WIC Linked Prenatal/Postpartum MICA - Variable Definitions

Optional variables

The particular WIC measures we provide data for in each MICA.

Indicators

Individual categories within an optional variable that are frequently requested. MICA provides the opportunity to look all categories of each optional variable, or to select individual indicators of interest.

All WIC Linked Prenatal/Postpartum Participants

The WIC Prenatal-Postpartum MICA includes a record for each mother who delivered a live infant during a given calendar year if the infant was still alive at the postpartum visit. Only one record will be included for a woman with multiple births. Data are not reported for mothers with deceased infants or infants who were born alive but died prior to the first postpartum visit.

Age

The WIC Prenatal MICA age calculation differs from the WIC Postpartum MICA age calculation. In the WIC Prenatal MICA, the participant’s age is calculated from her date of birth to her date of last normal menses. This is her age at conception. In the WIC Postpartum MICA, the participant’s age is calculated from her date of birth to the date of her first WIC postpartum visit in the given year. This follows the procedure used by CDC. Age at first visit date is used in the WIC Postpartum MICA because date of last normal menses, which is collected on the prenatal record, is not available for those mothers only served by the postpartum program. Age at delivery is not reliable because delivery date is not verified. Because of these different calculations, the age of the same mother may be different in the WIC Prenatal MICA versus the WIC Postpartum MICA. In the WIC Linked Prenatal-Postpartum MICA, the prenatal age calculation (age at conception) is used. In all three MICAs, recorded ages of less than 10 years or more than 64 years are considered to be biologically implausible values and are classified as unknown.

Birth Weight

Birth weight is calculated from the Weight field on the Infants Born from This Pregnancy record, which is linked to the Postpartum record. The WIC Postpartum MICA includes the birth weight only for the first live birth of any pregnancy that occurred during the calendar year.

• Category definitions for 2009 and later:
• Low: 450 grams through less than 2500 grams
• Very low: 450 grams through less than 1500 grams
• Moderately low: 1500 grams through less than 2500 grams
• Normal: 2500 grams through 4000 grams
• High: Greater than 4000 grams through 8000 grams
• Unknown birth weight: Field was blank or included a biologically implausible value of less than 450 grams (approximately 1 lb) or more than 8,000 grams (approximately 17.6 lb). Infants with a birth weight of less than 450 grams typically do not survive.

Breastfeeding

Breastmilk is the most complete form of nutrition for infants, with a range of benefits for infant health, growth, immunity, and development. WIC encourages mothers to breastfeed for the first year of life. MOWINS collects information about breastfeeding in several different fields, which are used in combination to determine breastfeeding status.

Breastfed – Ever

• Several fields are used to determine if the mother ever breastfed her most recent infant. The first of these is her postpartum program type, as both program type and benefits are determined by the mother’s current breastfeeding status at her first postpartum WIC visit. If the mother’s program type was Breastfeeding, she is considered to have ever breastfed. For mothers whose program type was Nonbreastfeeding, the breastfeeding began field is compared to the postpartum visit date. If the mother had a breastfeeding began date that occurred before the postpartum visit date, she is considered to have breastfed even though she stopped before enrolling in WIC. This indicator is only reported for live births, as data are not collected for infants who died prior to the first postpartum visit.

Breastfed – Currently

• This indicator is calculated from the participant’s program type, as both program type and benefits are determined by the mother’s current breastfeeding status at her first postpartum WIC visit. This indicator is only reported for live births, as data are not collected for infants who died prior to the first postpartum visit.

Breastfeeding Currently – Fully

• The mother is currently breastfeeding and the only liquid provided to the infant is breastmilk. Older infants may be fully breastfeeding but also eating infant cereal, baby food, etc. This indicator is calculated for mothers with postpartum program type Breastfeeding by comparing the supplemental feeding began date to the postpartum visit date.

