Association Between Gestational Weight Association Between Gestational Weight Gain and Adverse Obstetric and Neonatal Gain and Adverse Obstetric and Neonatal
Outcomes Among Overweight WomenOutcomes Among Overweight Women
Aisha LangfordAisha LangfordSaint Louis University Saint Louis University School of Public HealthSchool of Public Health
December 7, 2006December 7, 2006
BackgroundBackground
~47% of U.S. women are overweight ~47% of U.S. women are overweight
(25.0 – 29.99 kg/m2)(25.0 – 29.99 kg/m2)
Overweight women have increased risk for:Overweight women have increased risk for:– PreeclampsiaPreeclampsia– Cesarean-sectionCesarean-section– Macrosomic babies Macrosomic babies – Fetal deathFetal death
National Center for Health Statistics 2006, Baeten et al 2001, Callaway et al 2006
IOM GuidelinesIOM Guidelines
In 1990, gestational weight guidelines In 1990, gestational weight guidelines were established to reduce adverse were established to reduce adverse pregnancy outcomespregnancy outcomes
Overweight women (26.0 – 29.0 kg/m2)Overweight women (26.0 – 29.0 kg/m2) recommended to gain 15 - 25 lbs during recommended to gain 15 - 25 lbs during
pregnancypregnancy
Existing ResearchExisting Research
IOM guidelines appropriate for normal weight IOM guidelines appropriate for normal weight womenwomen
Overweight women who gained within IOM Overweight women who gained within IOM recommendations reduced their risk for high recommendations reduced their risk for high birth weight (HBW) and pre-term birthbirth weight (HBW) and pre-term birth
High gestational weight gain is associated with High gestational weight gain is associated with short and long-term weight retention short and long-term weight retention
Only 30-40% of women met recommendationsOnly 30-40% of women met recommendations
Cogswell et al 1995, Dietz et al 2006, Linne et al 2004, Abrams et al 2000
Study QuestionStudy Question
Is there an association between gestational Is there an association between gestational weight gain and adverse obstetric and neonatal weight gain and adverse obstetric and neonatal outcomes among overweight women?outcomes among overweight women?
What amount of gestational weight gain What amount of gestational weight gain minimizes risk?minimizes risk?
Hypothesis: Meeting IOM guidelines reduces Hypothesis: Meeting IOM guidelines reduces risk of poor outcomes.risk of poor outcomes.
Study DesignStudy Design
Population-based cohort studyPopulation-based cohort study
MO birth certificate data from 1990 to 2004 MO birth certificate data from 1990 to 2004 (residents only)(residents only)
Exposure Categories:Exposure Categories:– Did not meet recommendations (<15 lbs)Did not meet recommendations (<15 lbs)– Met recommendations (15 - 25 lbs)Met recommendations (15 - 25 lbs)– Exceeded recommendations (>25 lbs)Exceeded recommendations (>25 lbs)
Eligibility CriteriaEligibility Criteria
35,576 singleton, full-term (> 37 wks) deliveries to overweight nulliparous 18-35
34,143 women without missing demographic or exposure data
<15 lbs
1787
5%
15-25 lbs
7205
21%
> 25 lbs
25151
74%
*BMI is self-reported *BMI is self-reported
Adverse OutcomesAdverse Outcomes
Preeclampsia (hypertension after 20Preeclampsia (hypertension after 20 thth week) week)
C-section (emergency and elective)C-section (emergency and elective)
Macrosomia (Macrosomia (>> 4000 grams) 4000 grams)
Low birth weight (<2500 grams)Low birth weight (<2500 grams)
Perinatal death (at Perinatal death (at >> 37 weeks – 28 days of life) 37 weeks – 28 days of life)
AnalysisAnalysis
Bivariate analysis with chi-squareBivariate analysis with chi-square
Risk %Risk %
Measure of Association – Relative RiskMeasure of Association – Relative Risk
