- Email: [email protected]
Maternal underweight and child growth and development – Authors' reply
Correspondence
3·0
0–3 months 4–6 months
Odds ratio of child underweight
2·5 2·0 1·5 1·0 0·5 0 <18·5
25·0–29·9
18·5–24·9 (reference)
≥30·0
Maternal body-mass index (kg/m2)
Figure: Child underweight at 0–3 months and 4–6 months after delivery relative to maternal body-mass index (BMI) BMI 25·0–29·9 kg/m2=overweight. BMI ≥30·0 kg/m²=obese. Error bars represent 95% CIs. Surveys selected for this analysis are those that were used by Cresswell and colleagues.1
1·8–2·5), whereas maternal overweight and obesity were protective among infants by 4–6 months (0·8, 0·7–1·0, and 0·7, 0·5–0·99, respectively; figure). Maternal obesity, although increasing in many resource-poor countries, remains concentrated among mothers with high socioeconomic status.4 In 25 of 27 countries analysed by Cresswell and colleagues (table 11), maternal rates of underweight substantially exceed those of obesity, with pooled prevalences of 16·6% versus 5·3%, respectively. In Africa, the prevalence of underweight in children younger than 5 years is 21·9%, with underweight being the greatest source of mortality in resource-poor settings.3,5 The findings related to the increased risk of neonatal death in overweight and obese mothers should not divert focus from the health burden faced by underweight mothers and the adverse effects on their children’s growth. We must move beyond an agenda that focuses solely on survival to also consider child growth and development. We declare that we have no conflicts of interest.
Fahad Razak, Jocelyn E Finlay, *S V Subramanian [email protected] University of Toronto, Toronto, ON, Canada (FR); Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, MA 02115, USA (FR, SVS); and Harvard Center for Population and Development Studies, Cambridge, MA, USA (JEF) www.thelancet.com Vol 381 February 23, 2013
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Cresswell JA, Campbell OM, De Silva MJ, Filippi V. Effect of maternal obesity on neonatal death in sub-Saharan Africa: multivariable analysis of 27 national datasets. Lancet 2012; 380: 1325–30. Black RE, Allen LH, Bhutta ZA, et al. Maternal and child undernutrition: global and regional exposures and health consequences. Lancet 2008; 371: 243–60. Persson LÅ, Arifeen S, Ekström E-C, et al. Effects of prenatal micronutrient and early food supplementation on maternal hemoglobin, birth weight, and infant mortality among children in Bangladesh: the MINIMat randomized trial. JAMA 2012; 307: 2050–59. Subramanian S, Finlay JE, Neuman M. Global trends in body-mass index. Lancet 2011; 377: 1915–16. Million Death Study Collaborators. Causes of neonatal and child mortality in India: a nationally representative mortality survey. Lancet 2010; 376: 1853–60.
Authors’ reply We completely agree that maternal underweight continues to be an important public health issue. Nevertheless, levels of maternal underweight and maternal overweight are similar in sub-Saharan Africa, and thus we believe discussion of both issues is merited. Our finding of no association between neonatal mortality and maternal underweight is entirely consistent with the results of several previously published cohort studies that use high-quality data from Denmark,1 Sweden,2 and the UK,3 for which data on prepregnancy or early pregnancy body-mass index were available, and birth registration
systems comprehensive. Maternal underweight is associated with some adverse pregnancy outcomes that lead to neonatal mortality such as low birthweight and preterm delivery; however others, including preeclampsia and gestational diabetes, are less common in underweight women.4 Mortality, and its constituent causes, differ substantially in the neonatal period from factors that affect child health more broadly.5 In our paper, we interpret the noted attenuation of effect during the late neonatal period as suggesting that the mechanism is likely to be related to intrapartum events, rather than factors such as low birthweight, which can lead to death after a lag. The association between maternal underweight and poor child growth is well established, and is replicated in the analysis by Razak and colleagues; we suggest that it might be interesting to investigate mortality and underweight as outcomes simultaneously. We do not wish to detract from the importance of maternal underweight. However, low-income countries now face a double burden, with increased risk at both ends of the weight spectrum; a holistic approach is needed. We declare that we have no conflicts of interest.
*Jenny A Cresswell, Oona M R Campbell, Mary J De Silva, Véronique Filippi [email protected] London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK 1
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3
4
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Kristensen J, Vestergaard M, Wisborg K, Kesmodel U, Secher NJ. Pre-pregnancy weight and the risk of stillbirth and neonatal death. BJOG 2005; 112: 403–08. Cnattingius S, Bergstrom R, Lipworth L, Kramer MS. Prepregnancy weight and the risk of adverse pregnancy outcomes. N Engl J Med 1998; 338: 147–52. Tennant PW, Rankin J, Bell R. Maternal body mass index and the risk of fetal and infant death: a cohort study from the North of England. Hum Reprod 2011; 26: 1501–11. Sebire NJ, Jolly M, Harris J, Regan L, Robinson S. Is maternal underweight really a risk factor for adverse pregnancy outcome? A populationbased study in London. BJOG 2001; 108: 61–66. Lawn JE, Kerber K, Enweronu-Laryea C, Cousens S. 3·6 million neonatal deaths—what is progressing and what is not? Semin Perinatol 2010; 34: 371–86.
