Does model of maternity care make a difference to birth outcomes for young women? A retrospective cohort study

https://doi.org/10.1016/j.ijnurstu.2015.04.011Get rights and content

Abstract

Background

Adolescent pregnancy is associated with adverse outcomes including preterm birth, admission to the neonatal intensive care unit, low birth weight infants, and artificial feeding.

Objective

To determine if caseload midwifery or young women's clinic are associated with improved perinatal outcomes when compared to standard care.

Design

A retrospective cohort study.

Setting

A tertiary Australian hospital where routine maternity care is delivered alongside two community-based maternity care models specifically for young women aged 21 years or less: caseload midwifery (known midwife) and young women's clinic (rostered midwife).

Participants

All pregnant women aged 21 years or less, with a singleton pregnancy, who attended a minimum of two antenatal visits, and who birthed a baby (without congenital abnormality) at the study hospital during May 2008 to December 2012.

Methods

Caseload midwifery and young women's clinic were each compared to standard maternity care, but not with each other, for four primary outcomes: preterm birth (<37 weeks gestation), low birth weight infants (<2500 g), neonatal intensive care unit admission, and breastfeeding initiation. Two analyses were performed on the primary outcomes to examine potential associations between maternity care type and perinatal outcomes: intention-to-treat (model of care at booking) and treatment-received (model of care on admission for labour/birth).

Results

1908 births were analysed by intention-to-treat and treatment-received analyses. Young women allocated to caseload care at booking, compared to standard care, were less likely to have a preterm birth (adjusted odds ratio 0.59 (0.38–0.90, p = 0.014)) or a neonatal intensive care unit admission adjusted odds ratio 0.42 (0.22–0.82, p = 0.010). Rates of low birth weight infants and breastfeeding initiation were similar between caseload and standard care participants.

Participants allocated to young women's clinic at booking, compared to standard care, were less likely to have a low birth weight infant adjusted odds ratio 0.49 (0.24–1.00, p = 0.049), however when analysed by treatment-received, this finding was not significant. There was no difference in the other primary outcomes.

Conclusions

Young women who were allocated to caseload midwifery at booking, and/or were receiving caseload midwifery at the time of admission for birth, were less likely to experience preterm birth and neonatal intensive care unit admission.

Introduction

This cohort study is part of mixed methods evaluation of two models of maternity care that were designed for, and delivered to, young women aged 21 years or less. The participants in this study have been termed ‘young women’. Young adulthood includes the period from 20 to 24 years of age (World Health Organisation, 2004), whereas adolescence is typically defined as the period from 10 to 19 years of age (World Health Organisation, 2014). Research literature on adolescent pregnancy is considered in this paper because it is the most closely related to the participants; however women aged 20–21 years may not have the same predictors for poor perinatal outcomes that adolescents have.

This study was set in a context where women have access to a number of different models of maternity care. A model of maternity care is a ‘complex intervention’; it has a number of ‘active ingredients’ that work together in order to be effective (Medical Research Council, 2008). The ingredients which define a model of maternity care include: who provides the care (doctors, midwives, allied health), whether the providers are known to the woman, where the care occurs (at home, in hospital, community venue), when the care occurs (gestation at booking, frequency and length of visits, after hours contact), and how the care is provided (one-to-one or group visits). Two models of maternity care (caseload midwifery and young women's clinic) were defined and compared to routine care (standard care) for four primary outcomes.

Pregnant adolescents are more likely to come from socio-economically disadvantaged backgrounds (Imamura et al., 2007), which is associated with smoking, alcohol and illicit drug use (van Gelder et al., 2010), social isolation and mental health issues (Ickovics et al., 2011), poor nutrition and inadequate weight gain (Kabir et al., 2008), and psychosocial stressors including low income, unemployment and housing issues (Savitz et al., 2004). These factors directly affect perinatal outcomes (Malabarey et al., 2012). Maternal age less than 18 years is an independent risk factor for preterm birth (Khashan et al., 2010), low birth weight (LBW) infants (de Vienne et al., 2009), intrauterine growth restriction and stillbirth (Khashan et al., 2010), and neonatal mortality (de Vienne et al., 2009).

Modifying the risk and protective factors in young women's daily lives, particularly for those who are socio-economically disadvantaged, can improve health outcomes (Viner et al., 2012). Young women attend specialist programmes more frequently than standard antenatal care (Allen et al., 2012); attendance increases the opportunities for health interventions to occur. There is increasing evidence that ‘adequate’ antenatal care (e.g. minimum five visits) can improve perinatal outcomes (Raatikainen et al., 2005, Vieira et al., 2012). The different types of maternity care referenced in the literature are defined and described below.

