Women’s compliance with nutrition and lifestyle recommendations before pregnancy: general population cohort studyBMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b481 (Published 12 February 2009) Cite this as: BMJ 2009;338:b481
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Inskip st al (!) showed in their study that few women change their health behaviour before pregnancy, including the use of folic acid. In this respect we will present a study from the Netherlands evaluating the use of folic acid before conception related to the ‘time to pregnancy’ expected (TTP-expected)
Periconceptional folic acid use decreases the risk of neural tube defects and other birth defects. Since folic acid fortified foods are not mandatory in the Netherlands, women trying to conceive are recommended to use supplements starting at before conception since 1994. Preconceptional care is not structural in the Netherlands which makes, it difficult to reach the women in time. However, the rate of planned pregnancies is high, about 85-90%. Therefore use of supplements can easily be planned as well, provided that women are in time aware of the necessity to start folic acid use before conception.
Data about self-reported FA-use was obtained from a study evaluating in a controlled intervention-reference design the effects of an educational intervention in the community pharmacy (2) on the knowledge about FA and the use of FA-supplements. Our findings show a completely different picture from that reported by Inskip et al. (1). Data were collected at T0 of our design through 23 community pharmacies all of whom had not implemented FA-education interventions before. Random samples of women aged 25-35 that had used oral contraceptives at least one time in the 12 months before T0 were drawn. A sample of 140 women (or smaller if the study population in a pharmacy was less than 280) per pharmacy was drawn. A validated questionnaire was used to collect data with respect to the variables FA-knowledge and consumption (3). Questions about TTP-expected were added. At T0 2821 questionnaires were sent of which 1965 (70%) were returned and 1838 (65%) were eligible for analysis. The table shows the distribution of self-reported FA-supplement use and intention to use FA related to respondents‘ time to pregnancy expected. The data show higher percentages of use and intention to use when the TTP-expected is shorter.
Table . Use or intention to use of folic acid supplements in young women related to ‘time to pregnancy expected’ (TTP-expected).
We would like to add the following comments on these findings. Firstly, in this group the reported FA-supplement use among pregnant women is relatively high compared with the overall pattern in the Netherlands and can be explained by the characteristics of the study population (age, former OC-use). A recent study have however confirmed that OC-use is the strongest predictor of FA-supplement use now. (3) Secondly, although the overall FA-consumption pattern in the Netherlands is lower than in our studygroup, FA-supplement consumption in the Netherlands is much higher than in other countries and has contributed to a decline of NTD birth prevalence (4). This is probably partly due to longstanding and sustained educational interventions in the Netherlands as compared to other countries. Thirdly, our data (not shown here) also reveal strong relations between correct knowledge about FA and TTP-expected. This is in line with the understanding that people are more open to information that applies to their actual situation or expectations and thus emphasizes the need to try and inform women in the right time-window. Finally, preliminary analysis of the data collected at T1 show the same pattern as the data reported here.
In conclusion, our data collected in the preconception time window show that relevant levels of adequate periconceptional FA-consumption are achievable and this contradicts the conclusions of Inskip et al. Interventions implemented in structural health care setting like the community pharmacy contribute to the use of FA before pregnancy.
1. Hazel M Inskip, , Sarah R Crozier, Keith M Godfrey, Sharon E Borland, Cyrus Cooper. Southampton Women’s Survey Study Group. Women’s compliance with nutrition and lifestyle recommendations before pregnancy: general population cohort study. BMJ 2009;338;b481 doi:10.1136/bmj.b481
2. Meijer WM, De Smit DJ, Jurgens RA, De Jong-van den Berg LTW (2004) Pharmacists’ role in improving awareness about folic acid: a pilot study on the process of introducing an intervention in pharmacy practice. Int J Pharm Pract 12: 29-35.
3. de Walle HE,.de Jong-van den Berg LT. Ten years after the Dutch public health campaign on folic acid: the continuing challenge. Eur J Clin Pharmacol. 2008;64:539-43.
4. Busby A, Abramsky L, Dolk H, Armstrong B, Eurocat Folic Acid Working Group. Preventing neural tube defects in Europe: population based study. BMJ 2005;330:574-5.
