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Sender's message: Obesity & stillbirth search
    
Maternal obesity and risk of stillbirth: a
metaanalysis.
Chu
SY, Kim
SY, Lau
J, Schmid
CH, Dietz
PM, Callaghan
WM, Curtis
KM.
Division of Reproductive Health, Centers for Disease
Control and Prevention, Atlanta, GA 30333, USA. syc1@cdc.gov
We
conducted this metaanalysis to summarize the available epidemiologic evidence
on the relationship between maternal overweight and obesity and the risk of
stillbirth. We identified studies from 3 sources: (1) a PubMed search of
relevant articles that were published between January 1980 and September 2005,
(2) reference lists of publications that were selected from the PubMed search,
and (3) reference lists of review articles on obesity and maternal outcomes
that were published between 2000 and 2005. We used a Bayesian random effects
model to perform the metaanalysis and metaregression. Nine studies were
included in the metaanalysis. The unadjusted odds ratios of a stillbirth were
1.47 (95% CI, 1.08-1.94) and 2.07 (95% CI, 1.59-2.74) among overweight and
obese pregnant women, respectively, compared with normal-weight pregnant
women. The metaregression analysis found no evidence that these estimates were
affected by selected study characteristics. Maternal obesity is associated
with an increased risk of stillbirth, although the mechanisms to explain this
association are not clear.
Publication Types:
PMID: 17826400 [PubMed - indexed for MEDLINE]
-
Comment in:
Extreme
obesity and risk of stillbirth among black and white
gravidas.
Salihu
HM, Dunlop
AL, Hedayatzadeh
M, Alio
AP, Kirby
RS, Alexander
GR.
Department of Epidemiology, University of South Florida,
Tampa, Florida, USA. hamisu.salihu@gmail.com
OBJECTIVE: To estimate the
risk for stillbirth among three generally accepted obesity subtypes based on
severity. METHODS: We used the Missouri maternally linked cohort data
containing births from 1978 to 1997. Using prepregnancy weight and height,
mothers were classified on the basis of calculated body mass index (BMI) above
30 into three subsets: class I (30-34.9), class II (35-39.9), and extreme
obesity (greater than or equal to 40). Using normal-weight, white women
(18.5-24.9) as a reference, we applied Cox proportional hazard regression
models to estimate risks for stillbirth. RESULTS: The prevalence of obesity in
pregnant women was 9.5% (12.8% among blacks and 8.9% among whites). Overall,
obese mothers were about 40% more likely to experience stillbirth compared
with nonobese gravidas (adjusted hazard ratio 1.4; 95% confidence interval
[CI] 1.3-1.5). The risk for stillbirth increased in a dose-dependent fashion
with increase in BMI: class I (adjusted hazard ratio 1.3; 95% CI 1.2-1.4);
class II (adjusted hazard ratio 1.4; 95% CI 1.3-1.6) and extreme obesity
(adjusted hazard ratio 1.9; 95% CI 1.6-2.1; P for trend <.01). Obese black
mothers experienced more stillbirths than their white counterparts (adjusted
hazard ratio 1.9; 95% CI 1.7-2.1 compared with adjusted hazard ratio 1.4; 95%
CI 1.3-1.5). The black disadvantage in stillbirth widened with increase in
BMI, with the greatest difference observed among extremely obese black mothers
(adjusted hazard ratio 2.3; 95% CI 1.8-2.9). CONCLUSION: Obesity is a risk
factor for stillbirth, particularly among extremely obese, black mothers.
Strategies to reduce black-white disparities in birth outcomes should consider
targeting obese, black women. LEVEL OF EVIDENCE: II.
Publication Types:
- Research Support, Non-U.S. Gov't
PMID: 17766599 [PubMed -
indexed for MEDLINE]
-
Comment in:
Interpregnancy weight change and risk of adverse pregnancy
outcomes: a population-based study.
Villamor
E, Cnattingius
S.