Stratified analysis to identify confoundersStratified analysis to identify confounders
Mantel Haenszel pooled estimator of relative risk Mantel Haenszel pooled estimator of relative risk
95% Confidence Interval (CI) for precision95% Confidence Interval (CI) for precision
Demographic CharacteristicsDemographic Characteristics
<15 lbs<15 lbs
(n=1787)(n=1787)
15-25 lbs15-25 lbs
(n=7205)(n=7205)
>25 lbs>25 lbs
(n=25151)(n=25151)
Age* (%)Age* (%)
18-24 18-24 5757 5252 5454
25-30 25-30 3131 3535 3434
31-35 31-35 1212 1313 1212
Race/Ethnicity* (%)Race/Ethnicity* (%)
Non-Hispanic WhiteNon-Hispanic White 7979 8181 8484
Non-Hispanic Black Non-Hispanic Black 1616 1414 1313
Other Other 55 55 33
*p<.05
Demographic CharacteristicsDemographic Characteristics
<15 lbs<15 lbs
(n=1787)(n=1787)
15-25 lbs15-25 lbs
(n=7205)(n=7205)
>25 lbs>25 lbs
(n=25151)(n=25151)
EducationEducation* (%)* (%)
<high school <high school 1616 1111 1111
high school high school 3838 3636 3737
some college some college 2626 2727 2626
college pluscollege plus 2020 2626 2626
Medicaid* (%)Medicaid* (%) 4242 3636 3737
WIC* (%)WIC* (%) 4343 3838 3939
*p<.05
Demographic CharacteristicsDemographic Characteristics
<15 lbs<15 lbs
(n=1787)(n=1787)
15-25 lbs15-25 lbs
(n=7205)(n=7205)
>25 lbs>25 lbs
(n=25151)(n=25151)
Tobacco Use*(%)Tobacco Use*(%) 2121 1616 1515
Alcohol Use (%)Alcohol Use (%) 11 11 11
Inadequate prenatal Inadequate prenatal 1515 1313 1313
Male child*(%)Male child*(%) 5050 4949 5252
Diabetes*(%)Diabetes*(%) 55 33 33
Hypertension (%)Hypertension (%) 11 11 11
Cardiac Disease (%)Cardiac Disease (%) 0.30.3 0.60.6 0.50.5
*p<.05
Adverse OutcomesAdverse Outcomes < 15 lbs 15-25 lbs** >25 lbs Risk (%)
Risk (%) Risk (%)
Preeclampsia 4
6 9
C- Section 21
23 30
Macrosomia 4
6 14
LBW 5
3 2
Perinatal Death
0.3
0.2 0.2
* Adjusted for age** Reference group
Adverse Outcomes by 10lb CategoriesAdverse Outcomes by 10lb Categories
0
10
20
30
40
Under 5 6-14 15-24 25-34 35-44 45-54 55-64 Over 65
Ris
k %
Adverse Outcomes by 10lb CategoriesAdverse Outcomes by 10lb Categories
0
10
20
30
40
Under 5 6-14 15-24 25-34 35-44 45-54 55-64 Over 65
C-Section
Ris
k %
Adverse Outcomes by 10lb CategoriesAdverse Outcomes by 10lb Categories
0
10
20
30
40
Under 5 6-14 15-24 25-34 35-44 45-54 55-64 Over 65
C-Section
Macrosomia
Ris
k %
Adverse Outcomes by 10lb CategoriesAdverse Outcomes by 10lb Categories
0
10
20
30
40
Under 5 6-14 15-24 25-34 35-44 45-54 55-64 Over 65
C-Section
Macrosomia
Preeclampsia
Ris
k %
Adverse Outcomes by 10lb CategoriesAdverse Outcomes by 10lb Categories
0
10
20
30
40
Under 5 6-14 15-24 25-34 35-44 45-54 55-64 Over 65
C-Section
Macrosomia
Preeclampsia
LBW
Ris
k %
Relative Risk by Weight GainRelative Risk by Weight GainGain (lbs) Preeclampsia C-Section RR 95% CI
RR 95% CI
5 or Less
0.7 0.4-1.3 1.1 0.9-1.4
6-14
0.8 0.6-1.1 0.9 0.8-1.0
15-24
1.0 Reference 1.0 Reference
25-34
1.3 1.2-1.5 1.1 1.1-1.2
35-44
1.7 1.5-1.9 1.3 1.2-1.4
45-54
2.0 1.8-2.3 1.4 1.3-1.5
55-64
2.7 2.3-3.2 1.6 1.5-1.8
65+ 3.4 2.8-4.0 1.8 1.6-1.9
Relative Risk by Weight GainRelative Risk by Weight GainGain (lbs) Macrosomia LBW RR 95% CI
RR* 95% CI
5 or Less
0.8 0.5-1.4 1.8 1.1-3.1
6-14
0.6 0.5-0.8 1.7 1.3-2.2
15-24
1.0 Reference 1.0 Reference
25-34
1.5 1.4-1.7 0.7 0.6-0.9
35-44
2.1 1.8-2.3 0.5 0.4-0.6
45-54
2.7 2.4-3.1 0.5 0.4-0.7
55-64
3.1 2.7-3.6 0.6 0.4-0.9
65 + 3.7 3.2-4.3 0.6 0.4-1.0
StrengthsStrengths
First study to evaluate First study to evaluate multiple outcomesmultiple outcomes
Extended time period Extended time period (1990-2004)(1990-2004)
LimitationsLimitations
Low power for Low power for perinatal deathperinatal death
Misclassification bias Misclassification bias of exposureof exposure
Birth certificate dataBirth certificate data
