Unit 4 DB: The Patient Protection and Affordable Care Act: How it Affects Healthcare Decisions and Outcomes

Please use  7th edition of the APA for references (use attached peer-reviewed article) 

Primary Task Response: Within the Discussion Board area, write 400–600 words that respond to the following questions with your thoughts, ideas, and comments. This will be the foundation for future discussions by your classmates. Be substantive and clear, and use examples to reinforce your ideas.

Locate a recent peer-reviewed article from a healthcare journal that reports on how well the Patient Protection and Affordable Care Act (PPACA) is working. 

Provide an analysis of whether or not you agree with the author of this article, and assess what can be learned from past health reform efforts that can help improve the U.S health system in the future.

Peer reviewed article: https://www.proquest.com/docview/2468946144/abstract?accountid=144789&parentSessionId=6kahSSB6NSlVsvWvP9MzRpxQtYQ5l5o7djfyDRyG1h4%3D&pq-origsite=summon&sourcetype=Scholarly%20Journals

Medicaid expansion and infant mortality: the
(questionable) impact of the Affordable Care Act
Amanda Cook ,1 Amanda Stype 2

ABSTRACT
Background Many states expanded Medicaid eligibility
under the Patient Protection and Affordable Care Act
(PPACA). Medicaid expansion might impact infant
mortality through improved maternal health prior to
pregnancy and reduced insurance churn. Some studies
suggest the PPACA had no significant impact on low birth
weight or preterm birth, while others suggest that the
PPACA led to a significant decrease in infant mortality.
Methods Using a difference-in-differences estimator
with fixed effects to control for differences in state
characteristics and time trends we analyse three samples
of births from the CDC’s linked birth/death files from 2011
to 2017 to estimate the impact of Medicaid expansion on
infant mortality.
Results We find mixed results. In our full sample, we
find no statistically significant change in infant mortality
associated with PPACA Medicaid expansion. However,
when we restrict the sample to states who had adopted
the 2003 birth certificate form and when we further
exclude states with a Medicaid waiver, in both samples
we see reductions in infant mortality for babies born to
mothers of all races. When we stratify by race, we find
infant mortality decreased for babies born to white
mothers. However, this decrease is not seen for babies
born to black mothers.
Conclusions Medicaid expansion under the PPACA has
an impact on infant mortality, but the results are sensitive
to the sample of states included in the study. There is
suggestive evidence that Medicaid expansion is not
closing the infant mortality gap between black and white
babies.

INTRODUCTION

The 2018 infant mortality rate in the USA of 5.9
deaths per 1000 live births was higher than many
other developed countries. Among OECD coun-
tries, the USA was 33rd out of 36 (with only
Mexico, Turkey and Chile having a higher rate).1

Furthermore, there are large racial disparities in
infant mortality in the USA. According to the
Centers for Disease Control (CDC), babies born to
African American mothers in 2017 in the USA were
2.3 times more likely to die as infants than babies
born to white non-Hispanic mothers. The high
infant mortality rate in the USA, as well as racial
inequalities in infant mortality rates and infant
health is of concern.

The relationship between various interventions
and infant mortality has been extensively explored.
Medical professionals and policy makers have exam-
ined the impact of interventions on infant mortality.
In both the public health and economics literature,
researchers have studied the relationship between

insurance, specifically Medicaid, and infant
mortality.2 3 Recently, Medicaid expanded in some
states under the Patient Protection and Affordable
Care Act (PPACA). Prior to the expansion, federal
rules only required states to provide Medicaid to
individuals who earned below a certain income and
who were in certain categorical groups, for example,
individuals with disabilities. With Medicaid expan-
sion, states had the option with the help of a subsidy
from the federal government, to increase Medicaid
eligibility to include anyone earning less than 138%
of the Federal Poverty Line (FPL). Researchers have
attempted to examine the relationship between
PPACA-related Medicaid expansion and infant mor-
tality and perinatal health outcomes such as low
birth weight and preterm birth.4–7 One might expect
that more generous eligibility requirements for pub-
licly provided health insurance (Medicaid) may lead
to a decrease in infant mortality as well as fewer
poor perinatal health outcomes. Expansion of
Medicaid would lead more women who were pre-
viously uninsured or underinsured to have afford-
able access to care before pregnancy. This may lead
to better health for both mother and baby, as
a mother may start her pregnancy with fewer or
better controlled underlying conditions. Medicaid
expansion reduces ‘insurance churn’ among
mothers.8 Uncertainty about what is covered by
insurance, which is exacerbated by switching insur-
ance, may cause women to postpone care.