Department of Nutrition, Harvard School of Public Health,
Boston, MA 02115, USA. evillamo@hsph.harvard.edu
BACKGROUND: Maternal
obesity has been positively associated with risk of adverse pregnancy
outcomes, but evidence of a causal relation is scarce. Causality would be lent
support if temporal changes in weight affected risk of adverse pregnancy
outcomes. METHODS: We examined the associations between change in prepregnancy
body-mass index (BMI) from the first to the second pregnancies, and the risk
of adverse outcomes during the second pregnancy in a nationwide Swedish study
of 151 025 women who had their first two consecutive singleton births between
1992 and 2001. FINDINGS: Compared with women whose BMI changed between -1.0
and 0.9 units, the adjusted odds ratios for adverse pregnancy outcomes for
those who gained 3 or more units during an average 2 years were: pre-eclampsia, 1.78 (95% CI 1.52-2.08); gestational hypertension 1.76
(1.39-2.23); gestational diabetes 2.09 (1.68-2.61); caesarean delivery 1.32
(1.22-1.44); stillbirth 1.63 (1.20-2.21); and large-for-gestational-age birth
1.87 (1.72-2.04). The associations were linearly related to the amount of
weight change and were also noted in women who had a healthy prepregnancy BMI
for both pregnancies. INTERPRETATION: These findings lend support to a causal
relation between being overweight or obese and risks of adverse pregnancy
outcomes. Additionally they suggest that modest increases in BMI before
pregnancy could result in perinatal complications, even if a woman does not
become overweight. Our results provide robust epidemiological evidence for
advocating weight loss in overweight and obese women who are planning to
become pregnant and, to prevent weight gain before pregnancy in women with
healthy BMIs.
Publication Types:
- Research Support, Non-U.S. Gov't
PMID: 17011943 [PubMed -
indexed for MEDLINE]
-
-
Prepregnancy obesity and fetal death: a
study within the Danish National Birth Cohort.
Nohr
EA, Bech
BH, Davies
MJ, Frydenberg
M, Henriksen
TB, Olsen
J.
Danish Epidemiology Science Centre, Institute of Public
Health, University of Aarhus, Aarhus, Denmark. ean@soci.au.dk
OBJECTIVE: To examine the association between high
prepregnancy body mass index and fetal death, allowing for the effects of
gestational age, weight gain, and maternal diseases in pregnancy. METHODS:
Prepregnancy body mass index (BMI) and fetal death were examined in the Danish
National Birth Cohort among 54,505 pregnant women who participated in a
comprehensive interview during the second trimester. Pregnancy outcomes were
obtained from registers and medical records. Cox regression analyses with
delayed entry and time-dependent covariates were used to estimate the risk of
fetal death. RESULTS: Compared with normal-weight women (18.5 < or = BMI
< 25), the risks of fetal death among obese women (BMI > or = 30),
expressed as adjusted hazard ratios (HRs) and 95% confidence intervals (CIs)
were as follows: before week 14: 0.8 (0.5-1.4), weeks 14-19: 1.6 (1.0-2.5),
weeks 20-27: 1.9 (1.1-3.3), weeks 28-36: 2.1 (1.0-4.4), weeks 37-39: 3.5
(1.9-6.4), and weeks 40+: 4.6 (1.6-13.4). Overweight women (25 < or = BMI
< 30) also experienced a higher risk after 28 weeks, and especially after
40 weeks of gestation (HR 2.9, 95% CI 1.1-7.7). Analysis of stillbirth (fetal
death at 28+ completed weeks of gestation) indicated that the effects were not
due to obesity-related diseases in pregnancy, nor was weight gain associated
with stillbirth. The increased risk of stillbirth among overweight and obese
women was partly attributable to inadequate placental function (crude odds
ratios 2.1, 95% CI 1.0-4.4, and 5.2, 95% CI 2.5-10.9, respectively).
CONCLUSION: Prepregnancy obesity was associated with an increasing excess risk
of fetal death with advancing gestation, and placental dysfunction may be a
possible contributing factor.
Publication Types:
- Comparative Study
- Research Support, Non-U.S. Gov't
PMID: 16055572 [PubMed -
indexed for MEDLINE]
-
Pre-pregnancy weight and the risk of
stillbirth and neonatal death.
Kristensen
J, Vestergaard
M, Wisborg
K, Kesmodel
U, Secher
NJ.
Perinatal Epidemiological Research Unit, Department of
Obstetrics and Gynaecology, Aarhus University Hospital, 8200 Aarhus N,
Denmark.
OBJECTIVE: To evaluate the association between maternal
pre-pregnancy body mass index (BMI) and the risk of stillbirth and neonatal
death and to study the causes of death among the children. DESIGN: Cohort
study of pregnant women receiving routine antenatal care in Aarhus, Denmark.
