Dr-Romy Gaillard

Which Matters More? Pre-Pregnancy Obesity vs Pregnancy Weight Gain?

MedicalResearch.com Interview with:

Dr-Romy GaillardRomy Gaillard MD PhD
LifeCycle Project-Maternal Obesity and Childhood Outcomes Study Group
Erasmus MC

MedicalResearch.com: What is the background for this study?  

Response: Obesity among women of reproductive age is a major problem for society. Scientists have long known that maternal weight before and during pregnancy are associated with pregnancy outcomes. Gestational weight gain is necessary to ensure healthy development of the fetus, but too much weight gain is associated with a higher risk of pregnancy complications.

The magnitude of the associations of maternal weight before and during pregnancy with the risks of pregnancy complications, as well as the optimal amount of weight that especially obese women should gain during pregnancy were not well-known.

MedicalResearch.com: What are the main findings?

Response: Results from this new study showed that overweight and obesity at the start of pregnancy are common. Pregnancy complications in mothers and their infants occurred in 34% of women with a normal weight and in over 60% of women with severe obesity at the start of their pregnancy. Of all women with very severe obesity and a high amount of weight gain during their pregnancy, over 90% experienced pregnancy complications. The amount of weight gain during pregnancy had a much smaller association with the risk of pregnancy complications than weight before pregnancy. These findings have major implications for health care during pregnancy and at delivery. Rather than focusing on maternal weight gain during pregnancy, strategies are needed to optimize maternal weight before the start of pregnancy to improve pregnancy outcomes. 

MedicalResearch.com: What should readers take away from your report? 

Response: This study underlines the importance of optimizing maternal BMI before the start of pregnancy. Currently, many interventions focused on optimizing maternal dietary intake and physical activity during pregnancy have targeted weight gain from the second half of pregnancy onwards, but these studies have shown disappointing effects on pregnancy outcomes. Based on the findings from this study, we need to invest in the development of strategies to optimize maternal weight before the start of pregnancy in order to improve maternal and infant pregnancy outcomes. 

MedicalResearch.com: What recommendations do you have for future research as a result of this work?

Response: Existing guidelines on optimal gestational weight gain are available from the US Institute of Medicine. However, these guidelines have important limitations due to the previous available evidence. Optimal gestational weight gain guidelines were only based on a few pregnancy complications. It was also not possible to develop gestational weight gain recommendations by prepregnancy obesity severity grades, even though the prevalence of severe obesity within Western Countries is rising.

This new study assessed the optimal amount of gestational weight gain for women with prepregnancy underweight, normal weight, overweight and obesity grades 1-3. Optimal amounts of gestational weight gain based on the risk of common pregnancy complications defined in this study were lower than current recommendations for all obese women, suggesting that the current IOM recommendations may overestimate the optimal amount of weight obese women should gain during pregnancy. Studied common pregnancy complications within our study included preeclampsia, gestational hypertension, gestational diabetes, caesarean delivery, preterm birth, small or large size for gestational age at birth. Our findings highlight the importance for further studies focused on the optimal amount of gestational weight gain among severely obese women, also including adverse outcomes such as still birth and infant death, which were not available in our study. 

MedicalResearch.com: Is there anything else you would like to add?

 Response: These findings are the result of a large-scale international collaboration, led by the Erasmus MC, University Medical Center, Rotterdam, the Netherlands. We analysed more than 190,000 mother and child pairs from 25 studies from Europe and the USA. The research involved more than 60 international researchers from 16 countries who work together in the EU Horizon 2020 funded LifeCycle Project – Maternal Obesity and Childhood Outcomes Group. The LifeCylce Project (www.lifecycle-project.eu) is a large collaboration focused on innovative research on the role of novel integrated markers of early-life stressors that influence health across the lifecycle using an open and long-term network of pregnancy and birth cohorts. The work was supported by more than 100 research funders including the European Union Horizon2020 funding scheme.


LifeCycle Project-Maternal Obesity and Childhood Outcomes Study Group. Association of Gestational Weight Gain With Adverse Maternal and Infant Outcomes. JAMA. 2019;321(17):1702–1715. doi:10.1001/jama.2019.3820

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May 9, 2019 @ 9:52 pm 

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