Researchers, who analysed more than 50 years of pregnancy and mortality data, found that excessive gestational weight gain (GWG) was linked to increased risk for earlier death, and called for more guidance for pregnant women related to the potential risks of being overweight.
For women with a normal pre-pregnancy weight, excessive GWG was associated with a 9% (95% CI 1.01-1.18) increase in all-cause mortality, said Stefanie Hinkle, PhD, of the University of Pennsylvania Perelman School of Medicine in Philadelphia, and co-authors.
Women who were overweight prior to pregnancy and who had excessive GWG had a 12% (95% CI 1.01-1.24) increase in all-cause death, Hinkle and colleagues reported in The Lancet.
Those who were underweight pre-pregnancy but had excessive GWG had an 84% increased risk of cardiovascular-related mortality (95% CI 1.08-3.12) but not all-cause or diabetes-related mortality, they found. Normal-weight women with excessive GWG also saw increased risk of cardiovascular death (HR 1.20, 95% CI 1.04-1.37), but not diabetes-related mortality.
And overweight women also had an increased risk of diabetes-related mortality (HR 1.77, 95% CI 1.23-2.54) but not cardiovascular mortality, researchers found.
“The data gleaned from this study strongly indicate that excessive weight gain during pregnancy may contribute to the development of chronic diseases in the long term, thereby increasing the risk of premature mortality,” Hinkle told MedPage Today, noting that nearly half of pregnant people gain more weight than guidelines recommend.
“It underscores the pressing need to provide support and guidance to mothers-to-be to help them achieve healthy weight gain during pregnancy, thus mitigating the risk of future chronic diseases and early mortality,” she added.
The researchers assessed data from the Collaborative Perinatal Project (CPP), which enrolled 48 197 pregnant people at their first prenatal visit at 12 clinical centres from 1959 to 1966. Their vital status was ascertained as of 2016 for the CPP Mortality Linkage Study.
Ultimately, a total of 46 042 women were included, and the median follow-up was 52 years, by which time about 39% of participants had died. There were near-equal numbers of black and white participants (45.3% and 46.2%, respectively).
The researchers found no meaningful associations between GWG and mortality among women who were obese before pregnancy, which they theorised is because obese women already have higher risk for chronic conditions.
In addition, weight change below recommended levels was only associated with a reduced risk of diabetes-related death (HR 0.62, 95% CI 0.48-0.79) in people who had normal weight before pregnancy.
The study was limited by a lack of follow-up after delivery, “limiting the ability to understand the process for developing chronic diseases and assess how an individual's risk might be altered with postpartum interventions”, the authors wrote.
“Although existing literature has shown that weight gain within NAM recommendations is crucial for optimising pregnancy outcomes such as birth-weight, this study shows that for women without pre-pregnancy obesity, gestational weight gain might have a lasting effect on health beyond pregnancy, increasing mortality risk from cardiometabolic diseases.”
In an accompanying editorial, Dr Tomomi Kotani and Dr Sho Tano, both of the Nagoya University Graduate School of Medicine in Japan, cautioned that the findings should be interpreted with caution “to avoid alarming pregnant women, because this study is an observational prospective study, not a clinical trial”.
“Excessive GWG could result in weight retention after delivery and visceral fat accumulation, but further studies are needed,” they wrote.
“Healthcare professionals should be aware that those who had excess GWG are a population at high risk of cardiovascular mortality and should also consider some prevention strategies for cardiovascular disease,” they wrote, “although further research is needed to assess their validity”.
Study details
Gestational weight change in a diverse pregnancy cohort and mortality over 50 years: a prospective observational cohort study
Stefanie Hinkle, Sunni Mumford, Katherine Grantz, Pauline Mendola, James Mills, et al.
Published in The Lancet on 19 October 2023
Summary
Background
High weight gain in pregnancy is associated with greater postpartum weight retention, yet long-term implications remain unknown. We aimed to assess whether gestational weight change was associated with mortality more than 50 years later.
Methods
The Collaborative Perinatal Project (CPP) was a prospective US pregnancy cohort (1959–65). The CPP Mortality Linkage Study linked CPP participants to the National Death Index and Social Security Death Master File for vital status to 2016. Adjusted hazard ratios (HRs) with 95% CIs estimated associations between gestational weight gain and loss according to the 2009 National Academy of Medicine recommendations and mortality by pre-pregnancy BMI. The primary endpoint was all-cause mortality. Secondary endpoints included cardiovascular and diabetes underlying causes of mortality.
Findings
Among 46 042 participants, 20 839 (45·3%) self-identified as black and 21 287 (46·2%) as white. Median follow-up time was 52 years (IQR 45–54) and 17 901 (38·9%) participants died. For those who were underweight before pregnancy (BMI <18·5 kg/m2; 3809 [9·4%] of 40 689 before imputation for missing data]), weight change above recommendations was associated with increased cardiovascular mortality (HR 1·84 [95% CI 1·08–3·12]) but not all-cause mortality (1·14 [0·86–1·51]) or diabetes-related mortality (0·90 [0·13–6·35]). For those with a normal pre-pregnancy weight (BMI 18·5–24·9 kg/m2; 27 921 [68·6%]), weight change above recommendations was associated with increased all-cause (HR 1·09 [1·01–1·18]) and cardiovascular (1·20 [1·04–1·37]) mortality, but not diabetes-related mortality (0·95 [0·61–1·47]). For those who were overweight pre-pregnancy (BMI 25·0–29·9 kg/m2; 6251 [15·4%]), weight change above recommendations was associated with elevated all-cause (1·12 [1·01–1·24]) and diabetes-related (1·77 [1·23–2·54]) mortality, but not cardiovascular (1·12 [0·94–1·33]) mortality. For those with pre-pregnancy obesity (≥30·0 kg/m2; 2708 [6·7%]), all associations between gestational weight change and mortality had wide CIs and no meaningful relationships could be drawn. Weight change below recommended levels was associated only with a reduced diabetes-related mortality (0·62 [0·48–0·79]) in people with normal pre-pregnancy weight.
Interpretation
This study's novel findings support the importance of achieving healthy gestational weight gain within recommendations, adding that the implications might extend beyond the pregnancy window to long-term health, including cardiovascular and diabetes-related mortality.
MedPage Today article – Excessive Weight Gain in Pregnancy Tied to Earlier Death (Open access)
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