13. Perinatal Factors
This section of the Guidelines provides recommendations to pediatric care providers
on management of perinatal factors that predispose children to accelerated atherosclerosis.
The section begins with background information on the role of pediatric care providers
in perinatal risk exposure and the decision to focus on maternal smoking cessation.
This is followed by the Expert Panel's summary of the evidence review. The evidence
review and the development process for the Guidelines are outlined in Section I.
Introduction and are described in detail in Appendix A. Methodology. As described,
the evidence review augments a standard systematic review, whereby the findings
from the studies reviewed constitute the only basis for recommendations, with each
study described in detail. This evidence review combines a systematic review with
an Expert Panel consensus process that incorporates and grades the quality of all
relevant data based on preidentified criteria. Because of the large volume of the
included studies and the diverse nature of the evidence, the Expert Panel also provides
a critical overview of the studies for each risk factor, highlighting those that,
in its view, provide the most important information. Detailed information from each
study has been extracted into the evidence tables, which will be available at http://www.nhlbi.nih.gov/guidelines/cvd_ped/index.htm.
This section ends with the conclusions of the review, grading of the evidence, and
the recommendations. Where evidence is inadequate, the recommendations are the consensus
opinion of the Expert Panel. References are listed sequentially at the end of the
section, with references from the evidence review identified by unique PubMed identifier
(PMID) number in bold text. Additional references do not include the PMID number.
Increasing evidence links prenatal exposures to adverse health outcomes.
Perinatal cardiovascular (CV) risk reduction is an area in which pediatric care
providers can be effective since they are often the only physicians that a mother
sees between pregnancies. The Expert Panel identified three potential areas for
consideration: maternal obesity, choice of neonatal feeding method, and maternal
smoking cessation. Maternal obesity is associated with gestational diabetes, higher
birth weight, childhood obesity as measured by increased body mass index (BMI),
and increased risk of the metabolic syndrome and type 2 diabetes mellitus (T2DM)
However, the Expert Panel could not identify any prepregnancy or postpartum studies
addressing maternal obesity in a pediatric health care setting, and more general
approaches to preventing or treating obesity in women of reproductive age are beyond
the scope of these Guidelines, which are for pediatric care providers. A detailed
discussion of childhood obesity is the subject of Section X. Overweight and Obesity.
With regard to choice of neonatal feeding method, the CV advantages of breastfeeding
as the primary source of nutrition for infants are reviewed in detail in Section
V. Nutrition and Diet. The evidence review for this section therefore focuses
on maternal smoking cessation.
OVERVIEW OF THE EVIDENCE ON MATERNAL SMOKING CESSATION
Smoking during pregnancy is strongly associated with fetal growth retardation. Epidemiologic
studies show that lower birth weight is associated with central adiposity, insulin
resistance, hypertension, T2DM, and increased risk of coronary heart disease decades
later., In most of these
studies, lower birth weight probably represents reduced fetal growth rather than
shorter gestational duration, although some recent studies suggest that preterm
birth also is associated with these adverse outcomes. Among pregnant women who smoke,
the rate of low birth weight increases directly as the number of cigarettes/day
increases. Despite decades of knowledge of its adverse health effects, cigarette
smoking remains common among women of childbearing age, reported at 2223 percent
in 2000, although rates are lower during pregnancy in the United States and other
developed countries. Perhaps paradoxically, maternal smoking during pregnancy is
associated with increased rates of subsequent obesity in offspring and, in some
studies, elevated blood pressure (BP). A recent meta-analysis of observational studies
estimated a pooled odds ratio (OR) of 1.50 (95 percent confidence interval (CI)
= 1.361.65) of obesity among offspring of mothers who smoked during pregnancy
compared with those who did not.
