Q&a attempts to provide balanced answers to those curly-yet-common questions in obstetrics and gynaecology for the broader O&G Magazine readership, including Diplomates, Trainees, medical students and other health professionals.

Q

‘A primigravid woman at 32 weeks gestation presents to the birth suite with painful regular contractions. She has presented twice previously with the same complaint and each time been determined to have a closed, non-effacing cervix, a normal CTG and has been discharged home after 24 hours of observation. At her first presentation at 28 weeks she was given two doses of betamethasone. How should her pregnancy be managed?’

a Threatened preterm labour (TPL) is a serious complication of pregnancy and should be treated according to best practice guidelines.¹ While some women who experience preterm contractions will settle spontaneously, some will continue to experience painful contractions, without cervical changes, for the remainder of their pregnancy. The management of the ‘irritable uterus’ represents a dilemma in management for clinicians.

Any woman presenting with painful regular contractions should be offered adequate analgesia and assessed for imminent delivery. Physical assessment of the mother, including abdominal palpation and cervical assessment via a speculum examination, vaginal examination or a transvaginal ultrasound scan for cervical length (TVCL)² should be undertaken, as well as tests such as fetal fibronectin (fFN) detection to establish the likelihood of delivery.^3,4 Depending on gestation and local facility guidelines, it may be appropriate to consider tocolysis and steroid cover. A number of women will not demonstrate any of the features of labour and a diagnosis of irritable uterus may be entertained.

Irritable uterine activity may commence at any stage during a pregnancy and persist for its entirety or be only a transient experience. Inflammatory conditions, such as subclinical chorioamnionitis, upper genital tract infection and urinary tract infections or pyelonephritis, may be associated with irritable contractions.^5,6 Likewise, gastrointestinal problems, such as gastroenteritis with vomiting and diarrhoea or even significant constipation, may also trigger uterine irritability. Assessment should include investigations for inflammatory causes, genital and cervical culture swabs. Other causes for uterine irritability include subchorionic placental bleeding. Ultrasound scan for fetal growth and well-being and examination of the placenta for evidence of concealed bleeding may be performed in conjunction with TVCL assessment.

Identification and, where possible, treatment of underlying causes of uterine irritability may allow for complete resolution. Admission to the antenatal ward for ongoing observation and assessment is often warranted. Occasionally, contractions thought to be associated with TPL or uterine irritability may be the result of pseudo-labour, a poorly understood variant of conversion disorder, often associated with anxiety and emotional disturbance.⁷

For women experiencing ongoing uterine irritability without any obvious cause, antenatal care can usually proceed in the normal manner. Maintenance tocolysis is not recommended for uterine irritability.^8,9,10,11,12 Not only have studies demonstrated that they are of questionable value in terms of prolonging the pregnancy, but it is also suggested that women with uterine irritability may demonstrate resistance to commonly used tocolytics.¹³ Vaginal progesterone may play a role in prolonging pregnancy to 34 weeks.^14,15,16,17 Further analysis is still required to determine if improvement in neonatal outcomes warrants this intervention for women with irritable uterus.

Uterine irritability is associated with a higher rate of preterm delivery than the general population (although lower than for women with other preterm labour risk factors).¹³ It is possible that a woman with ongoing irritable uterine contractions may develop preterm labour, but fail to recognise it until ‘too late’. Thus the question facing clinicians revolves around how to mitigate these risks.

Administering corticosteroids for fetal lung maturity is a routine part of managing preterm labour. It has been demonstrated that a single course of corticosteroids administered after 27 weeks is as efficacious as multiple ‘rescue’ doses.¹⁸ It could be proposed that all women presenting with contractions after 27 weeks gestation be given corticosteroids at their initial presentation, regardless of cervical assessment or likelihood of imminent delivery, in order to ensure optimal fetal lung maturity.

Infants delivered prior to 37 weeks gestation are at increased risk from group B streptococcal infection and women in preterm labour should receive antibiotic prophylaxis.^1,19 Antibiotic cover needs to be initiated at least hours hours prior to delivery in order to have the full protective effect. The key to management remains careful surveillance.

Many women will self-refer for assessment due to concerns regarding the changing nature of their ‘regular’ uterine irritability, suspected ruptured membranes, bleeding or altered fetal movement patterns. For women with other risk factors for preterm labour, regular TVCL measurement may be necessary and repeat fFN assessment may be warranted.

Our primigravida is almost certainly experiencing an irritable uterus. She was given corticosteroids at her first admission at 28 weeks, and evidence suggests her baby will not benefit from any further doses. Management at this presentation should consist of analgesia and routine assessment, including CTG monitoring. She should have cervical assessment incorporating swabs for fFN, vaginal and endocervical cultures. Cervical dilatation should be checked and urine analysis performed.

If it is determined she is in labour, she will require antibiotics and possibly transfer to an appropriate facility. If the assessment does not suggest imminent delivery, she should have an ultrasound scan arranged, including TVCL. Admission to the antenatal ward may be appropriate and any possible underlying causes of uterine irritability should be identified and treated.

Her ongoing antenatal care should involve careful assessment of uterine activity and causes of uterine irritation should continue to be explored. There is no indication for prophylactic tocolysis; however, vaginal progesterone may be of benefit. Her management should include assessment of any contributing psycho-social factors, in addition to providing reassurance that her concerns are being taken seriously.

Encouragingly, many women with this presentation will continue their pregnancy to term and deliver without complications.