# Presentation: 226307

## Prenatal WIC Participation and the Adequacy of Gestational Weight Gain among Florida's Medicaid Population

- Leticia Hernandez, MS
- David Goodman, PhD, MS
- William M Sappenfield, MD, MPH
- Debbie Eibeck, MS, RD, LD
- Jane Menges, MS, RD, LD

**Dec 2007**
**MCH Epi Conference**

## Background

- Recent conflicting reports on the association of WIC participation with birth outcomes.
- The Florida WIC program:
- Provides counseling on recommended gestational weight gain (GWG).
-  Emphasizes foods of high nutritional quality.
- Gestational weight gain is associated with birth weight (Frederick et al., 2007).

**Notes:**
There have been conflicting reports about the efficacy of special supplemental nutrition program for women, infant, and children (WIC) on pregnancy and birth outcomes,

The WIC program was established in 1972, in order to enhance the nutritional status of these vulnerable groups.
In WIC program clients receive counseling and education on weight gain and dietary. A licensed dietitian/nutritionist must develop a high risk nutrition care plan for all medically high risk clients.

According to the authors, gestational weight gain was positively associated with infant births weight. Low gestational weight gain was associated with twice the risk of LBW.

## Study Aims

- Among women on Medicaid, who experienced a singleton live birth, what is the association between WIC participation and:
-  Recommended gestational weight gain?
-  Low birth weight (< 2,500 grams)?
-  Weight gain as a mechanism to prevent LBW?

**Notes:**
Previous studies have indicated women participating on WIC, particularly Medicaid eligible women, have better outcomes than those who do not participate on WIC. 

## Methods

**Data:** Florida Pregnancy Risk Assessment Monitoring System (PRAMS) merged with birth data, 2000-2005.
**Design:** Cross sectional study.
**Population:** Women who reported being on _Medicaid_ at the time of delivery and experienced a _singleton_ delivery.

**Notes:**

PRAMS the risk assessment monitoring system is a joint surveillance project between the FDOH and the US Centers for Disease Control and Prevention designed to monitor the physical, economic, and social   health of Florida’s mothers and newborns. PRAMS is mail survey with telephone follow up. Prams rate of answer is approximately 76%

Multiple gestations were excluded to avoid the confounding effects of multiple births on gestational weight gain

## Methods

**Analysis:** Logistic regression used to describe association between WIC participation and the outcomes of:
- Gestational weight gain (Institute of Medicine (IOM) guidelines)
-  Low birth weight (< 2,500 grams)
**Software**:  Weighted estimates using STATA SE, V.9.2.

## IOM Recommended Gestational Weight Gain*

**Weight Status**

**BMI Range (kg/m****2****)**

**Recommended** **Weight Gain**

- Underweight

- Normal

- Overweight

- Obese

- < 19.8

- 19.8 - 26

- 26.1 - 29

- > 29

- 28 – 40 Lbs

- 25 – 35 Lbs**     **

- 15 – 25 Lbs

- 15 Lbs

*** **Nutrition During Pregnancy: Part I: Weight Gain, Part II: Nutrient Supplements. 1990. _[http://books.nap.edu/catalog/1451.html](http://books.nap.edu/catalog/1451.html)_

**Notes:**
Pregnancy Nutrition Surveillance System uses BMI cutoffs for pregnant women that are recommended by the Institute of Medicine. 

## Methods

- Association adjusted for:
- Race/Ethnicity
- Maternal age
- Maternal education
- Marital status
- Entry into prenatal care
- Pregnancy intent
- Smoking (Current & Quit)
- Parity
- Body mass index (BMI)
- Adequacy of prenatal care

**Notes:**
This is the list of variables used in the model

## Results: Study Population 

**Total**

**Unweighted (n)**

**Weighted (N)**

- On Medicaid at Delivery

-      On Medicaid & WIC

-      On Medicaid not  WIC

- # of Surveys

-         13,761

-       6,403

-   4,604 **(71.2%)**

- 1,449 **(22.6%)**

- 1,244,761

-   542,111

- 415,180 **(76.6%)**

- 124,795 **(22.6%)**** **

- Singletons

- 12,930

- 1,223,164

- Unknown

- 350 **(5.5%)**

- 2,136 **(0.4%)**

**Study population: FL PRAMS 2000-2005**

**Notes:**
What does Florida PRAMS over sample on? So, essentially they over sample based on age, low birth weight, and race.  

## Results: Gestational Weight Gain 

**Distribution of gestational weight gain categories among FL’s Medicaid population that experienced a singleton live birth, by WIC participation: 2000-2005**

**Notes:**
We did not find a significant difference between the WIC and not on WIC percentage, but we can get an idea that women on WIC are the ones with more risk to not get a  normal gestational weight gain.

## Results : Gestational Weight Gain

**Adjusted odds ratio (AOR)* for inadequate and excessive GWG: FL’s Medicaid population that experienced a singleton live birth, 2000-2005 **

|  | Inadequate
AOR (95% CI) |   Excessive 
AOR (95% CI) |
| --- | --- | --- |
| 
On WIC |  
1.2 (0.9 – 1.7)  |  
1.1 (0.8 – 1.4)  |

- *Adjusted for race/ethnicity, age, education, marital status, prenatal care, smoke, parity, body mass index, and adequacy of prenatal care

**Notes:**
Medicaid women on WIC have similar risk of inadequate gestational weight gain as Medicaid women not on WIC.

## Results : Gestational Weight Gain

|  | Inadequate 
AOR (95% CI) | Excessive
AOR (95% CI) |
| --- | --- | --- |
| On WIC |  1.2 (0.9 – 1.7)  |  1.1 (0.8 – 1.4)  |
| Quit smoking during pregnancy |  0.5 (0.3 – 0.8)* |  1.8 (1.2 – 2.6)* |
| Underweight |  1.1 (0.8 – 1.5)  |  0.5 (0.4 – 0.7)* |
| Overweight |  0.5 (0.3 – 0.8)*        |  2.4 (1.7 – 3.3)* |
| Obese |  9.0 (5.0 – 16.1)* | 29.2 (16.6 – 51.3)* |
| Two or more children |  1.4 (1.0 – 1.8)*  |  0.6 (0.5 – 0.8)* |

- * Significant (p<0.05)

**Adjusted odds ratio (AOR)* for inadequate and excessive GWG: FL’s Medicaid population that experienced a singleton live birth, 2000-2005 **

- *Adjusted for race/ethnicity, age, education, marital status, prenatal care, smoke, parity, body mass index, and adequacy of prenatal care.

