The Impact of Birth Spacing on Subsequent Feto-Infant Outcomes among Community Enrollees of a Federal Healthy Start Project Hamisu M. Salihu, MD, PhD Euna M. August, MPH Alfred K. Mbah, PhD Raymond de Cuba, II, MPH Amina P. Alio, PhD Vanessa Rowland-Mishkit, RN, BSN, LHRM Estrellita “Lo” Berry, MA

BACKGROUND  The recommended interval, after a live birth, before attempting a subsequent pregnancy, is at least 24 months –Birth-to-pregnancy (BTP) interval = interval between the date of a live birth and the start of the subsequent pregnancy

BACKGROUND: Adverse Outcomes  Preterm birth  Low birth weight  Small size for gestational age  Congenital anomaly  Stillbirth  Neonatal death

PURPOSE  To assess the impact of a Federally-funded Healthy Start program, Central Hillsborough Healthy Start (CHHS), on birth spacing and subsequent birth outcomes –To determine the interpregnancy interval patterns among women in Hillsborough County of Tampa, Florida –To assess racial/ethnic variances in interpregnancy interval patterns within this population

BACKGROUND: CHHS  GOAL: To reduce racial/ethnic disparities in maternal and infant health outcomes among urban populations in Hillsborough County of Tampa, Florida (zip codes: 33602, 33603, 33605, 33607, and 33610) –Operated by REACHUP, a community-based organization –Funded through the Maternal & Child Health Bureau’s Healthy Start Initiative

BACKGROUND: CHHS  Primary provider of pre- and post-natal risk reduction services to residents of the central portion of Hillsborough County  Proven success in reducing adverse birth outcomes –An evaluation found that CHHS services were associated with a 33% reduction in low birth weight and preterm birth

METHODS  Linked CHHS program data with vital statistics records from the Florida Department of Health for years  Analyses were limited to: –Mothers with records on consecutive singleton first and second pregnancies –Mothers who had both pregnancies in the state of Florida

METHODS: Study Criteria Hillsborough County, Florida linked maternal data files ( ) Mothers having both first and second singleton pregnancies = 36,950 Eliminate 109 records of births not considered viable ( 44 weeks gestation) = 36,747 Eliminate 94 records with interpregnancy interval of <0 = 36,856 Eliminate 29 records with missing information for small size for gestational age = 36,718 Records retained for analysis: N = 36,718 (99.4%)

METHODS: Variables  Interpregnancy interval (IPI) = time period between 1 st and 2 nd pregnancy  Gestational age estimated based on the interval between the LMP and the date of child birth

METHODS: Variables  Exposed: IPI<24 months  Unexposed: IPI>24 months  Subgroups: –0-5 months –6-17 months –18-23 months –≥24 months (referent category)

METHODS: Variables  Outcomes of Interest: –Low birth weight (LBW): birth weight less than 2,500 g –Preterm birth (PTB): having a gestational age less than 37 weeks –Small-for-gestational age (SGA): birth weight less than the tenth percentile for gestational age based on the U.S. growth curve. –Composite variable for feto-infant morbidities: occurrence of at least one of the adverse pregnancy outcomes

METHODS: Variables  Race/ethnicity: white, black, Hispanic, and other  Marital status: married or single  Maternal age: <35 years and ≥35 years Educational level: <12 years or ≥12 years  Maternal prenatal smoking: yes or no  Adequacy of prenatal care: adequate or inadequate

METHODS: Variables Common obstetric and medical complications: –Anemia –Insulin dependent diabetes mellitus –Other types of diabetes mellitus –Chronic hypertension –Preeclampsia –Eclampsia –Abruption placenta –Placenta previa –Renal disease –Composite variable

METHODS: Statistical Analysis  Chi-square tests: compare baseline characteristics of mothers by exposure status  Multivariate logistic regression: assess the association between IPI and each of the adverse pregnancy outcomes

RESULTS: Sociodemographics

RESULTS: Adjusted Estimates

DISCUSSION  Very short (IPI<6 months) and long (≥24 months) IPIs result in an increased risk for feto-infant morbidities, including LBW and PTB  No observed increase in risk of SGA for any of the IPI categories  “Maternal depletion syndrome” and IPI

DISCUSSION: Limitations  Low numbers of mothers with an IPI of ≥60 months  Possible overestimation of the risk for feto- infant morbidities for ≥24 months category  Small number of mothers from within the CHHS service area available for analysis  Limited generalizability

DISCUSSION: Strengths  Data for births throughout Hillsborough County, Florida from –Sufficient sample size –Minimizes selection bias –Strengthens power  Controlled for several potential confounders

CONCLUSION  Further evidence of the association between IPI and feto-infant morbidities  Interconception care needs to be prioritized with women prior to subsequent pregnancy  Results were inconclusive regarding the role of Healthy Start  More research is needed

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