Bhatt and Beck-Sagué examine the difference in
mean infant mortality rates before and after
Medicaid expansion overall and by racial and ethnic
subgroups. While they measure differences between
groups and across time, their analysis does not deter-
mine the statistical significance of these differences.4

In a letter of response to Bhatt and Beck-Sagué,
Mallinson et al raise two primary concerns: (1) var-
iation in timing of Medicaid expansion and (2) time
trends in infant mortality.5

Brown et al use a difference-in-differences estima-
tor to examine the impact ofMedicaid expansion on
low birth weight and preterm birth, both of which
can be precursors to infant mortality.6 They find no
statistically significant impact of Medicaid expan-
sion on low birth weight or preterm birth overall,
but find a decrease in incidence in low birth weight
and preterm births for black infants in states that
expanded Medicaid, and therefore a decrease in
perinatal health disparities for black babies.

METHODS

This paper revisits the impact of PPACA Medicaid
expansion on infant mortality. Our study design and

Original research

10 Cook A, Stype A. J Epidemiol Community Health 2021;75:10–15. doi:10.1136/jech-2019-213666

To cite: Cook A, Stype A. J
Epidemiol Community Health
2021;75:10–15.

1Economics, Bowling Green
State University, Bowling Green,
Ohio, USA
2Economics, Eastern Michigan
University, Ypsilanti,
Michigan, USA.

Correspondence to
Amanda Cook, Economics,
Bowling Green State
University, Bowling Green, OH
43404, USA;
accook@ bgsu. edu

Received 18 December 2019
Revised 17 July 2020
Accepted 11 August 2020
Published Online First
10 September 2020

Original research

© Author(s) (or their
employer(s)) 2021. No
commercial re-use. See
rights and permissions.
Published by BMJ.

mailto:accook@bgsu.edu

mailto:accook@bgsu.edu

http://crossmark.crossref.org/dialog/?doi=10.1136/jech-2019-213666&domain=pdf

http://orcid.org/0000-0002-8702-443X

http://orcid.org/0000-0002-9004-9240

methodology address both of Mallinson et al’s concerns and
employ amethodology similar to Brown et al.To address variation
in timing of Medicaid expansion, we restrict our sample to states
and theDistrict of Columbia that expandedMedicaid eligibility on
January 1, 2014 and compare them to states that had not
expanded Medicaid as of May 1, 2019. In our difference-in-
differences analysis, we include time trends to account for national
changes in infant mortality. We also control for time-invariant
state characteristics. Our strategy allows us to examine any impact
of the PPACA Medicaid expansion on infant mortality separately
from national trends or any differences that arise between states
that are constant across time. Because of the large racial differ-
ences in infant mortality rates, we also study the impact of
Medicaid expansion on infant mortality separately for babies
born to black mothers and babies born to white mothers.

Study population
We combine CDC linked birth/infant death annual data from
2011 to 2017 with Medicaid expansion data by state-year.9 The
linked birth/infant death records include all live births for the 50
states, the District of Columbia, Puerto Rico and Guam. Our
study period begins in 2011 to include mothers who conceived
after the beginning of the PPACA inMarch 2010 and to avoid the
implementation of earlier PPACA policy changes such as the
young adult provision and increased access to birth control.

We consider three samples. In the first sample, the treatment
group is 24 states and the District of Columbia that expanded
Medicaid on January 1, 2014. The control group is the 12 states
yet to expand Medicaid as of May 1, 2019. The state groups are
in table 1. States that expanded Medicaid after January 2014,
Puerto Rico and Guam are excluded from our sample.

A new form for US birth certificates was adopted in 2003;
however, it took until mid-2015 for all 50 states and territories
to adopt this form.10 11 This new form slightly modified ques-
tions relating to race and education. Our second sample is states
who had adopted the new form by January 1, 2011.12 These
states uniformly use the new form after 2011. Table 1 denotes
states excluded from this second sample with asterisks. Our third
sample excludes states that had a Section 1115 waiver for
Medicaid expansion (Iowa and Kentucky).

