Our study is the first Victorian-based analysis of a specialised antenatal clinic for women with Class III obesity in a non-tertiary hospital. Our study demonstrates the demographic differences between women with a body mass index (BMI) of 40kg/m2 who attended the Obesity, Pregnancy and Lifestyle (OPAL) clinic to those who received standard antenatal care at Northern Health. It also describes the level of antenatal attention received by the two groups, as well as the rates of obstetric and neonatal outcomes.
In line with previous studies of the population of pregnant women attending Northern Health, our study demonstrates that women with an elevated BMI experience a high degree of obstetric and neonatal complications, as well as an increased rate of birth interventions (3). This is also consistent with the broader literature describing the risks associated with maternal obesity in pregnancy.
Our study reveals that there are significant demographic differences between the population of women enrolled in the OPAL clinic compared to those receiving standard antenatal care. OPAL women are more likely to be younger, to be primiparous and to be born in Australia or New Zealand. The reason for these demographic differences is not currently clear, however we can speculate that this may be because women who are younger, primiparous and Australian or NZ-born are more likely to be health conscious and therefore more willing to engage in specialist care through the OPAL clinic. Conversely, procedures during booking in may be leading to these women being selectively targeted for care through the OPAL clinic. What this does clearly demonstrate is that cultural background has an impact on the way women engage with health care during their pregnancy, and that this needs to be taken into account in the design and recruitment processes of pregnancy care services.
Notably, the OPAL clinic also recruited no women of an Aboriginal or Torres Strait Islander background. However, this is most likely because there is a culturally safe service that already exists in the Koori Maternity Clinic to service the needs of Aboriginal and Torres Strait Islander women, as opposed to these women not being engaged in antenatal care.
Our study demonstrates an increase in antenatal attention provided by the OPAL clinic. On average, women in the OPAL clinic attended significantly more antenatal appointments than women in standard antenatal care. This may indicate that the OPAL clinic was able to achieve a greater engagement in antenatal care. A key factor in this may enhanced continuity of care through consistency in the health care provider. Women in the OPAL clinic were seen by the same dedicated clinic obstetrician and midwife, compared to those in standard care who did not necessarily have this same consistency. Continuity of midwife care has been shown to be an important factor in increasing maternal satisfaction with antenatal care in low risk pregnancies (21), however there is limited research into the application of this practice into high risk pregnancies such as those complicated by maternal obesity. An obesity-sensitive approach by the health care providers in the OPAL clinic may have also contributed to increased engagement in care. The OPAL clinic offers an opportunity for women with high risk pregnancies and a risk of stigma who may not have access to private care to have an enhanced antenatal care experience.
Our study demonstrates the women in the OPAL clinic had a lower gestational age of delivery compared to women in standard antenatal care (38.3 weeks vs 38.5 weeks). However, there was no difference in the rate of pre-term deliveries between the two groups. Due to the complications associated with obesity during pregnancy, including increased rates of gestational diabetes mellitus, macrosomia, pre-eclampsia and stillbirth, timing of delivery is often planned, either via induction of labour or elective caesarean section (19). Safer Care Victoria guidelines recommend that delivery for women with a BMI ≥ 50kg/m2 occur at 38-39 weeks. The earlier gestational age of delivery may reflect an increased level of surveillance during antenatal care through the OPAL clinic and thus planned timing of delivery.
We were not able to demonstrate a reduction in excessive gestational weight gain for women in the OPAL clinic compared to standard antenatal care. This may be because women in standard antenatal care were more likely to present for antenatal care for the first time later in their pregnancy (median gestational age of booking 12.2 weeks vs 16.4 weeks) due to the selection criteria of the OPAL clinic requiring booking in to occur prior to 18 weeks gestation. This may have led to initial weight measured being higher as it occurred later in the pregnancy, therefore leading to a lower gestational weight gain calculation. Furthermore, maternal weight at term was not recorded for many women, forcing us to rely on the final maternal weight recorded at an antenatal visit. This inconsistency in recording may have impacted on the accuracy of our calculation.
At this stage, our study is not able to demonstrate an improvement in obstetric and neonatal outcomes through the OPAL clinic. Currently numbers are too small to demonstrate changes in outcomes between the two groups, especially for rarer obstetric and neonatal outcomes. However, there is a trend towards a reduction in late preterm births, fewer instrumental deliveries and a reduced rate of shoulder dystocia. Further follow up is required to investigate these outcomes.
The lack of improvement in obstetric and neonatal outcomes is not entirely surprising as results from other studies have been mixed, showing inconsistent or minimal improvements in outcomes with antenatal dietary and lifestyle interventions. A Cochrane systematic review revealed limited impact of diet and/or exercise intervention on many obstetric and all neonatal outcomes (13). There are a number of barriers for dietary and lifestyle interventions during pregnancy, including physiological changes such as nausea and cravings, a short period of intervention (especially before diagnosis of GDM) and concerns over foetal growth with high intensity interventions (22).
Limitations
As this study was conducted retrospectively, there was a reliance on patient records which were not always complete. In particular, not all women had a recorded maternal weight at term, meaning that there was inconsistency in the precise gestation of the final maternal weight and therefore the calculation of gestational weight gain.
Given the non-randomised design of the study as we were investigating a clinic that was currently functioning outside the scope of a clinic trial, there were significant demographic differences between women in the OPAL clinic and those in standard antenatal care. This impacts on our ability to compare outcomes between the two groups. However, this demographic difference highlights the way in which the clinic is currently functioning, revealing that a particular subset of obese women are being targeted by the clinic through their own desires or the recruitment process.
The OPAL clinic was started in July 2018. This limits the number of participants we were able to include in this study. This limitation in sample size impacts on our ability to assess any changes in rarer obstetric and neonatal outcomes.
Finally, although women in the OPAL clinic were provided with specific dietary and lifestyle advice, this study did not measure the level of behaviour change inspired by this advice compared to antenatal care. This means we are unable to tell whether any change in outcomes was due to ineffective measures or failure to implement said measures.
Implications for future practice, policy and future research
This study is among the first to investigate the impact of an obesity-specific antenatal clinic in a Victorian hospital. The information may assist in the ongoing development and expansion of the OPAL clinic and influence pregnancy care for obese woman more broadly.
Considering the demographic differences between women enrolled in the OPAL clinic and those receiving standard antenatal care, further investigation into the reason why this is the case is important in order to ensure we are providing culturally safe care to all women and offering specialised care in an equitable and unbiased way. Specifically, focusing on the engagement of women from diverse cultural backgrounds is a priority, especially given the diverse population serviced by Northern Health.
OPAL women had extra antenatal attention, on average having one extra clinic appointment during their antenatal period. This may be due to better engagement in antenatal care. This is especially important for women who have an elevated BMI as they may experience stigma and discussion and measurement of weight can be a sensitive issue. Future research should focus on the experience of women who have attended the OPAL clinic and how it compares to standard antenatal care and their other experiences in the healthcare system.
Given these promising findings, the OPAL clinic should be expanded to increase its capacity to provide specialised and sensitive antenatal care to women with class III obesity.