Social inequity in perinatal and maternal health is a well-documented health problem  affecting women the world over. Systematic disparities in health associated with social determinants  are still seen in societies with high levels of social equality. Even in the Nordic countries with their comprehensive public health care and welfare systems, social factors exert a strong influence on both maternal and perinatal birth outcomes [1, 3].
Socially disadvantaged women, as defined by factors such as low levels of education, employment, income, or residence in a deprived area, suffer increased morbidity and mortality during childbirth [1, 4] when compared to women from socially advantaged backgrounds. Their infants have higher perinatal and neonatal morbidity and mortality [3–9] and are more often born preterm [10–13], with lower Apgar scores and birth weight [4, 9, 14–16] and are overrepresented [17, 18] in neonatal units.
The incidence of epidural analgesia [19, 20], use of an upright birth position , caesarean section and other birth interventions have also been suggested as being affected by social inequality, but results on caesarean section are conflicting with some studies finding a higher [22, 23] and others a lower likelihood among disadvantaged women [24–29]. It is unclear whether this inconsistency in findings for caesarean section and epidural is due to differences in the organisation of maternity care services (private/public) [25, 28–30], hospital specialisation level , and the type of lead caregiver (obstetrician/midwife) . It may be noted, though, that the use of birth interventions is more widespread in societies with high levels of hospitalisation and specialisation and where private health services are prevalent [25, 28–31].
It has been argued that disadvantaged pregnant women perceive themselves as having little knowledge and little choice, and that they have considerable faith in medical “experts” , and are more positive towards interventions and use of medical pain relief compared to advantaged women . In this perspective, disparities in the use of intervention, pain relief and birth position are seen to reflect different preferences between the two groups of women. However, Green et al. [35, 36] have contested this perception while Lazarus has argued that insufficient attention is given to how social restraints and conditions impact on women’s expectations and experiences . We find it likely, as argued by de Jorge , that some care options are offered less frequently to disadvantaged women while health professionals tend to offer more positive responses to the wishes and demands of advantaged, confident and articulate women [28, 38]. They may also generally receive a higher level of continuity of care , higher quality care and be prioritised over disadvantaged women .
The complex relationship between social disadvantage and birth outcomes is confounded by the influence of several factors such as stressful life conditions, life style, health behaviours and their accompanying/underlying medical conditions . Despite an overall increased risk of complications, the majority of disadvantaged women enter spontaneous labour at term without having developed maternal or perinatal complications and are thus categorised as being at low risk of intrapartum complications. As population-based studies generally are not able to take into account differences in women’s obstetric risk factors [1, 3–10, 13, 14, 16–18], it is unclear whether social inequality persists among these women.
Obstetric units (OU) have today become the primary setting for birth in most middle- and high-income countries, often with all frontline care being provided by midwives. However, alternative birth settings such as freestanding midwifery units (FMUs) are also offered in several countries, including New Zealand , the United Kingdom , Canada , the United States , Italy , Germany , the Republic of South Africa , Brazil , Norway , in some of which childbirth policies aim to provide women with a choice of birthplace [51, 52].
Generally, FMUs are based on a woman/family-centred philosophy and aim to provide supportive, individualised care and encourage spontaneous, vaginal birth . They provide low-risk women with a choice among different models of intrapartum care. In sparsely populated areas, FMUs offer care closer to home (to low-risk women) , while in low-income countries they may provide women with affordable and accessible care [54, 55].
The primary professional responsibility for care in FMUs is in the hands of midwives. All need for obstetrical, neonatal, and anaesthetic care requires ambulance transfer of the women and /or infant to an OU . As acute perinatal and maternal complications may arise in spite of careful risk assessment of women, safety of FMU care has been a concern and until recently limited evidence has been available .
In 2011 the Birthplace in England Research Programme, an extremely large, prospective cohort study, found no significant differences in perinatal outcome between women intending to give birth in a FMU and women intending to give birth in an OU while the use of medical interventions and medical pain relief were significantly reduced among women receiving care from FMUs . In our own recent study of FMU versus OU care in Denmark, we compared perinatal outcomes for low-risk women intending to give birth in an FMU and low-risk women intending to give birth in an OU. We also found no difference for perinatal outcomes while women in the FMU group had reduced maternal morbidity and fewer birth interventions .
Several studies document that the women rate their experience of care in terms of psycho-social outcomes more positively in midwifery units compared to OUs [43, 44, 60–63]. In our study of FMU care, we also found that the effect of FMU care on women’s birth experiences differed by women’s level of social disadvantage and that FMU care had a mitigating effect on the effect of social disadvantage on birth experience . With this increased evidence on the safety and quality of care in midwifery units , it seems likely that more low-risk women will choose FMU settings for birth if they are available.
In general, non-OU settings for birth have been found to be the choice of the group of more mature, better-educated, middle-class women of socially privileged backgrounds [44, 58, 65–67]. However, proximity is also seen to exert a strong influence on women’s choice of birthplace [68–70]. With increasing distance between maternity units as a result of centralisation, the social characteristics of women choosing a non-OU service may become more mixed .
There is limited evidence concerning birth outcomes of FMU versus OU care for disadvantaged women. A systematic literature search identified only one study on perinatal and maternal outcomes in FMUs, which explored the interaction between birthplace and perinatal and maternal birth outcome. This study concluded that outcomes did not differ by women’s level of social disadvantages . Our study of two FMUs located in community hospitals in peripheral, low education and low income areas, provides a rare opportunity to investigate the outcomes and suitability of FMU care for socially disadvantaged women.
The aim was to study the whether the effect of intended birthplace on perinatal and maternal morbidity, birth interventions and use of pain relief and upright position for birth among low risk women intending to give birth in two FMU versus two OU in Denmark differed by level of social disadvantage.
The study is reported in accordance with the STROBE requirements for observational studies [72, 73].
Our study of the literature led us to hypothesise that in the present sample of low risk women where all frontline care in both groups are provided by midwives in the context of a public health system, the effect of birthplace on perinatal and maternal morbidity would not differ by women’s level of education.
For disadvantaged women we hypothesised that FMU care, with its focus on social support, individualised care and shared decision-making, would support the likelihood of spontaneous, uncomplicated birth, water birth and use of water tub and upright position for birth when compared to disadvantaged women intending to give birth in an OU.