Breastfeeding Currently – Partially

• The mother is currently breastfeeding but is also providing some other form of liquid, such as water or formula, to the infant. This indicator is calculated for mothers with postpartum program type Breastfeeding by comparing the supplemental feeding began date to the postpartum visit date.

Delivery Type

Indicates whether delivery was vaginal or cesarean.

Drinking During Three Months Prior to Pregnancy

Alcohol consumption data are reported by the WIC participant as the average number of drinks per week during the three months prior to pregnancy and thus may be underreported.

Education

Education data are reported as the number of years of education which can be any whole number between 0 and 18 years. For mothers between the ages of 10 and 21, data are tested to ensure realistic education levels. Education status is classified as unknown if the difference between the mothers age and her education is less than 4 years (e.g. age 19 – 17 years of education = 2 years). This test is not required for mothers over the age of 21 as the possible years of education are all plausible using the stated formula. All reasonable education values are aggregated into the appropriate categories for MICA.

MICA Education Categories

• Less than high school diploma
• 8th grade or less
• 9th to 11th grade
• High school diploma
• 13 to 15 years
• College degree plus
• Unknown

Food Stamps – Receiving at WIC Prenatal/Postpartum Visit

Food Stamps, or the Supplemental Nutrition Assistance Program (SNAP), is administered by the Missouri Department of Social Services and provides food benefits to needy households. This indicator is a proxy for socioeconomic status and may be used to evaluate the impact of WIC referral services. To learn more about Food Stamps/SNAP, visit https://dss.mo.gov/fsd/fstamp/.

Full Term Low Birth Weight

This measure combines the low birth weight category (see Birth weight) and full-term and post-term pregnancy indicators (see Pregnancy duration) to create a single indicator of interest for studies of maternal and child health.

Hematocrit/Hemoglobin (Anemia)

Hematocrit and hemoglobin categories are determined using the 1998 CDC Guidelines for WIC Hematocrit/Hemoglobin Values Adjusted for Altitude and Smoking. In MICA, 18.0 is used as a lower biologically implausible value for hematocrit, and 6.0 is used as a lower biologically implausible value for hemoglobin.

WIC Hematocrit Values Adjusted for Altitude* and Smoking†, 1998 CDC Guidelines

*No altitude adjustment required for Missouri
†Assuming 20 cigarettes per pack

WIC Hemoglobin Values Adjusted for Altitude* and Smoking†, 1998 CDC Guidelines

*No altitude adjustment required for Missouri
†Assuming 20 cigarettes per pack

1. CDC. (April 3, 1998). 1998 CDC Guidelines for WIC Hematocrit/Hemoglobin Values Adjusted for Altitude and Smoking. MMWR 47(RR-3); 1-36. Accessed June 2, 2015, from http://wonder.cdc.gov/wonder/PrevGuid/m0051880/m0051880.asp.

Marital Status

MICA reports this indicator as married, not married, or unknown marital status. Individual responses such as single or divorced would result in numbers too small to report.

Medicaid – Receiving at WIC Prenatal/Postpartum Visit

Medicaid, also known as MO HealthNet in Missouri, is administered by the Missouri Department of Social Services and provides medical services to persons who meet certain eligibility requirements. To learn more about Medicaid/MO HealthNet, visit https://dss.mo.gov/fsd/msmed.htm. Medicaid status is reported at the time of the initial postpartum WIC visit. There may be participants who are not receiving Medicaid at the time of the initial WIC visit but receive Medicaid at some later point during their WIC participation; they are not included in the receiving data in the WIC Postpartum MICA. Medicaid status is collected on the Income History tab. Data are unavailable for 2009.  

Multivitamin Consumption Prepregnancy

This indicator is used to estimate the proportion of women consuming the recommended amount of folic acid from supplements. MOWINS collects data on multivitamin consumption during the month prior to pregnancy. This field was not required until mid-2010. This indicator has been included in MICA since 2011. NOTE: The WIC MICA reports daily multivitamin consumption, which is defined as multivitamin consumption 7 or more times per week. Other data sources may define this indicator differently.