SETTING: Aarhus University Hospital, Denmark, 1989-1996. POPULATION: A total
of 24,505 singleton pregnancies (112 stillbirths, 75 neonatal deaths) were
included in the analyses. METHODS: Information on maternal pre-pregnancy
weight, height, lifestyle factors and obstetric risk factors were obtained
from self-administered questionnaires and hospital files. We classified the
population according to pre-pregnancy BMI as underweight (BMI <18.5
kg/m(2)), normal weight (BMI 18.5-24.9 kg/m(2)), overweight (BMI 25-29.9
kg/m(2)) and obese (BMI 30.0 kg/m(2) or more). MAIN OUTCOME MEASURES:
Stillbirth and neonatal death and causes of death. RESULTS: Maternal obesity
was associated with a more than doubled risk of stillbirth (odds ratio = 2.8,
95% confidence interval [CI]: 1.5-5.3) and neonatal death (odds ratio = 2.6,
95% CI: 1.2-5.8) compared with women of normal weight. No statistically
significantly increased risk of stillbirth or neonatal death was found among
underweight or overweight women. Adjustment for maternal cigarette smoking,
alcohol and caffeine intake, maternal age, height, parity, gender of the
child, years of schooling, working status and cohabitation with partner did
not change the conclusions, nor did exclusion of women with hypertensive
disorders or diabetes mellitus. No single cause of death explained the higher
mortality in children of obese women, but more stillbirths were caused by
unexplained intrauterine death and fetoplacental dysfunction among obese women
compared with normal weight women. CONCLUSION: Maternal obesity more than
doubled the risk of stillbirth and neonatal death in our study. The present
and other studies linking maternal obesity to an increased risk of severe
adverse pregnancy outcomes emphasise the need for public interventions to
prevent obesity in young women.
Publication Types:
- Research Support, Non-U.S. Gov't
PMID: 15777435 [PubMed -
indexed for MEDLINE]
-
-
Maternal morbid obesity and the risk of
adverse pregnancy outcome.
Cedergren
MI.
Division of Obstetrics and Gynecology, Department of
Molecular and Clinical Medicine, Faculty of Health Sciences, Linköping
University, SE-581 85 Linköping, Sweden. marie.cedergren@lio.se
OBJECTIVE: To evaluate whether morbidly obese
women have an increased risk of pregnancy complications and adverse perinatal
outcomes. METHODS: In a prospective population-based cohort study, 3,480 women
with morbid obesity, defined as a body mass index (BMI) more than 40, and
12,698 women with a BMI between 35.1 and 40 were compared with normal-weight
women (BMI 19.8-26). The perinatal outcome of singletons born to women without
insulin-dependent diabetes mellitus was evaluated after suitable adjustments.
RESULTS: In the group of morbidly obese mothers (BMI greater than 40) as
compared with the normal-weight mothers, there was an increased risk of the
following outcomes (adjusted odds ratio; 95% confidence interval):
preeclampsia (4.82; 4.04, 5.74), antepartum stillbirth (2.79; 1.94, 4.02),
cesarean delivery (2.69; 2.49, 2.90), instrumental delivery (1.34; 1.16,
1.56), shoulder dystocia (3.14; 1.86, 5.31), meconium aspiration (2.85; 1.60,
5.07), fetal distress (2.52; 2.12, 2.99), early neonatal death (3.41; 2.07,
5.63), and large-for-gestational age (3.82; 3.50, 4.16). The associations were
similar for women with BMIs between 35.1 and 40 but to a lesser degree.
CONCLUSION: Maternal morbid obesity in early pregnancy is strongly associated
with a number of pregnancy complications and perinatal conditions. LEVEL OF
EVIDENCE: II-2
Publication Types:
- Research Support, Non-U.S. Gov't
PMID: 14754687 [PubMed -
indexed for MEDLINE]
-
-
Trends in smoking and overweight during
pregnancy: prevalence, risks of pregnancy complications, and adverse pregnancy
outcomes.
Cnattingius
S, Lambe
M.
Department of Medical Epidemiology, Karolinska Institutet,
Stockholm, Sweden. Sven.Cnattingius@mep.ki.se
The prevalence of smoking
during pregnancy is decreasing in some, but not all, developed countries, as
the prevalence of overweight is increasing rapidly in most countries. During
pregnancy, smoking increases the risk of placental abruption, but reduces the
risk of preeclampsia, while overweight increases the risks of gestational
diabetes, preeclampsia, and cesarean delivery. Both smoking and overweight are
associated with dose-dependent increases in risks of stillbirth and very
preterm birth (< 32 weeks). From a public health perspective, smoking and
overweight today probably represent the most important modifiable risk factors
for pregnancy complications and adverse pregnancy outcomes.
Publication
Types:
- Research Support, Non-U.S. Gov't
PMID: 12211619 [PubMed -
indexed for MEDLINE]
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