Because pediatric care providers are often the only physicians that a mother sees
between pregnancies, these health care professionals have the potential to initiate
and support maternal smoking cessation. If successful, such interventions have the
potential to reduce not only the harms associated with fetal growth restriction
but also the risk of obesity in the next generation. In the evidence review for
these Guidelines, there were 2 randomized controlled trials (RCTs) of smoking cessation
restricted to the postpartum period, and smoking cessation studies during pregnancy
included 3 relevant systematic reviews, 2 meta-analyses, and 11 RCTs. A 2004 comprehensive
review by The Cochrane Collaboration included all identifiable smoking cessation
trials during pregnancy dating back to 1976. Pooled across 48 trials and including
6 of the 11 RCTs identified by this review, the authors reported that the included
interventions resulted in a relative reduction of 6 percent (RR = 0.94, 95 percent
CI = 0.930.95) in maternal smoking between the intervention and control groups.
The subset of 16 trials that provided information on perinatal outcomes showed a
mean increase in birth weight of 33 g (95 percent = 1155 g), along with a
reduction in both low-birth-weight babies (pooled relative risk (RR) = 0.81, 95
percent CI = 0.700.94) and preterm births (pooled RR = 0.84, 95 percent CI
Most trials combined pregnancy-specific education, advice, and reinforcement. The
authors of the review noted that an intervention that combined rewards with social
support used in two trials led to greater smoking reduction than other strategies.
In the five trials that included smoking relapse prevention, the authors did not
find that interventions prevented women from resuming smoking in late pregnancy
(pooled RR = 0.81; 95 percent CI = 0.631.04).
Among the five RCTs published after the most recent systematic review, a majority
took place in public clinic settings, with one trial extending the intervention
to include the pediatric clinic.,,,
Results were similar to those in the systematic review, with three of four interventions
resulting in a decrease in maternal smoking during pregnancy. No study was associated
with sustained cessation in the postpartum period, which also was consistent with
the systematic review. One trial set in prenatal clinics addressed smoking cessation
in pregnant adolescents using an intervention based on cognitive behavior theory.
Subjects were randomized to usual care, the "Fresh Start" or "Fresh Start Plus"
intervention programs, with a female friend. Smoking status was assessed by self-report
and cotinine levels. At 8 weeks postrandomization, those in the Fresh Start Plus
group were significantly more likely to be abstinent than those in the usual care
group (OR = 2.106 (0.542, 8.190)); there was no difference between the program alone
and either comparison group. However, at 1-year postrandomization, there was no
difference in abstinence rates between any of the groups.
Two studies addressed smoking cessation in the postnatal period, with subjects identified
via the newborn nursery. The first study in breastfeeding mothers addressed reducing
the infant's exposure to passive smoke. Intervention subjects received specific
guidance about limiting the infant's exposure to cigarette smoke and a room air
cleaner to be placed in the infant's bedroom. Tobacco exposure was assessed
by nicotine and cotinine levels in breast milk and in infant urine samples. In both
the intervention and usual care groups, women smoked twice as much at 2 and 5 weeks
postdelivery as they did during pregnancy. Infant urinary nicotine and cotinine
levels increased over time in both groups, with no significant difference between
the groups at 2, 3, or 5 weeks. A much larger study enrolled 2,901 mothers at the
first infant postnatal visit to the pediatric clinic. Half of the mothers
received the usual advice about limiting smoke exposure at that visit. The other
half received specific antismoking guidance at each nonurgent visit in the first
6 months of life, an average of 4 exposures. When babies were age 6 months, there
were significantly fewer smokers in the intervention group among both those who
had stopped smoking for the pregnancy and those who had continued to smoke. However,
this difference was not sustained at 1-year followup.
CONCLUSIONS AND GRADING OF THE EVIDENCE REVIEW ON MATERNAL SMOKING CESSATION
- The Expert Panel finds that strong evidence supports a benefit for interventions
directed at maternal smoking cessation during pregnancy (Grade A). Weaker evidence
suggests that these interventions do not prevent relapse postpartum. Trials of cessation
in the postpartum period, which would be the most applicable to pediatric providers,
are limited in number and suggest that for maternal smoking cessation to be sustained,
specific continued support in the pediatric care setting is required.
- No smoking cessation interventions reported any adverse effects related to the interventions
- The Expert Panel believes that pediatric care providers can play a role in helping
mothers remain smoke free or quit smoking in the interpregnancy interval.
