Background
The rising rate of preterm birth (the birth of an infant before 37 completed weeks of pregnancy) is a serious, complex and unresolved public health problem for which there are very few known preventative interventions [
1]. Preterm birth is a leading cause of perinatal mortality, serious neonatal morbidity and moderate to severe childhood disability [
2‐
5]. Although preterm births currently comprise 10% of all births internationally [
6], they contribute to more than two-thirds of perinatal mortality (fetal loss and neonatal death) [
4]. At present there is an incomplete understanding of the mechanisms responsible for spontaneous preterm labour however multiple aetiologies and/or pathological processes are closely associated [
3,
5].
Idiopathic preterm birth correlates strongly with poverty and lower socio-economic status [
7]. Pregnant adolescents are more likely to come from socio-economically disadvantaged backgrounds [
8,
9]. Maternal age of 17 years or less is considered an independent risk factor for preterm birth [
10‐
14]; whether older teenagers 18–19 years of age are at increased risk of preterm birth is contested [
15‐
17]. The effects of social deprivation on pregnant adolescents are cumulative and multifactorial; they directly affect perinatal outcomes including preterm birth [
7]. These include smoking, alcohol and illicit drug use [
8,
18,
19], family violence and/or intimate partner violence [
20‐
22], social isolation [
23,
24], mental health issues including depression [
8,
25,
26], poor nutrition and inadequate weight gain during pregnancy [
25], genito-urinary infection [
27,
28], and severe psychosocial stressors including low income, unemployment and housing issues [
29] or homelessness [
30]. These effects are compounded as teenage women tend to book for pregnancy care at a later gestation, attend fewer appointments or attend no antenatal care at all [
31,
32]. Both non-attendance and under-attendance of antenatal care are independently associated with poor perinatal outcomes including preterm birth [
15,
32].
Improving adolescent health requires improving the factors that make up young people’s daily lives by addressing the risks and perhaps more importantly strengthening protective factors and resilience [
33]. Targeted interventions to address modifiable risk factors for preterm birth have shown promising results, but more research through randomised controlled trial (RCT) design is required [
34]. Two models of care demonstrate potential to reduce the preterm birth rate for this population; group antenatal care [
34,
35] and young women’s clinic [
30]. Whether caseload midwifery improves perinatal outcomes for adolescent women has not been tested [
36].
The trademarked version of group antenatal care, “Centering Pregnancy”, was designed specifically for socio-economically disadvantaged women including adolescents [
37]. In this model groups of 8–12 pregnant women of similar gestation meet regularly for a two-hour facilitated discussion and clinical assessment within the group space [
38]. A 2007 RCT of group antenatal care for young women (14–25 years) found it was associated with lower rates of “inadequate prenatal care” (as determined by the Kotelchuck Index [
39]), and lower rates of preterm birth [
35].
Young Women’s Clinic (YWC) is a model that operates internationally and varies considerably. The key elements include a community clinic setting, multi-disciplinary involvement (including obstetric and allied health presence at the clinic), midwives with additional training, and staff consulting clinical guidelines for working with pregnant adolescents (e.g. sexual health, illicit drug use) [
36]. A 2004 prospective cohort study demonstrated that YWC is associated with higher rates of routine antenatal attendance and lower rates of preterm birth (including preterm prelabour rupture of membranes and threatened preterm labor) for women aged less than 18 years [
30]. These findings should be interpreted with caution however, given that participants were able to self-select either YWC or standard care [
34].
A 2011 systematic review of midwife-led models of care (i.e. team midwifery and caseload midwifery) demonstrated that women who receive this type of maternity care, experience improved maternal and neonatal outcomes without any adverse effects [
40]. Caseload midwifery is provided by a small group of midwives who each provide care for a specific caseload of women on an on-call basis; there is an emphasis on providing a known carer in labour with all women having a named midwife [
41]. While the systematic review included two RCTs of caseload midwifery; the mean age of participants was 27 years (SD 5 years) in both studies [
42,
43], hence the findings are not generalisable to the adolescent population. Midwifery group practice (MGP) is a common form of caseload midwifery in Australia (the terms will be used synonymously in this paper) whereby a small group of midwives provide continuity of care throughout pregnancy, birth and the postnatal period for four to six weeks following birth [
41]. An Australian multi-centre trial of caseload midwifery, the Midwives at New Group practice Options (M@NGO) trial, was conducted from 2009–2011 [
44]. The setting for this feasibility study was one of the sites for the M@NGO trial which included women of ‘all-risk’ status but excluded women aged 17 years or less. The M@NGO trial was not powered to detect a significant difference in preterm birth [
44].
We hypothesised that care through a MGP, which incorporates strategies to address the risk factors associated with preterm birth into the one model of care, could decrease preterm birth in pregnant adolescents. We proposed that improving young women’s access to regular, comprehensive antenatal care [
35,
45‐
50], and increasing their sense of trust and safety with their midwife [
51‐
53], could affect their willingness to accept infection screening and treatment [
30,
54], to disclose high-risk behaviors or circumstances [
30,
55,
56], and to adopt strategies which promote health and minimise harm to themselves and their babies [
57,
58]. Although MGP looked promising as an intervention, we were unsure if pregnant adolescents would agree to be randomised into a study as the literature on pregnant adolescent recruitment is scant; thus a feasibility study was conducted.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
JA participated in the design of the study, conducted recruitment, interpreted data, and drafted the manuscript. HS assisted with data interpretation and has been involved in critical revisions of the manuscript. ST was primarily responsible for the conception and design of the M@NGO trial on which this feasibility study was based; she has been involved in critical revisions of the manuscript. SK participated in the design of the study, and has been involved in critical revisions of the manuscript. All authors read and approved the final manuscript.