In our analysis, we control for mother’s level of education, race
and marital status. We use the variable ‘Mother’s Bridged Race
Categories’ for the years 2011–2016 and ‘Mother’s Single Race
Groups’ for 2017, due to a change in race reporting. We use the
Stata command ‘expand’ to turn the demographic-group-state-
year level of observation into a sample in which an observation is
a birth, and associated demographic characteristics of the mother,
which occurred in a treated or control state between 2011 and
2017.

Summary statistics for expansion and non-expansion states for
each sample are in table 2. In table 3, we stratify summary
statistics by race for our third and preferred sample.

Statistical analysis
We estimate the following equations using STATA SE version 15
(StataCorp)

Infant Mortality Rates;y;d ¼ �0 þ �1Treateds;y þ �s þ �y

þ Xs;y;d� þ “s;y;d
ð1Þ

where Treated is an indicator variable equal to 1 if the
mother gave birth after the implementation of PPACA
Medicaid expansion (January 1, 2014) in a state that expanded

Medicaid. X is a set of maternal demographic controls includ-
ing maternal race, level of education, age category and marital
status. These factors are correlated with birth outcomes.13–16

We include them to separately identify the impact of Medicaid
expansion from these characteristics. �s and �t are state-fixed
and time-fixed effects, respectively. State-fixed effects capture
all details specific to the state of birth which are time invar-
iant, for example, healthcare infrastructure, differences in
racial composition, state-specific policies which might influ-
ence birth outcomes, take up of the young adult provision and
any other unobservable differences between states. The time-
fixed effects to control for national time trends which might
impact infant mortality like access to birth control, changing
attitudes towards motherhood and the decision to delay ferti-
lity because of a challenging economic environment. If there
are comprehensive, country-wide efforts to reduce infant mor-
tality which are successful, time-fixed effects allow us to
separately identify any impact of the ACA’s Medicaid expan-
sion on infant mortality from a year by year decline in
national infant mortality rates. We cluster SEs at the state
level to reflect that states across time are not independent
observations.

Our coefficient of interest, �1, determines if there is
a statistically significant change in infant mortality in states that
expanded Medicaid compared with states that did not expand
Medicaid.

To examine differential impacts by race, we estimate the fol-
lowing equation to determine if there is a difference in impact of
expansion on infants born to white and black mothers.

Table 1 State groupings

Expansion states Non-expansion states

Arizona† Alabama†

Arkansas† Florida

California Georgia

Colorado Kansas

Connecticut† North Carolina

Delaware Oklahoma

District of Columbia South Carolina

Hawaii† South Dakota

Illinois Tennessee

Iowa Texas

Kentucky Wisconsin

Maryland Wyoming

Massachusetts

Minnesota

Nevada

New Jersey†

New Mexico

New York

North Dakota

Ohio

Oregon

Rhode Island†

Vermont

Washington

West Virginia†

†Indicates states that had not adopted the 2003 birth certificate form prior to the beginning
of our study.

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11Cook A, Stype A. J Epidemiol Community Health 2021;75:10–15. doi:10.1136/jech-2019-213666

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Infant Mortality Rates;y;d ¼ �0 þ �1Treated*whites;y
þ �2Treated*blacks;y þ �s þ �y
þ Xs;y;d*� þ “s;y;d ð2Þ

where Treated �white is an indicator variable equal to 1 if
a white mother gave birth after the implementation of Medicaid
expansion in a state in our sample that expanded Medicaid and
Treated � black is similarly defined for black mothers. Again,
�s and �t are state-fixed effects and time-fixed effects, respec-
tively, and X is a set of maternal demographic variable defined
above.

In equation 2, our coefficients of interest are �1 and �2,
which determine if there is a statistically significant change
in infant mortality for babies born to white mothers or black
mothers after January 1, 2014 in states that expanded
Medicaid compared with non-expansion states. Finally, an
F-test determines if the difference in changes to infant mor-
tality between white and black mothers is statistically sig-
nificant. This result suggests if Medicaid expansion is
closing or exacerbating the infant mortality gap between
babies born to black mothers and babies born to white
mothers.