627
3·0
0–3 months 4–6 months
Odds ratio of child underweight
2·5 2·0 1·5 1·0 0·5 0 <18·5
25·0–29·9
18·5–24·9 (reference)
≥30·0
Maternal body-mass index (kg/m2)
Figure: Child underweight at 0–3 months and 4–6 months after delivery relative to maternal body-mass index (BMI) BMI 25·0–29·9 kg/m2=overweight. BMI ≥30·0 kg/m²=obese. Error bars represent 95% CIs. Surveys selected for this analysis are those that were used by Cresswell and colleagues.1
1·8–2·5), whereas maternal overweight and obesity were protective among infants by 4–6 months (0·8, 0·7–1·0, and 0·7, 0·5–0·99, respectively; figure). Maternal obesity, although increasing in many resource-poor countries, remains concentrated among mothers with high socioeconomic status.4 In 25 of 27 countries analysed by Cresswell and colleagues (table 11), maternal rates of underweight substantially exceed those of obesity, with pooled prevalences of 16·6% versus 5·3%, respectively. In Africa, the prevalence of underweight in children younger than 5 years is 21·9%, with underweight being the greatest source of mortality in resource-poor settings.3,5 The findings related to the increased risk of neonatal death in overweight and obese mothers should not divert focus from the health burden faced by underweight mothers and the adverse effects on their children’s growth. We must move beyond an agenda that focuses solely on survival to also consider child growth and development. We declare that we have no conflicts of interest.
Fahad Razak, Jocelyn E Finlay, *S V Subramanian [email protected] University of Toronto, Toronto, ON, Canada (FR); Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, MA 02115, USA (FR, SVS); and Harvard Center for Population and Development Studies, Cambridge, MA, USA (JEF) www.thelancet.com Vol 381 February 23, 2013
1
2
3
4
5
Cresswell JA, Campbell OM, De Silva MJ, Filippi V. Effect of maternal obesity on neonatal death in sub-Saharan Africa: multivariable analysis of 27 national datasets. Lancet 2012; 380: 1325–30. Black RE, Allen LH, Bhutta ZA, et al. Maternal and child undernutrition: global and regional exposures and health consequences. Lancet 2008; 371: 243–60. Persson LÅ, Arifeen S, Ekström E-C, et al. Effects of prenatal micronutrient and early food supplementation on maternal hemoglobin, birth weight, and infant mortality among children in Bangladesh: the MINIMat randomized trial. JAMA 2012; 307: 2050–59. Subramanian S, Finlay JE, Neuman M. Global trends in body-mass index. Lancet 2011; 377: 1915–16. Million Death Study Collaborators. Causes of neonatal and child mortality in India: a nationally representative mortality survey. Lancet 2010; 376: 1853–60.
Authors’ reply We completely agree that maternal underweight continues to be an important public health issue. Nevertheless, levels of maternal underweight and maternal overweight are similar in sub-Saharan Africa, and thus we believe discussion of both issues is merited. Our finding of no association between neonatal mortality and maternal underweight is entirely consistent with the results of several previously published cohort studies that use high-quality data from Denmark,1 Sweden,2 and the UK,3 for which data on prepregnancy or early pregnancy body-mass index were available, and birth registration
systems comprehensive. Maternal underweight is associated with some adverse pregnancy outcomes that lead to neonatal mortality such as low birthweight and preterm delivery; however others, including preeclampsia and gestational diabetes, are less common in underweight women.4 Mortality, and its constituent causes, differ substantially in the neonatal period from factors that affect child health more broadly.5 In our paper, we interpret the noted attenuation of effect during the late neonatal period as suggesting that the mechanism is likely to be related to intrapartum events, rather than factors such as low birthweight, which can lead to death after a lag. The association between maternal underweight and poor child growth is well established, and is replicated in the analysis by Razak and colleagues; we suggest that it might be interesting to investigate mortality and underweight as outcomes simultaneously. We do not wish to detract from the importance of maternal underweight. However, low-income countries now face a double burden, with increased risk at both ends of the weight spectrum; a holistic approach is needed. We declare that we have no conflicts of interest.
*Jenny A Cresswell, Oona M R Campbell, Mary J De Silva, Véronique Filippi [email protected] London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK 1
2
3
4
5
Kristensen J, Vestergaard M, Wisborg K, Kesmodel U, Secher NJ. Pre-pregnancy weight and the risk of stillbirth and neonatal death. BJOG 2005; 112: 403–08. Cnattingius S, Bergstrom R, Lipworth L, Kramer MS. Prepregnancy weight and the risk of adverse pregnancy outcomes. N Engl J Med 1998; 338: 147–52. Tennant PW, Rankin J, Bell R. Maternal body mass index and the risk of fetal and infant death: a cohort study from the North of England. Hum Reprod 2011; 26: 1501–11. Sebire NJ, Jolly M, Harris J, Regan L, Robinson S. Is maternal underweight really a risk factor for adverse pregnancy outcome? A populationbased study in London. BJOG 2001; 108: 61–66. Lawn JE, Kerber K, Enweronu-Laryea C, Cousens S. 3·6 million neonatal deaths—what is progressing and what is not? Semin Perinatol 2010; 34: 371–86.
627