Multivitamin Consumption During Pregnancy

This indicator is used to monitor adequate iron intake during pregnancy. The majority of women who report taking vitamins or minerals during pregnancy get the recommended dose of iron per day. This is a field in MOWINS but was not required until mid-2010. This indicator may be added to MICA for the 2011 data year. NOTE: The WIC MICA reports daily multivitamin consumption, which is defined as multivitamin consumption 7 or more times per week. Other data sources may define this indicator differently.

Number Born

This indicator provides the number of live births for one pregnancy. While there are fields for up to 8 infants in MOWINS, MICA reported indicators for Number born only include Singleton birth and Twin or other multiple birth as other breakdowns would result in numbers too small to report.

Parity – See Prior Live Births.

Pregnancy Duration

This indicator is calculated by the following formula (delivery date – last menstrual period date)/7. On WIC Postpartum MICA, this indicator is reported as unknown for women who were served in the Postpartum program only, as the last menstrual period date is collected on the Prenatal certification only and must be linked to the Postpartum record. Only gestations of 20 or more weeks are included for this indicator, because the WIC Postpartum MICA reports data only for live births, very few of which are born at less than 20 weeks gestation. The maximum gestation reported is 48 weeks. 

Category Definitions

• Preterm: 20 weeks through less than 37 weeks and one day of gestation
• Full term: 37 weeks and one day through 41 weeks gestation
• Postterm: 42 weeks through 48 weeks gestation
• Unknown: Actual Delivery Date or LMP Start Date is blank or gestation is less than 20 weeks (a biologically implausible value)

Pregnancy Spacing (Interpregnancy Interval)

This indicator is calculated by subtracting the Last Menstrual Period Start Date from the Last Pregnancy Ended date. Both of these fields are collected on the Prenatal record. Following a literature review, the WIC Data Group approved the use of interval ranges from an article in the February 2012 Journal of Community Health, which cites 18-23 months as ideal, with significant risk at less than 6 months and additional risk after 60 months. The USDA justification for WIC also defines 18 months as optimal. The denominator for the spacing indicators only includes mothers who are known to have a prior pregnancy and have known duration between pregnancies. Unknown status cannot be reliably determined because blank Last Pregnancy Ended date could mean unknown end date or that the current pregnancy is the mother’s first.2

2. Salihu, H. M., et. al. (2012 February). The impact of birth spacing on subsequent feto-infant outcomes among community enrollees of a federal healthy start project. Journal of Community Health, 37(1), 37-42.

Prepregnancy weight/Prepregnancy BMI

This indicator is calculated by converting Prepregnancy Height and Weight from the pregnancy record to BMI. Calculations were done in accordance with the 2009 recommendations from the Institute of Medicine.3

Categories Using 2009 Institute of Medicine Ranges

• Underweight: BMI is greater than 10.0 but less than 18.5.
• Normal weight: BMI is at least 18.5 but is no greater than 25.0.
• Overweight: BMI is greater than 25.0 but is not more than 30.0.
• Obese: BMI is greater than 30.0 but is no more than 80.0.
• Unknown: A record is considered to have unknown prepregnancy weight for height in the following situations.
• The prepregnancy weight field is blank or includes a biologically implausible value of less than 50 lbs or more than 500 lbs.
• The prepregnancy height field is blank or includes a biologically implausible value of less than 101.6 cm or greater than 212.9 cm.
• The calculated BMI field includes a biologically implausible value of less than 10.0 or greater than 80.0.

3. Institute of Medicine. Weight gain during pregnancy: reexamining the guidelines. Washington, DC: National Academies Press; 2009. Retrieved from http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=12584.

Prior Live Births

he number of prior live births is used as a proxy for parity. Parity is defined by CDC as the number of times a woman has been pregnant for 20 or more weeks regardless of whether the infant is dead or alive at birth. Parity does not include the current pregnancy. MICA reported indicators for Prior Live Births include: 0, 1, 2, 3, and 4+. Data are unavailable for 2009.