RESULTS

Column 1 of table 4 displays estimates of the coefficient �1 from
equation (1). For our full sample, we estimate a reduction in
infant mortality of −0.192 per 1000 live births, but it is not

statistically distinguishable from zero. In column 2, we estimate
equation (2) for the full sample to separately estimate the impact
of treatment on babies born to white and black mothers. Again,
we find results that are not statistically distinguishable from zero.
An F-test determines there is no statistically significant differen-
tial impact of Medicaid expansion on infant mortality for babies
born to white and black mothers. This full sample suggests that
Medicaid expansion under the ACA had no measurable impact
on infant mortality for the population as a whole, for babies born
to white mothers, or for babies born to black mothers.

In column 3, we estimate equation (1) for the sample of states
that had adopted the 2003 birth certificate by the start of the
study period. We estimate a reduction of −0.263 (95% CI=
−0.51 to −0.011) in the infant mortality rate for babies born to
mothers of all races. Estimating equation (2) for this sample, we
find that there is a reduction in the infant mortality rate of
−0.277 (90% CI=−0.52 to −0.038) for babies born to white
mothers in expansion states. There is no statistically significant
impact of expansion for babies born to black mothers in expan-
sion states, but the estimated coefficient is positive whereas it is
negative for white mothers.

In our third sample, we include the states which had adopted
the 2003 birth certificate but exclude states that had a Section
1115 waiver (Iowa and Kentucky). Table 4, column 5, estimates
equation (1) for this sample. Again, we observe a reduction in the
infant mortality rate of−0.271 (95% CI=−0.53 to−0.016) for
mothers of all races. Column 6 estimates equation (2). Babies

Table 2 Summary statistics for expansion and non-expansion states for the three samples

(1)
Full
non-exp

(2)
Full
expansion

(3)
Birth cert.
non-exp

(4)
Birth cert.
expansion

(5)
Birth cert. and waiver
non-exp

(6)
Birth cert. and
waiver exp

Mean Mean

Mean Mean Mean Mean

Infant mortality rate (per 1000 live births) 6.23 5.27 6.21 5.30 6.20 5.22

8th grade or less 0.01 0.01 0.02 0.01 0.02 0.02

9–12 grade: no diploma 0.12 0.09 0.14 0.10 0.14 0.10

High school grad (GED) 0.29 0.28 0.33 0.31 0.33 0.30

Some college no degree 0.20 0.20 0.23 0.23 0.23 0.23

Associates degree 0.03 0.03 0.03 0.03 0.03 0.03

Bachelor’s degree 0.16 0.21 0.19 0.22 0.18 0.22

Master’s degree 0.04 0.07 0.04 0.08 0.04 0.08

Doctorate 0.00 0.00 0.00 0.00 0.00 0.00

Education excluded 0.16 0.09 0.02 0.00 0.02 0.00

Education unknown 0.00 0.01 0.00 0.02 0.00 0.02

Age of mother 15–19 0.08 0.05 0.08 0.05 0.08 0.05

Age of mother 20–24 0.28 0.23 0.29 0.23 0.29 0.22

Age of mother 25–29 0.31 0.30 0.31 0.30 0.31 0.30

Age of mother 30–34 0.25 0.32 0.25 0.31 0.25 0.32

Age of mother 35–39 0.08 0.10 0.07 0.11 0.07 0.11

Age of mother 40–44 0.00 0.00 0.00 0.00 0.00 0.00

Married 0.55 0.59 0.54 0.59 0.54 0.59

Unmarried 0.45 0.41 0.46 0.41 0.46 0.41

American Indian or Alaska Native 0.00 0.00 0.00 0.00 0.00 0.00

Black 0.16 0.10 0.16 0.10 0.16 0.10

White 0.82 0.86 0.83 0.86 0.82 0.86

Asian or Pacific Islander 0.02 0.04 0.02 0.04 0.02 0.04

Observations 8 905 591 3 318 206 7 550 372 2 724 464 7 464 931 2 615 357

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12 Cook A, Stype A. J Epidemiol Community Health 2021;75:10–15. doi:10.1136/jech-2019-213666

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born to white mothers in expansion states had a reduction of
−0.288 (90% CI=−0.53 to −0.042) in their infant mortality
rate. However, there was not a statistically significant impact on
infant mortality for babies born to black mothers in expansion
states. In both the second and third sample, an F-test shows that
there is no statistically significant difference between the coeffi-
cients for white and black mothers.

Our results are sensitive to the selection of sample states. In
both the second (birth certificates) and third (waiver exclusion)

samples, we find a statistically significant reduction in infant
mortality among babies born to all women and white women in
expansion states but no statistically significant difference in
infant mortality rates between babies born to white mothers
and babies born to black mothers in expansion states.