ConclusionsConclusionsCurrent IOM recommendations (15-25 lbs) for Current IOM recommendations (15-25 lbs) for overweight women are appropriateoverweight women are appropriate
Overweight women should not gain more than 25lbsOverweight women should not gain more than 25lbs
Gaining 6-14lbs may reduce risk of preeclampsia, c-Gaining 6-14lbs may reduce risk of preeclampsia, c-section and macrosomiasection and macrosomia
Findings are consistent with previous work on HBW Findings are consistent with previous work on HBW and LBWand LBW
Public Health ImplicationsPublic Health Implications
Pre-conception planning and monitoring Pre-conception planning and monitoring through pregnancy for overweight womenthrough pregnancy for overweight women
Increased risk of developing obesityIncreased risk of developing obesity
Further research on gestational weight Further research on gestational weight gain in overweight womengain in overweight women
AcknowledgementsAcknowledgements
Corinne Joshu, MACorinne Joshu, MA
Thomas Myles, MDThomas Myles, MD
Jen Jen Chang, PhDJen Jen Chang, PhD
Terry Leet, PhDTerry Leet, PhD
Anjali Deshpande, PhDAnjali Deshpande, PhD
QuestionsQuestions
Sensitivity AnalysisSensitivity Analysis
Of 35,576 eligible women, 1433 were Of 35,576 eligible women, 1433 were excludedexcluded
Chi-square statistic used to compare Chi-square statistic used to compare missing data with complete datamissing data with complete data
Missing more likely to be 18-24, non-Missing more likely to be 18-24, non-Hispanic white, <high school, enrolled in Hispanic white, <high school, enrolled in Medicaid and WICMedicaid and WIC
Attributable Attributable Risk %Risk %
Population Population Attributable Attributable Risk %Risk %
<15 lbs<15 lbs
SGASGA 4141 1313
>25lbs>25lbs
PreeclampsiaPreeclampsia 4141 3535
C-sectionC-section 2323 1919
MacrosomiaMacrosomia 5252 2121
Adverse OutcomesAdverse Outcomes < 15 lbs 15-25 lbs** >25 lbs RR* 95% CI Risk
(%)
RR Risk (%)
RR* 95% CI Risk (%)
Preeclampsia 0.8 0.6-1.0 4 1.0
6 1.7 1.5-1.9 9
C- Section 0.9 0.8-1.0 21 1.0
23 1.3 1.2-1.4 30
Macrosomia 0.6 0.5-0.8 4 1.0
6 2.1 1.9-2.3 14
SGA 1.7 1.4-2.2 5 1.0
3 0.6 0.5-0.7 2
Perinatal Death
1.9 0.8-4.6 0.3 1.0
0.2 1.1 0.6-1.9 0.2
* Adjusted for age** Reference group
Adverse OutcomesAdverse Outcomes
Gestational Weight Gain (lbs)
Preeclampsia C-Section
RR* 95% CI
Risk (%) RR* 95% CI Risk (%)
Under 5 0.7 0.4-1.3 4 1.1 0.9-1.4 24 5-14 0.8 0.6-1.1 4 0.9 0.8-1.0 20 15-24 1.0 Reference 5 1.0 Reference 23 25-34 1.3 1.2-1.5 7 1.1 1.1-1.2 26 35-44 1.7 1.5-1.9 9 1.3 1.2-1.4 29 45-54 2.0 1.8-2.3 11 1.4 1.3-1.5 32 55-64 2.7 2.3-3.2 14 1.6 1.5-1.8 35 ≥ 65 3.4 2.8-4.0 18 1.8 1.6-1.9 39
*Adjusted for age
Adverse OutcomesAdverse Outcomes
Gestational Weight Gain (lbs)
Macrosomia SGA
RR* 95% CI
Risk (%) RR* 95% CI Risk (%)
Under 5 0.8 0.5-1.4 5 1.8 1.1-3.1 6 5-14 0.6 0.5-0.8 4 1.7 1.3-2.2 5 15-24 1.0 Reference 6 1.0 Reference 3 25-34 1.5 1.4-1.7 10 0.7 0.6-0.9 2 35-44 2.1 1.8-2.3 13 0.5 0.4-0.6 2 45-54 2.7 2.4-3.1 17 0.5 0.4-0.7 2 55-64 3.1 2.7-3.6 19 0.6 0.4-0.9 2 ≥ 65 3.7 3.2-4.3 23 0.6 0.4-1.0 2
*Adjusted for age
Demographic CharacteristicsDemographic Characteristics<15 lbs<15 lbs
(n=1787)(n=1787)
15-25 lbs15-25 lbs
(n=7205)(n=7205)
>25 lbs>25 lbs
(n=25151)(n=25151)
Age* Age* †† YoungerYounger OlderOlder OlderOlder
Race/Ethnicity* Race/Ethnicity* †† BlackBlack WhiteWhite WhiteWhite
Education* Education* †† LessLess MoreMore MoreMore
Medicaid*Medicaid* MoreMore LessLess LessLess
WIC*WIC* MoreMore LessLess LessLess
Tobacco*Tobacco* MoreMore LessLess LessLess
Diabetes*Diabetes* MoreMore LessLess LessLess
*p<.05
† Majority 18-24, Non-Hispanic white with high school education
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