Race/Ethnicity

Race and ethnicity information are added on each participant’s Demographics record in MOWINS. This is a required field and should not be blank. MICA reports race data for White, Black/African-American, and All Races on main tables. The expanded race option can be used to view data for the American Indian/Alaska Native, Asian/Native Hawaiian/Pacific Islander, Multiracial, and Unknown categories. In MOWINS no Other categories can be entered except Multiracial. Also, MOWINS does not allow for Unknown race. Hispanic and Non-Hispanic are reported as Ethnicity categories. To view data for combinations of race/ethnic categories, such as White/Non-Hispanic, make the specific race and ethnicity selections as part of your query in the data step of the MICA page or select race and ethnicity as the row and column variables when building your table.

Smoking

All smoking data are self-reported and are assumed to be underreported.

Smoking During Three Months Prior to Pregnancy

This indicator is calculated by comparing the fields Cigarette Usage (Average Number) Per Day – Three Months Prior to Pregnancy and Smoking Change on the Prenatal record.

Smoking During Pregnancy, as of WIC Prenatal Visit

This indicator is calculated from the field Cigarette Usage Per Day – Current, which contains average number of cigarettes currently smoked as recorded on the Prenatal record.

Quit Smoking by First WIC Prenatal Visit

This indicator represents the number of women who smoked during the three months prior to pregnancy but reported that they had stopped smoking as of their first prenatal WIC visit. It is calculated by comparing the field Cigarette Usage Per Day – Current to the fields Cigarette Usage (Average Number) Per Day – Three Months Prior to Pregnancy and Smoking Change on the Prenatal record. The denominator for the quit smoking indicators includes only those mothers who were smoking prepregnancy and have known smoking status as of the WIC prenatal visit.

Smoking During Last Three Months of Pregnancy

This indicator is calculated by comparing the fields Cigarette Usage (Average Number) Per Day – Last 3 Months of Pregnancy and Smoking Change on the Postpartum record. In conjunction with indicators related to smoking prior to pregnancy and smoking at the prenatal visit, it may be used to assess the rate of smoking cessation in pregnancy.

Smoking as of WIC Postpartum Visit

This indicator is calculated from the field Cigarette Usage (Average Number) Per Day – Current on the Postpartum record. It is collected to determine whether the woman smoked after delivery. It may also be used to assess smoking cessation as well as resumption of smoking among women who smoked prior to pregnancy but had quit smoking during pregnancy.

Quit smoking by First WIC Prenatal Visit and Stayed Off Cigarettes Through Delivery and First WIC Postpartum Visit

This indicator is calculated by comparing the fields Cigarette Usage Per Day – Current to the fields Cigarette Usage (Number) Per Day – Three Months Prior to Pregnancy and Smoking Change on the Prenatal record and Cigarette Usage Per Day – Last 3 Months of Pregnancy and Cigarette Usage (Number) Per Day – Current on the Postpartum record. The denominator for the quit smoking indicators includes only those mothers who were smoking prepregnancy.

TANF – Receiving at WIC Visit

The Temporary Assistance for Needy Families (TANF) program is administered by the Missouri Department of Social Services. This program provides temporary assistance to needy families with children. This indicator is a proxy for socioeconomic status and may be used to evaluate the impact of WIC referral services. Data are unavailable for 2009. To learn more about TANF, visit http://www.dss.mo.gov/fsd/tempa.htm.

Term Pregnancy Weight Gain/All Pregnancy Weight Gain

Weight Gained during Pregnancy is entered on the mother’s postpartum record. This is compared to the mother’s prepregnancy BMI category to determine her weight gain classification. (See also definition for Prepregnancy weight/Prepregnancy BMI.) The WIC Postpartum MICA reports two indicators related to maternal weight gain. Term pregnancy weight gain includes full term live births only, which controls for the lower weight gain associated with preterm delivery. Pregnancy weight gain for all live births includes weight gain associated with preterm delivery.

