. If contractions have commenced (regardless of whether membranes are intact) then vaginal examination should be repeated every 4 h.

If membrane rupture has occurred but contractions have not started after 2–4 h, then an oxytocin infusion would normally be commenced. Subsequent management is as for normal labour.

Expectant management beyond 42 weeks

If the woman declines induction of labour by 42 weeks, fetal wellbeing should be assessed with ultrasound for fetal growth and liquor volume. Fetal movements should be moni- tored, with induction regularly reconsidered.