For most women, this interval extended to the early first trimester of any subsequent
pregnancy. The pediatric well-child schedule calls for about 10 visits in the first
2 years of life; since mothers attend most visits, the pediatric care provider usually
sees women in this period more than any other health care professional. Pediatric
care providers often have a sustained relationship with mother and baby, and many
already advocate for parental smoking cessation in their efforts to promote a smoke-free
environment for children. Pediatric providers and/or their staffs need to be trained
to either deliver or refer to a long-term maternal smoking cessation program (no
Table 131. Evidence-Based Recommendations for Maternal Smoking Cessation
Grades reflect the findings of the evidence review.
Recommendation levels reflect the consensus opinion of the Expert
Supportive actions represent expert consensus suggestions from
the Expert Panel provided to support implementation of the recommendations.
Smoking cessation guidance during pregnancy is strongly advised
- Pediatric care providers should be provided with appropriate training and materials
to deliver, or refer to, a smoking cessation program in the postpartum period for
all smoking women of childbearing age.
- This intervention should be linked to ongoing smoke-free home recommendations directed
at all young mothers and fathers, as described in Section VII. Tobacco Exposure.
Gillman MW. Developmental origins of health and disease. N Engl J Med 2005;353(17):1848-1850.
Boney CM, Verma A, Tucker R, Vohr BR. Metabolic syndrome in childhood: Association
with birth weight, maternal obesity, and gestational diabetes mellitus. Pediatrics
Whitaker RC. Predicting preschooler obesity at birth: the role of maternal obesity
in early pregnancy. Pediatrics 2004;114(1):e29-e36.
Barker DJ, Osmond C, Forsen TJ, Kajantie E, Eriksson JG. Trajectories of growth
among children who have coronary events as adults. N Engl J Med 2005; 353:(17):
Rich-Edwards JW, Kleinman K, Michels KB, Stampfer MJ, Manson JE, Rexrode KM, Hibert
EN, Willett WC. Longitudinal study of birth weight and adult body mass index in
predicting risk of coronary heart disease and stroke in women. BMJ 2005;330(7500):1115.
Oken E, Levitan EB, Gillman MW. Maternal smoking during pregnancy and child overweight:
systematic review and meta-analysis. Int J Obes (Lond) 2008;32(2):201-210. (PM:18278059)
Lumley J, Oliver SS, Chamberlain C, Oakley L. Interventions for promoting smoking
cessation during pregnancy. Cochrane Database Syst Rev 2004(4):CD001055. (PM:15495004)
Hotham ED, Gilbert AL, Atkinson ER. A randomised-controlled pilot study using nicotine
patches with pregnant women. Addict Behav 2006;31(4):641-648. (PM:15985339)
Polanska K, Hanke W, Sobala W, Lowe JB. Efficacy and effectiveness of the smoking
cessation program for pregnant women. Int J Occup Med Environ Health 2004;17(3):369-377.
Pbert L, Ockene JK, Zapka J, Ma Y, Goins KV, Oncken C, Stoddard AM. A community
health center smoking-cessation intervention for pregnant and postpartum women.
Am J Prev Med 2004;26(5):377-385. (PM:15165653)
Stanton WR, Lowe JB, Moffatt J, Del Mar CB. Randomised control trial of a smoking
cessation intervention directed at men whose partners are pregnant. Prev Med 2004;38(1):6-9.
Albrecht SA, Caruthers D, Patrick T, Reynolds M, Salamie D, Higgins LW, Braxter
B, Kim Y, Mlynarchek S. A randomized controlled trial of a smoking cessation intervention
for pregnant adolescents. Nurs Res 2006;55(6):402-410. (PM:17133147)
Stepans MB, Wilhelm SL, Dolence K. Smoking hygiene: reducing infant exposure to
tobacco. Biol Res Nurs 2006;8(2):104-114. (PM:17003250)
Wall MA, Severson HH, Andrews JA, Lichtenstein E, Zoref L. Pediatric office-based
smoking intervention: impact on maternal smoking and relapse. Pediatrics 1995;96(4
Pt 1):622-628. (PM:7567321)
Severson HH, Andrews JA, Lichtenstein E, Wall M, Akers L. Reducing maternal smoking
and relapse: long-term evaluation of a pediatric intervention. Prev Med 1997;26(1):120-130.
Back to Top
Back to Table of Contents