All Pregnancy Weight Gain

All pregnancy weight gain includes weight gain associated with all live births (including preterm delivery).

Term Pregnancy Weight Gain

Term pregnancy weight gain includes full term live births only, which controls for the lower weight gain associated with preterm delivery. The term pregnancy weight gain calculation includes only records with a pregnancy length of 37-48 weeks.

Pregnancy weight gain is considered to be unknown if:

• The prepregnancy weight field is blank or includes a biologically implausible value of less than 22.6796 kg (50 lbs) or more than 226.796185 kg (500 lbs); or
• The prepregnancy height field on is blank or includes a biologically implausible value of less than 101.6 cm (40 inches) or greater than 212.9 cm (83.82 inches).

Recommended Weight Gain Ranges for Singleton Pregnancies (1990 Institute of Medicine)3

• Pregnancy weight gain is considered to be less than ideal if:
• The mother lost weight;
• The mother was underweight prior to pregnancy and gained less than 28 pounds; or
• The mother had a normal weight prior to pregnancy and gained less than 25 pounds; or
• The mother was overweight prior to pregnancy and gained less than 15 pounds; or
• The mother was obese prior to pregnancy and gained less than 11 pounds.
• Pregnancy weight gain is considered to be ideal if:
• The mother was underweight prior to pregnancy and gained between 28 and 40 pounds;
• The mother had a normal weight prior to pregnancy and gained between 25 and 35 pounds; or
• The mother was overweight prior to pregnancy and gained between 15 and 25 pounds;
• The mother was obese prior to pregnancy and gained between 11 and 20 pounds.
• Pregnancy weight gain is considered to be greater than ideal if:
• The mother was underweight prior to pregnancy and gained more than 40 pounds; or
• The mother had a normal weight prior to pregnancy and gained more than 35 pounds; or
• The mother was overweight prior to pregnancy and gained more than 25 pounds; or
• The mother was obese prior to pregnancy and gained more than 20 pounds.

Recommended Weight Gain Ranges for Twin Pregnancies (1990 Institute of Medicine)3

• The IOM does not include weight gain recommendations for underweight women with multiples.
• Pregnancy weight gain is considered to be less than ideal if:
• The mother lost weight; or
• The mother had a normal weight prior to pregnancy and gained less than 37 pounds; or
• The mother was overweight prior to pregnancy and gained less than 31 pounds; or
• The mother was obese prior to pregnancy and gained less than 25 pounds.
• Pregnancy weight gain is considered to be ideal if:
• The mother had a normal weight prior to pregnancy and gained between 37 and 54 pounds; or
• The mother was overweight prior to pregnancy and gained between 31 and 50 pounds; or
• The mother was obese prior to pregnancy and gained between 25 and 42 pounds.
• Pregnancy weight gain is considered to be greater than ideal if:
• The mother had a normal weight prior to pregnancy and gained more than 54 pounds; or
• The mother was overweight prior to pregnancy and gained more than 50 pounds; or
• The mother was obese prior to pregnancy and gained more than 42 pounds.

WIC Prenatal Entry/WIC Enrollment

Trimester in which pregnant woman enrolled in WIC. This indicator is calculated as the difference between the Last Menstrual Period Date and the WIC Start Date.

WIC Enrollment categories use CDC definitions for Low Hematocrit/Low Hemoglobin Trimesters, which begins the calculation of weeks starting with the first day of the last menstrual period:

• 1st trimester: 0-91 days (0-13 weeks)
• 2nd trimester: 92-182 days (14-26 weeks)
• 3rd trimester: 183-336 days (27-48 weeks) – day range extends past 40 weeks to cover postterm pregnancies

WIC Postpartum Entry

This indicator is calculated as the difference between the delivery date and the WIC Start Date.