Maternity care in Western countries including Australia, Canada, New Zealand (NZ), the United Kingdom (UK) and the United States (US) is typically provided through one-to-one visits with a doctor or midwife. In Canada and the US over 90% of antenatal care is provided by doctors, compared with NZ and the UK where care is generally provided by midwives and is government-funded (public) (Ehiri and Child, 2009). The majority (70%) of Australian women access public maternity care which is provided by hospital-based midwives or obstetricians, and to a lesser extent community-based family physicians; 30% of women access private obstetric care (Department of Health and Ageing, 2008). Ninety-seven percent of women give birth in a hospital delivery suite; while two percent access a birth centre and fewer than one percent give birth at home (Laws and Sullivan, 2009). Public maternity care is often fragmented, with women typically meeting numerous clinicians (Hartz et al., 2012). This is slowly changing in Australia, and elsewhere, as more hospitals are reorganising services to optimise midwifery continuity of care (Hartz et al., 2012).

Caseload midwifery is increasingly common in countries including Australia, Canada, NZ and the UK (Hartz et al., 2012). The primary purpose of caseload midwifery is relationship building whereby women feel supported by a “known, trusted midwife” throughout pregnancy, birth and the postpartum period (Sandall et al., 2013). In Australia, caseload midwifery is characterised by a midwife undertaking responsibility for the continuum of care throughout pregnancy, birth and postpartum, for a caseload of approximately 40 women per annum in low or all-risk models (Hartz et al., 2012). Caseload midwives often work in a midwifery group practice (MGP) of four midwives, who are on-call for labour and birth; and then continue care up to six weeks following birth (Hartz et al., 2012). A feature of the model is that women have 24-hour telephone access to their primary or back-up midwife (Forti et al., 2013).

A 2013 systematic review included 13 trials of midwife-led continuity models of care either team midwifery (n = 10) or caseload midwifery (n = 3); both models aimed to provide known midwives during pregnancy, birth and postpartum (Sandall et al., 2013). While adolescent women were eligible to participate in the three trials of caseload midwifery (Sandall et al., 2013); the mean age of participants ranged from 26 to 31 years. Therefore, the systematic review does not address the suitability and efficacy of caseload midwifery for young women. Access to caseload midwifery has been mostly limited to ‘low risk’ women; indeed two of the three caseload midwifery trials excluded participants deemed to have risk factors. A recently published randomised controlled trial (RCT) demonstrates that caseload midwifery is safe and cost-effective for women of ‘all risk’ (Tracy et al., 2013); participants in this trial however were aged 18 years or older.

In the research setting, group antenatal care was provided within the caseload model for young women; therefore group antenatal care research literature is briefly described here. A Cochrane systematic review of four RCTs of group antenatal care (CenteringPregnancy™) versus standard care reported no significant differences for key clinical outcomes including preterm birth (Catling et al., 2015). However, the largest RCT (n = 1047) reported that women who received the intervention (i.e. group antenatal care) were less likely to experience preterm birth and more likely to initiate breastfeeding (Ickovics et al., 2007). The inclusion of group antenatal care in the caseload model is a potential limitation that will be explored further in this paper.

Young women's clinic describes an antenatal model of care that focuses exclusively on pregnant young women (Allen et al., 2012). Key elements include a community clinic setting, multi-disciplinary involvement at the clinic, with midwives following additional clinical guidelines and accessing specialist training (e.g. sexual health, illicit drug use) (Allen et al., 2012). Two cohort studies report an association between young women's clinic and fewer preterm births for adolescent women (Fleming et al., 2012, Quinlivan and Evans, 2004) and lower adjusted relative risk of LBW infants (Fleming et al., 2012). There are three other published research papers assessing young women's clinic however the results are unreliable as they were small, underpowered retrospective cohort studies, with differences in baseline characteristics that were not controlled for in the analysis (Allen et al., 2012).

There is a paucity of evidence evaluating the specific effects of models of maternity care on perinatal outcomes for young women. The aim of this study was to determine if caseload midwifery or young women's clinic were associated with improved perinatal outcomes when compared to standard care.

Section snippets

Study design

Ethical approval was granted by the University and Hospital Human Research Ethics Committees prior to study commencement. A retrospective comparative cohort study was designed using routinely collected perinatal data from the hospital's electronic database. Three mutually exclusive study groups: (1) standard care, (2) caseload midwifery and (3) young women's clinic were defined at first booking visit and on admission to hospital for labour/birth. The primary outcomes were then analysed by both

Participants

All publicly funded young women (aged 21 years or less) who had given birth to a singleton baby between May 2008 and December 2012 (n = 2214) were considered for inclusion. 1971 women met the inclusion criteria and 243 women were excluded; complete data were available for 1908 participants (see Fig. 1).

