International Journal of Epidemiology 2001;30:60-65
© International Epidemiological Association 2001
Special Theme: Fetal Origins of Health and Disease |
Lowered weight gain during pregnancy and risk of neural tube defects among offspring
a March of Dimes Birth Defects Foundation, California Birth Defects Monitoring Program, Emeryville, CA, USA.
b Division of Research, Kaiser Permanente Medical Care Program, Oakland, CA, USA.
c Divisions of Epidemiology and Biostatistics, University of California, Berkeley, CA, USA.
Reprint requests to: Dr Shaw, California Birth Defects Monitoring Program, 1900 Powell St. Suite 1050, Emeryville, CA 94608, USA.
Abstract
Background Maternal nutritional factors have been implicated in the complex aetiology of neural tube defects (NTD). We investigated whether the amount of weight a woman gained during pregnancy was associated with her risk of delivering an infant with an NTD.
Methods We conducted a population-based case-control study within the cohort of 708 129 live births and fetal deaths occurring in selected California counties in 1989–1991. Face-to-face interviews were conducted with mothers of 538 (88% of eligible) NTD cases (including those electively terminated, stillborn, or liveborn) and with mothers of 539 (88%) non-malformed liveborn controls within an average of 5 months from the term delivery date. Respondent-reported weight gain during pregnancy (kg) was analysed. Risks of infants having NTD were estimated among women who gained <10kg compared to those who gained 
10kg during 38 week gestations.
Results Compared to women who gained 10kg, an increased risk for NTD offspring was observed among women who gained <10kg (odds ratio [OR] = 3.2, 95% CI : 2.3–4.6). The OR was 5.0 (95% CI : 2.6–9.7) among those women who gained <5 kg during pregnancy. The increased risk was not attributable to maternal non-use of a multivitamin containing folic acid, diabetes, NTD-pregnancy history, age, race/ethnicity, education, gravidity, alcohol use, cigarette use, prepregnant obesity, low socioeconomic status, dieting, nausea, nor to lower dietary intakes of folate, zinc, energy, protein, fat, carbohydrates, and methionine. An increased risk was observed even after simultaneous adjustment for most of these factors (OR = 2.2, 95% CI : 1.2–3.8). The risk associated with gaining <10kg was greater for anencephaly, but still elevated for spina bifida.
Conclusions We did not have information on weight gain during early pregnancy. Because weight gain during the relevant embryological period for NTD (first month post-conception) is relatively small and often variable, it seems less likely that elevated NTD risks indicate a causal association between lowered weight gain throughout pregnancy and abnormal development of the neural tube. It seems more likely that lowered weight gain is a consequence of carrying an NTD-affected fetus. However, what this consequence is and why risk was substantially larger for anencephaly is unknown.
Keywords Congenital anomalies, anencephaly, birth defects, pregnancy, teratogens, aetiology, spina bifida, body mass index
Accepted 8 February 2000
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  T. Wolff, C. T. Witkop, T. Miller, and S. B. Syed Folic Acid Supplementation for the Prevention of Neural Tube Defects: An Update of the Evidence for the U.S. Preventive Services Task Force Ann Intern Med, May 5, 2009; 150(9): 632 - 639. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. J. Stothard, P. W. G. Tennant, R. Bell, and J. Rankin Maternal Overweight and Obesity and the Risk of Congenital Anomalies: A Systematic Review and Meta-analysis JAMA, February 11, 2009; 301(6): 636 - 650. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. L. Carmichael, G. M. Shaw, D. M. Schaffer, C. Laurent, and S. Selvin Dieting Behaviors and Risk of Neural Tube Defects Am. J. Epidemiol., December 15, 2003; 158(12): 1127 - 1131. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. B. Terry and E. Susser Commentary: The impact of fetal and infant exposures along the life course Int. J. Epidemiol., February 1, 2001; 30(1): 95 - 96. [Full Text] [PDF]
|
|
|
|
|
|
D. A Leon Commentary: Getting to grips with fetal programming--aspects of a rapidly evolving agenda Int. J. Epidemiol., February 1, 2001; 30(1): 96 - 98. [Full Text] [PDF]
|
|