DISCUSSION

While the PPACA provides a compelling natural experiment,
some issues need to be considered when examining the impact
of Medicaid expansion on infant mortality and perinatal health
outcomes. The first is selection into Medicaid expansion.
The second is understanding the mechanism through which
Medicaid expansion may impact infant mortality. The third is
other contemporaneous policy changes that may impact insur-
ance and healthcare access.

Bhatt and Beck-Sagué4 acknowledge concerns with selection
into Medicaid expansion and regional heterogeneity. States that
elected to expand Medicaid were states with lower infant mor-
tality rates prior to the reform. Figure 1 illustrates a substantial
difference in the level of infant mortality rates between expan-
sion states and non-expansion states. Furthermore, many of the
states that rejected Medicaid expansion are located in the
Southern USA, which may have worse population health.
However, our state-fixed effects help separately identify state-
specific effects from Medicaid expansion.

Prior to the enactment of the PPACA, pregnant women with
incomes up to 133% of the FPL were already a federally man-
dated group and therefore eligible for coverage at this income
level in all states. While Medicaid expansion has no direct impact
on insurance eligibility for low-income pregnant women during
pregnancy, a potential mechanism for improved health is
increased affordability of health services prior to pregnancy due
to enrollment in Medicaid based solely on income. Clapp et al
find that in states that expanded Medicaid, more births were
covered by Medicaid after expansion. In states that did not
expandMedicaid, mothers still had increased insurance coverage
compared with before the PPACA. These mothers were insured
through private insurance or another payer.7 While this suggests
that there was very little difference in insurance coverage for
pregnant women at the time of birth regardless of residence in
an expansion or non-expansion state, there may still be large
differences in out-of-pocket costs depending on insurance type.

Lower-income women have better access to health insurance
prior to pregnancy in states that expanded Medicaid compared

Table 3 Summary statistics for maternal characteristics for live
births to white and black mothers (2011–2017) 2003 birth certificate
states, excluding states with waivers

(1) (2) (3) (4)
Black non-
expansion

White non-
expansion

Black
expansion

White
expansion

Mean Mean Mean Mean

Infant mortality rate (per
1000 live births)

11.545 5.407 11.589 4.668

Expansion state 0.000 0.000 0.534 0.524

8th grade or less 0.000 0.015 0.000 0.025

9–12 grade: no diploma 0.157 0.130 0.212 0.117

High school grad (GED) 0.460 0.323 0.430 0.290

Some college no degree 0.303 0.222 0.339 0.218

Associates degree 0.005 0.032 0.001 0.038

Bachelor’s degree 0.035 0.209 0.016 0.212

Master’s degree 0.001 0.035 0.001 0.083

Doctorate 0.000 0.000 0.000 0.001

Education excluded 0.037 0.033 0.000 0.000

Education unknown 0.001 0.000 0.001 0.016

Age of mother 15–19 0.124 0.076 0.132 0.058

Age of mother 20–24 0.439 0.272 0.449 0.217

Age of mother 25–29 0.284 0.323 0.282 0.302

Age of mother 30–34 0.137 0.255 0.130 0.308

Age of mother 35–39 0.016 0.072 0.006 0.109

Age of mother 40–44 0.000 0.002 0.000 0.005

Married 0.126 0.614 0.020 0.634

Unmarried 0.874 0.386 0.980 0.366

Observations 955 684 4 128 670 506 697 4 266 566

The level of observation is a birth by a woman living in a state which expanded Medicaid on
January 1, 2014 or in a state which had not expanded Medicaid by May 2019. In column (1),
12.4% of babies were born to black mothers aged 15–19 in non-expansion states.

Table 4 Impact on infant mortality of giving birth in a medicaid expansion state after medicaid expansion

Full sample Birth certificate sample Birth certificate and exclude waiver sample

(1) (2) (3) (4) (5) (6)
All White and black All White and black All White and black

Treated −0.192 −0.263‡ −0.271‡

(0.116) (0.121) (0.122)

Treated_white −0.205 −0.277† −0.288†

(0.125) (0.139) (0.143)

Treated_black 0.370 0.354 0.349

(0.317) (0.381) (0.383)

N 12 223 793 12 223 793 10 274 832 10 274 832 10 080 284 10 080 284

†p<0.10. ‡p<0.05. SEs in parentheses. Difference-in-differences analysis including mother characteristics (race, age, and education of mother). SEs are clustered at the state level. The level of observation is a birth for a mother in our sample.