Competing interests: No competing interests
I refer with interest to your recent BMJ paper "Women's
compliance with nutrition and lifestyle recommendations before pregnancy:
general population cohort study" by Inskip et al in the Research section
and also to a previous paper in the Views & Reviews section on the
importance of accurate data on maternal smoking in pregnancy 1. Our recent
study on risk factors associated with being born small for gestational age
(SGA) in a two year cohort of births from mid-1999 to mid-2001 in a large
Dublin maternity hospital has identified alarming rates of maternal
smoking during pregnancy. SGA was defined as birthweight â‰¤ -2SDS. Of all
the modifiable factors identified as risks for SGA, the strongest case can
be made for endeavouring to decrease smoking amongst pregnant women,
ideally by targeting smoking women before they become pregnant 2
The association of smoking with a reduction in birthweight has been well
established 3. A number of studies have demonstrated an association
between maternal smoking and lower birth weights with estimates of the
reduction ranging from 100 to 300g 4 5 6 7. The effect of maternal smoking
on low birthweight seems to be attributable to intrauterine growth
restriction (OR 2.07) rather than to preterm delivery 4. Looking at the
causal impact of late-term (8th month of gestation) maternal smoking on
birthweight, on average smokers have been found to give birth to infants
weighing 348g less than those of non-smokers 8. A dose-response
relationship has been demonstrated with the degree of impaired fetal
growth and with the average weight deficit of 458g in infants born to
heavy smokers. In addition, passive smoke exposure during pregnancy plays
a role and can result in an average weight deficit of 192g 4 9. However,
some authors have argued that the effects of smoking are confounded by
lifestyle and physiological factors associated with both maternal smoking
and birthweight 10 11. The effect of exposure to cigarette smoking during
pregnancy has also been shown to be modified adversely by advancing
maternal age in an American study by Fox et al., although number of
cigarettes per day and years of smoking were not examined 12.
It is hypothesised that the aetiology of the observed impairment in fetal
growth is due to a combination of carbon monoxide exposure (decreased
fetal haemoglobin oxygen-carrying capacity) and nicotine (inducing
release of maternal catecholamines). This results in repetitive episodes
of reduced maternal perfusion of the placenta. Using a definition for SGA
of birth weight less than the gender specific 10th percentile for
gestational age at birth (in term infants >37 weeks), in the Auckland
Birthweight Collaborative Study the population attributable fraction for
smoking suggested that up to 18% of SGA infants born could be related to
maternal smoking 13.Overall there was a 25.8% rate of maternal smoking in
pregnancy in our study cohort. This compares with rates of smoking found
in similar studies (26.2%) 4 (30%) 14, however a lower rate (11%) has
recently been reported in the USA 15. Overall rates of smoking for women
(irrespective of pregnancy status) in the 18-34 year age group reported by
the Irish Central Statistics Office were 40% and 33% for 1998 and 2002
respectively 16. There was a significant difference found in our study in
the percentage of mothers of SGA infants who smoked during pregnancy
compared with mothers in the non-SGA group. Overall 55% of mothers of
infants born SGA smoked in pregnancy versus 25.7% of the mothers in the
non-SGA group (number of cigarettes ranged from occasional to > 20
cigarettes per day). Similarly, a recent Irish study of the association
between maternal characteristics and birth weight in 1048 live infants has
shown a clear birthweight gradient in relation to maternal smoking, from
38% of mothers of infants in the lowest quintile for birth weight having
smoked, versus 11.4% of mothers of infants in the highest 17. These
findings while concerning are not surprising as cigarette smoking during
pregnancy is the single most common cause of impaired fetal growth 14 and
is also one of the most important avoidable factors associated with low
birth weight 4. In comparison with a specific study of rates of maternal
smoking in groups of SGA infants compared with appropriate for gestational
age (AGA) infants (25% versus 17%) 18 the rate of maternal smoking in the
SGA group in our study appears very high. However, in Doctor et al's
study, SGA was defined as birth weight <10th centile where as we
defined SGA birthweight â‰¤ -2SDS using appropriate references . The
number of cigarettes smoked also appears to be important. For example,
McDonald et al found that smoking more than 20 cigarettes per day was
associated with a more than threefold increased risk of delivering an
