Mighty Mums - a lifestyle intervention at primary care level reduces gestational weight gain in women with obesity.

Background: Obesity (BMI ≥30) during pregnancy is becoming an increasing public health issue and is associated with adverse maternal and perinatal outcomes. Excessive gestational weight gain (GWG) further increases the risks of adverse outcomes. However, lifestyle intervention can help pregnant women with obesity to limit their GWG. This study evaluated whether an antenatal lifestyle intervention programme for pregnant women with obesity, with emphasis on nutrition and physical activity, could influence GWG and maternal and perinatal outcomes.

Methods: The intervention was performed in a city in Sweden 2011-2013. The study population was women with BMI ≥30 in early pregnancy who received standard antenatal care and were followed until postpartum check-up. The intervention group (n = 459) was provided with additional support for a healthier lifestyle, including motivational talks with the midwife, food advice, prescriptions of physical activity, walking poles, pedometers, and dietician consultation. The control group was recruited from the same (n = 105) and from a nearby antenatal organisation (n = 790).

Results: In the per-protocol population, the intervention group had significantly lower GWG compared with the control group (8.9 ± 6.0 kg vs 11.2 ± 6.9 kg; p = 0.031). The women managed to achieve GWG < 7 kg to a greater extent (37.1% vs. 23.0%; p = 0.036) and also had a significantly lower weight retention at the postpartum check-up (- 0.3 ± 6.0 kg vs. 1.6 ± 6.5 kg; p = 0.019) compared to the first visit. The most commonly used components of the intervention, apart from the extra midwife time, were support from the dietician and retrieval of pedometers. Overall compliance with study procedures, actual numbers of visits with logbook activity, and dietician contact correlated significantly with GWG. There was no statistically significant difference in GWG (10.3 ± 6.1 kg vs. 11.2 ± 6.9 kg) between the intervention and control groups in the intention-to-treat population.

Conclusion: Pregnant women with obesity who follow a lifestyle intervention programme in primary health care can limit their weight gain during pregnancy and show less weight retention after pregnancy. This modest intervention can easily be implemented in a primary care setting.

Trial registration: The study has been registered at ClinicalTrials.gov, Identifier: NCT03147079. May 10 2017, retrospectively registered.