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13Cook A, Stype A. J Epidemiol Community Health 2021;75:10–15. doi:10.1136/jech-2019-213666

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with those that did not. As a result, it is possible that women
in expansion states may enter pregnancy in better health and
with better controlled chronic conditions. Pregnant women
may also receive prenatal care earlier if they are already
insured, although existing literature has not found this to be
the case.7 There is also less insurance churn among mothers in
expansion states.8 This decreases the bureaucratic hurdles that
a woman must face to receive care both before pregnancy and
early on in pregnancy. Women are better able to maintain
coverage between pregnancies in states that expanded
Medicaid. Mothers who reside in non-expansion states are
more likely to lose insurance coverage in the year after birth
than those who are in expansion states.17

The young adult provision of the PPACA was enacted in
September 2010 in all states and territories and allows adult chil-
dren under the age of 26 to remain on their parents’ employer-
provided insurance. This provision impacted the insurance options
of somemothers before, during, and after pregnancy. It dispropor-
tionately impacts younger mothers who are from families with
higher socioeconomic status.18 It also impacts fertility decisions
of younger women in our sample.19 Because the implementation
of this provision occurred prior to the start of our study period and
state-fixed effects absorb the average young adult provision uptake
by state, the young adult provision does not confound our results.

Policy changes to Medicaid eligibility for pregnant women on
January 1, 2014 would confound our results. After review of
Kaiser Family Foundation’s Annual Updates on Eligibility Rules,
Enrollment and Renewal Procedures, and Cost-Sharing Practices
in Medicaid and CHIP, from November 2013 and January 2015,
the only contemporaneous policy changes occurred in Oklahoma
and Virginia.20 21 Virginia is omitted from all samples and
Oklahoma is part of the control group. Rerunning the model
excluding Oklahoma does not substantively alter the results.

CONCLUSIONS

Insurance access, both before and during pregnancy, is thought to
improve maternal and infant health outcomes. Prior to the PPACA,
pregnant women were eligible forMedicaid at higher income levels
than other groups. As such, there was limited ‘bite’ to the reform for
pregnant women in expansion states. After the PPACA, low-income
women in expansion states have access to health insurance regard-
less of their pregnancy status. This should lead to better control of
underlying conditions and improved overall health, easier access to
early prenatal care, and reduce uncertainty about insurance cover-
age as women become mothers and after they give birth.

Our results vary depending on which sample of states we use.
In our full sample, we find no statistically significant impact of
Medicaid expansion on infant mortality for the whole popula-
tion, babies born to white women, or babies born to black
women. However, when we focus on two samples of states that
implemented the 2003 birth certificates and further exclude
states on a Medicaid waiver, we find reductions in infant mortal-
ity for all mothers and white mothers. It is worth noting, that
while not statistically significant, babies born to black mothers
have an increased risk of infant mortality post-expansion in
expansion states. While large SEs on our estimates for black
mothers mean that we cannot say definitively that the healthcare
landscape is worse for babies born to black mothers, we would be
remiss not tomention that there is suggestive evidence that babies
born to black and white mothers have differential risks of infant
mortality. Furthermore, we find no evidence that Medicaid
expansion lessens the gap in infant mortality rate between babies
born to black mothers and babies born to white mothers.

In contrast to previous studies, our study suggests that changes
in infant mortality rates pre-expansion and post-expansion are
conditional on sample selection of Medicaid expansion states.
This paper solely examines Medicaid expansion, and does not

Figure 1 Infant mortality rates by expansion and non-expansion states: birth certificate and medicaid waiver sample.

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14 Cook A, Stype A. J Epidemiol Community Health 2021;75:10–15. doi:10.1136/jech-2019-213666

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consider other provisions of the PPACA that may have impacted
maternal and infant health, such as reduced-cost birth control.
Our sample period starts after the implementation of many of
these national policies, and thus we can isolate the impact of
Medicaid expansion, while having a uniform environment for
other maternal health initiatives as part of the PPACA. However,
these earlier initiatives may have had impacts on maternal and
infant health and should be considered in future research.