Descriptive data

Table 2 shows the baseline characteristics of the participant groups with caseload midwifery and young women's clinic providing care to a significantly higher proportion of women who were younger,

Key results

This cohort study suggests that, compared to standard care, caseload midwifery may benefit young women and their infants. While we showed no differences between young women's clinic and standard care on any of the primary outcomes; the ability to detect differences was limited by the relatively small number of women in this cohort. After controlling for differences in baseline characteristics and known confounders, caseload midwifery was associated with fewer preterm births and fewer admissions

Acknowledgements

Funding. The first author wishes to acknowledge the support of a Golden Casket grant received from the Mater Foundation in 2009 and an Australian Catholic University Postgraduate Award received during 2013–2014. The funders had no role in the conduct of the research. Everyone who contributed significantly to the work met the criteria for authorship. The findings of the preliminary study (2008–2010 data) were presented at The Australian College of Midwives National Conference in October 2011 in

References (42)

  • M.M. van Gelder et al.

    Characteristics of pregnant illicit drug users and associations between cannabis use and perinatal outcome in a population-based study

    J. Alcohol. Drug Depend.

    (2010)
  • C.L. Vieira et al.

    Modifying effect of prenatal care on the association between young maternal age and adverse birth outcomes

    J. Pediatr. Adolesc. Gynecol.

    (2012)
  • R.M. Viner et al.

    Adolescence and the social determinants of health

    Lancet

    (2012)
  • Australian Bureau of Statistics

    An Introduction to Socio-Economic Indexes for Areas (SEIFA)

    (2008)
  • C.J. Catling et al.

    Group versus conventional antenatal care for women

    Cochrane Database Syst. Rev.

    (2015)
  • I.H. Celik et al.

    A common problem for neonatal intensive care units: late preterm infants, a prospective study with term controls in a large perinatal center

    J. Matern. Fetal Neonatal Med.

    (2013)
  • X.K. Chen et al.

    Teenage pregnancy and adverse birth outcomes: a large population based retrospective cohort study

    Int. J. Epidemiol.

    (2007)
  • Department of Health and Ageing

    Improving Maternity Services in Australia: A Discussion Paper from the Australian Government

    (2008)
  • J.E. Ehiri et al.

    Maternal and child health in the Organization for Economic Cooperation and Development (OECD) countries

  • K. Gibbons et al.

    Customised birthweight models: do they increase identification of at-risk infants?

    J. Paediatr. Child Health

    (2013)
  • K. Guilliland et al.

    The Midwifery Partnership a Model for Practice

    (1995)
  • Cited by (29)

    • Midwifery continuity of care for women with complex pregnancies in Australia: An integrative review

      2023, Women and Birth
      Citation Excerpt :

      Research shows that MCoC provides benefits for specific population groups including young women [8] and Aboriginal and Torres Strait Islander women [9], vulnerable to poorer childbearing outcomes and experiences in their maternity care [10]. Allen et al. [8] found that young women were more likely to attend antenatal care visits throughout pregnancy in a MCoC model than other models and to disclose personal and health issues. The authors highlighted multiple positive mental and physical health benefits of early, prolonged and trusting midwife-woman relationships on perinatal outcomes for women and their babies [8].

    • A scoping review of evidence comparing models of maternity care in Australia

      2021, Midwifery
      Citation Excerpt :

      One cross-sectional study compared the outcomes of public midwifery continuity care with standard public and private obstetric care (Tracy et al., 2014). Public midwifery continuity models evaluated in the included studies were caseload midwifery models (where there is a named primary midwife and continuity of carer) in five studies (Allen et al., 2015; Tracy et al., 2013; Tracy et al., 2014; Forster et al., 2016; McLachlan et al., 2012; Wong et al., 2015) and team midwifery models (which do not typically provide continuity of carer) in three studies (Biró et al., 2003, 2000; Homer et al., 2002, 2001; Waldenström et al., 2000). In 4 studies, public midwifery continuity care was provided at home or community venues by public caseload or team midwives during antenatal and postnatal period and intrapartum care was provided at a public hospital under the supervision of registered midwives designated for each pregnant woman (Allen et al., 2015; Homer et al., 2002, 2001; Tracy et al., 2013; Wong et al., 2015).

    View all citing articles on Scopus
    View full text