**Notes:**
Quitting smoking during pregnancy is associated with increasing the risk of excessive gestational weight gain, while is protective for getting inadequate weight gain.
Body mass index before pregnancy is a factor for getting an adequate gestational weight gain.
Having one or more children before the current child is a risk for getting inadequate gwg, and protective for  not having excessive weight gain.

## Results: Low Birth Weight

|  | Low Birth Weight AOR (95% CI) |
| --- | --- |
| 
On WIC
 | 
0.8 (0.6 - 0.9)
 |

**Adjusted odds ratio (AOR)* for low birth weight: FL’s Medicaid population that experienced a singleton live birth, 2000-2005 **

- *Adjusted for race/ethnicity, age, education, marital status, prenatal care, smoke, parity, body mass index, and adequacy of prenatal care

## Results: Low Birth Weight

|  | Low Birth Weight AOR (95% CI)  |
| --- | --- |
| On WIC | 0.8 (0.6 - 0.9) |
| Smoked during pregnancy | 2.0 (1.6 - 2.5) |
| Black | 2.0 (1.7 - 2.4) |
| Inadequate gestational weight gain | 2.0 (1.7 - 2.4) |
| Underweight | 1.5 (1.3 - 1.8) |
| Obese | 1.3 (1.1 - 1.6) |
| Overweight | 1.3 (1.0 - 1.6) |
| Not married | 1.3 (1.1 - 1.6) |
| Two or more children | 0.7 (0.6 - 0.8) |
| Excessive gestational weight gain | 0.6 (0.5 - 0.7) |

**Adjusted odds ratio (AOR)* for low birth weight: FL’s Medicaid population that experienced a singleton live birth, 2000-2005 **

- *Adjusted for race/ethnicity, age, education, marital status, prenatal care, smoke, parity, and body mass index.

**Notes:**
Smoking during pregnancy, black race, inadequate gestational weight gain, and BMI outside the healthy range are associated with experienced a low birth weight delivery.

## Unable to determine the date of entry into WIC, women entering WIC late in pregnancy would be still be classified as WIC.
The variable “On Medicaid” included only the women that said their delivery (vs. prenatal care) was paid by “Medicaid.”

Self-reported data, including heights, weights, and weight gain may introduce bias.

Potential for residual confounding.

- Limitations

- Unable to determine the date of entry into WIC, women entering WIC late in pregnancy would be still be classified as WIC.
- The variable “On Medicaid” included only the women that said their delivery (vs. prenatal care) was paid by “Medicaid.”
- Self-reported data, including heights, weights, and weight gain may introduce bias.
- Potential for residual confounding.

**Notes:**
Residual confounding is an extraneous variable in a statistical model that correlates with both the dependent variable and the independent variable, but is no including in the model. 

## Medicaid women participating in WIC have similar risk of inadequate and excessive gestational weight gain as Medicaid women not participating in WIC.

Quitting smoking during pregnancy is associated with decreased risk of inadequate weight gain and increase risk of excessive gestational weight gain

Prepregnancy BMI is associated with gestational weight gain.

- Quitting smoking during pregnancy is associated with decreased risk of inadequate weight gain and increase risk of excessive gestational weight gain
- Prepregnancy BMI is associated with gestational weight gain.

- Summary: Gestational Weight Gain

## Medicaid women participating in WIC have decreased risk of experiencing a low birth weight delivery.

Potential WIC benefit appears to be independent of gestational weight gain.

Black race, unmarried, smoking, BMI outside the healthy range, and inadequate gestational weight gain are significantly associated with experiencing a low birth weight delivery.

- Potential WIC benefit appears to be independent of gestational weight gain.
- Black race, unmarried, smoking, BMI outside the healthy range, and inadequate gestational weight gain are significantly associated with experiencing a low birth weight delivery.

- Summary: Low Birth Weight

## Further research is needed to better understand:

Determinants of WIC participation among pregnant women on Medicaid.

Relationship between GWG and the WIC program.

Potential mechanisms by which WIC impacts low birth weight.

Relationship of smoking cessation and excessive gestational weight gain.

- Implications

- Further research is needed to better understand:
- Determinants of WIC participation among pregnant women on Medicaid.
- Relationship between GWG and the WIC program.
- Potential mechanisms by which WIC impacts low birth weight.
- Relationship of smoking cessation and excessive gestational weight gain.

**Notes:**
Further research is needed to better understand the determinants of WIC participation among pregnant women on Medicaid, the relationship between GWG and the WIC program.
Potential mechanisms by which WIC impacts birth weight
Relationship of smoking cessation and excessive gwg.

## Angel Watson, MPH, RHA
Sohyun Park, PhD, MS, RD/KDA 

- Sohyun Park, PhD, MS, RD/KDA

- Acknowledgement

## Contact Information
Leticia Hernandez: Leticia_Hernandez@doh.state.fl.us 

- Leticia Hernandez: Leticia_Hernandez@doh.state.fl.us

- Thank you!