Contributors

AC wrote the statistical analysis plan, cleaned and analysed the data
and drafted and revised the paper. AS analysed previous literature, drafted and
revised the paper.

Funding

The authors have not declared a specific grant for this research from any
funding agency in the public, commercial or not-for-profit sectors.

Competing interests

None declared.

Patient consent for publication

Not required.

Provenance and peer review

Not commissioned; externally peer reviewed.

Data availability statement

Data are available in a public, open access repository.

ORCID iDs

Amanda Cook http://orcid.org/0000-0002-8702-443X
Amanda Stype http://orcid.org/0000-0002-9004-9240

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What is already known on this subject

► Infant mortality in the USA has been declining in the past decade.
Previous work examined the impact of Medicaid expansion under
the Patient Protection and Affordable Care Act. Previous studies
have identified a change in infant mortality rates around
implementation of the PPACA. Other studies, using a difference-in
-difference methodology, have found no significant change in
overall incidence of low birth weight babies or preterm birth, but
a decrease in racial health disparities among babies born to
mothers in states that expanded Medicaid.

What this study adds

► Controlling for differences in state characteristics and falling infant
mortality rates, we use statistical analysis to determine the impact of
the Patient Protection and Affordable Care Act’s Medicaid expansion
on infant mortality and find no statistically significant change in infant
mortality rates when we consider the full sample of expansion and
non-expansion states. In our full sample, differences in infantmortality
rates are predicted by maternal characteristics as well as state
and year effects, not expansion status. Our results depend on the
sample of states. When we restrict our sample to states with
consistent birth certificate reporting and Medicaid waivers, we find
a decrease in infant mortality for babies born to mothers of all races,
but larger reductions for babies born towhite women. This decrease is
not seen for babies born to black mothers and there is no statistically
significant difference between races. This is suggestive evidence that
Medicaid expansion is not closing the infant mortality gap between
babies born to black mothers and babies born to white mothers.

Original research

15Cook A, Stype A. J Epidemiol Community Health 2021;75:10–15. doi:10.1136/jech-2019-213666

Original research

http://orcid.org/0000-0002-8702-443X

http://orcid.org/0000-0002-9004-9240

https://assets.americashealthrankings.org/app/uploads/2018ahrannual_020419

https://assets.americashealthrankings.org/app/uploads/2018ahrannual_020419

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https://www.cdc.gov/nchs/nvss/revisions-of-the-us-standard-certificatesand-reports.htm

https://blogs.cdc.gov/inside-nchs/2014/07/30/the-birth-certificate-finally-goes-national/date

https://blogs.cdc.gov/inside-nchs/2014/07/30/the-birth-certificate-finally-goes-national/date

https://ftp.cdc.gov/pub/health_statistics/nchs/dataset_documentation/DVS/natality/UserGuide2011

https://ftp.cdc.gov/pub/health_statistics/nchs/dataset_documentation/DVS/natality/UserGuide2011

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https://doi.org/10.1007/s00148-017-0676-6

https://www.kff.org/wp-content/uploads/2013/11/8516-getting-into-gear-for-2014-shifting-new-medicaid-eligibility1

https://www.kff.org/wp-content/uploads/2013/11/8516-getting-into-gear-for-2014-shifting-new-medicaid-eligibility1

http://files.kff.org/attachment/report-modern-era-medicaid-findings-from-a-50-state-survey-of-eligibility-enrollment-renewal-and-cost-sharing-policies-in-medicaid-and-chip-as-of-january-2015

http://files.kff.org/attachment/report-modern-era-medicaid-findings-from-a-50-state-survey-of-eligibility-enrollment-renewal-and-cost-sharing-policies-in-medicaid-and-chip-as-of-january-2015

http://files.kff.org/attachment/report-modern-era-medicaid-findings-from-a-50-state-survey-of-eligibility-enrollment-renewal-and-cost-sharing-policies-in-medicaid-and-chip-as-of-january-2015

© 2021 Author(s) (or their employer(s)) 2021. No commercial re-use. See
rights and permissions. Published by BMJ.

INTRODUCTION

METHODS

Study population

Statistical analysis

RESULTS

DISCUSSION

CONCLUSIONS

Contributors

Funding

Competing interests

Patient consent for publication

Provenance and peer review

Data availability statement

ORCID iDs

REFERENCES