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