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 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

METHODS: Study CriteriaHillsborough County, Florida linked maternal data files (2002-2009)

Mothers having both first and second singleton pregnancies= 36,950

Eliminate 109 records of births not considered viable (<20 weeks gestation and >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 1st and 2nd 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

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 2002-2009– 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

THANK YOU!