Preterm labour and birth

Why this is important

Preterm birth is a cause of significant morbidity for women and babies, and impacts negatively on women and their families, as well as being costly to the NHS. There is good evidence for the use of progesterone to reduce preterm birth, however studies include women with a combination of risk factors for preterm birth, such as a history of preterm birth and a shortened cervix.

There is no evidence for the effectiveness of progesterone in women who do not have a short cervix, but who do have other risk factors for preterm birth. It is therefore difficult to decide if progesterone should be recommended for women, and also whether measuring the cervical length to guide treatment is necessary.

Why this is important

Preterm birth is a cause of significant morbidity for women and babies, and impacts negatively on women and their families, as well as being costly to the NHS. There is good evidence for the use of progesterone to reduce preterm birth, however studies include people with a combination of risk factors for preterm birth, such as a history of preterm birth and a shortened cervix.

There is a lack of evidence for the effectiveness of progesterone in women with a cervical length of 25 mm or less, but without other risk factors for preterm birth. It is therefore difficult to decide if progesterone should be recommended for women, and consequently whether measuring the cervix to guide treatment is necessary for women with no other risk factors.

Why this is important

Preterm birth is a cause of significant morbidity for women and babies, and impacts negatively on women and their families, as well as being costly to the NHS. There is good evidence for the use of progesterone to reduce preterm birth, however studies do not define the optimal gestational age that this treatment should be started and stopped, and it is therefore difficult to recommend when it should start and the optimal duration of treatment.

Why this is important

Preterm birth causes significant neonatal morbidity and mortality, as well as long-term disability. Therefore strategies for preventing preterm birth are important. There are recognised risk factors for preterm birth, and so interventions can be offered to women with these risk factors. Both prophylactic cervical cerclage and prophylactic vaginal progesterone are effective in preventing preterm birth in women with a short cervix and a history of preterm birth, but there is limited evidence on which is more effective, and the relative risks and benefits (including costs) of each. More randomised research is needed to compare the relative effectiveness of prophylactic cervical cerclage and prophylactic vaginal progesterone in improving both neonatal and maternal outcomes. This will help women and healthcare professionals to make an informed decision about which is the most effective prophylactic option.

Why this is important

Identifying infection in women with P‑PROM is needed to provide best practice care. Early diagnosis of infection allows consideration of therapeutic strategies (including antibiotics and/or early birth). Effective treatment of infection is particularly important given that sepsis is a common direct cause of maternal death. There is currently limited evidence that serial C‑reactive protein testing might be useful, but the committee is aware that this strategy is in common practice.

Evidence from diagnostic studies is needed about the accuracy of serial C‑reactive protein testing for identifying chorioamnionitis, which is one of the most common and serious infective complications of P‑PROM.

Why this is important

There is some evidence from randomised studies that emergency cerclage might be effective in improving neonatal outcomes in women with a dilated cervix and exposed, intact fetal membranes. However, there is uncertainty about the magnitude of this effect. The full consequences of this strategy and the subgroups of women at risk of preterm labour who might particularly benefit are not known. A randomised controlled trial would best address this question, but a national registry of the most critical outcomes (neonatal mortality and morbidity, maternal morbidity) could also be considered for women who did not want to participate in a randomised trial but who opt for 'rescue' cerclage.

Why this is important

There is evidence from randomised studies that magnesium sulfate has neuroprotective properties for the baby when given to women who will deliver preterm up to 34+0 weeks of pregnancy. However, there is uncertainty about the best method of administering magnesium sulfate for this purpose, with different studies using different strategies. There are significant advantages for the woman and for reducing healthcare costs if a bolus is as effective as a bolus plus infusion, because magnesium sulfate has side effects for the woman, and more monitoring is needed for infusion, with additional associated healthcare costs. A randomised controlled trial would best address this question by assessing the effects of each method on neonatal and maternal outcomes.