Hamisu M. Salihu, MD, PhD Euna M. August, MPH Alfred K. Mbah, PhD Raymond de Cuba, II, MPH

1. 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

2. 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

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

4. 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

5. 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

6. 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

7. METHODS • Linked CHHS program data with vital statistics records from the Florida Department of Health for years 2002-2009 • Analyses were limited to: • Mothers with records on consecutive singleton first and second pregnancies • Mothers who had both pregnancies in the state of Florida

8. METHODS: Study Criteria Hillsborough County, Florida linked maternal data files (2002-2009) Mothers having both first and second singleton pregnancies = 36,950 Eliminate 94 records with interpregnancy interval of <0 = 36,856 Eliminate 109 records of births not considered viable (<20 weeks gestation and >44 weeks gestation) = 36,747 Eliminate 29 records with missing information for small size for gestational age = 36,718 Records retained for analysis: N = 36,718 (99.4%)

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

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

11. 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

12. 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

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

14. 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

15. RESULTS: Sociodemographics

16. RESULTS: Adjusted Estimates

17. RESULTS: Adjusted Estimates

18. 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

19. 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

20. DISCUSSION: Strengths • Data for births throughout Hillsborough County, Florida from 2002-2009 • Sufficient sample size • Minimizes selection bias • Strengthens power • Controlled for several potential confounders

21. 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

22. THANK YOU!