infant with a birth weight <_5th centile="centile" _19.="_19." similar="similar" results="results" have="have" been="been" found="found" in="in" our="our" study="study" with="with" _4="_4" of="of" mothers="mothers" sga="sga" infants="infants" smoking="smoking" more="more" than="than" _20="_20" cigarettes="cigarettes" per="per" day="day" versus="versus" _0.7="_0.7" the="the" non-sga="non-sga" group.="group." economic="economic" costs="costs" relation="relation" to="to" low="low" birth="birth" weights="weights" are="are" substantial="substantial" and="and" as="as" it="it" is="is" one="one" most="most" preventable="preventable" factors="factors" associated="associated" births="births" raises="raises" clear="clear" public="public" health="health" issues="issues" this="this" country.="country." intensive="intensive" anti-smoking="anti-smoking" assistance="assistance" pregnant="pregnant" women="women" studies="studies" shown="shown" that="that" some="some" fetal="fetal" growth="growth" retardation="retardation" can="can" be="be" overcome="overcome" _20.="_20." even="even" who="who" stop="stop" first="first" trimester="trimester" pregnancy="pregnancy" may="may" a="a" risk="risk" iugr="iugr" non-="non-" smokers="smokers" _4.="_4." however="however" other="other" interact="interact" during="during" has="has" only="only" half="half" impact="impact" on="on" obese="obese" thin="thin" black="black" white="white" _5="_5" clearly="clearly" just="just" contributory="contributory" for="for" which="which" interacts="interacts" social="social" deprivation="deprivation" maternal="maternal" education="education" diet="diet" pregnancy.="pregnancy." addition="addition" implementation="implementation" best="best" practice="practice" promote="promote" prenatal="prenatal" cessation="cessation" limited="limited" due="due" resource="resource" organisational="organisational" _21.="_21." p="p"/>Although Ireland has led the way in Europe with the introduction of the
law banning tobacco use in the workplace in March 2004 22, 23 24 smoking
rates of young people in Ireland remain high (16% of 12-17 year olds) 25.
The vast majority of smokers start smoking by age 17, but young women are
more likely to start smoking later than young men, but are also more
likely to continue smoking later in life. A study by the Office of Tobacco
Control has reported that 25% of women who commence smoking do so after
age 17 years 26. Hence advertising campaigns to de-glamourise smoking,
targeted specifically at teenage girls, such as the "NICO" campaign,
developed in 2000 27, are well founded. The effects of maternal smoking
during pregnancy are not sufficiently highlighted to this younger age
group and this is an area that requires further development of specific
campaigns. In addition, as smoking during pregnancy is associated with
many later post-natal problems such as lower rates of childhood
immunisation 28, decreased lung function 29 and sudden infant death
syndrome (SIDS) 30 31, women need to be made aware of its long-term
implications. However the message is not being adequately conveyed. For
example, since the "Back to Sleep" intervention campaign initiated in
the UK in 1991 and a 75% overall drop in the incidence of SIDS 32, the
pooled risk associated with maternal smoking during pregnancy has risen to
almost four-fold 33. In October 2007 a leading research team in the UK
concluded that maternal smoking during pregnancy -- already a recognised
factor in 90% of cases of SIDS -- met the criteria for causality and was
directly responsible for 60% of such deaths 30 34. Put in a different
context, up to 60% of cases of SIDS can be avoided by eliminating smoking
during pregnancy 35. Clearly the message on smoking in pregnancy seems to
have achieved less effect than the message on sleeping position 31.Hence,
as stated by O'Gorman 1 tackling social disadvantage is a huge challenge
which has far-reaching implications in the area of smoking prevention. In
addition, the finding by Inskip et al, that those women who became
pregnant within three months of the study interview were not statistically
less likely to be smoking than those who did not become pregnant, is a
further indication that the message on the harmful effects of smoking
during pregnancy is not getting across to women of reproductive age. As
smoking is a notoriously addictive agent, and a substantial proportion of
pregnancies are unplanned, it behoves us to promote public health
campaigns specifically aimed at both smoking prevention and smoking
cessation in women and young girls well before pregnancy occurs.
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summary of vital statistics--2003. Pediatrics 2005;115(3):619-34.
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al. Self-reported pre-pregnancy maternal body mass index and infant birth-
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correlates and neonatal outcomes of small for gestational age infants born
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Competing interests: No competing interests
Quoting from the paper : "Among the women who became pregnant within
three months, 23% answered no at interview when asked if they intended to
become pregnant within the next 12 months. This proportion is lower than
the true unplanned pregnancy rate, as many of those women we have
classified as planning a pregnancy may not have planned to become pregnant
within the three month time window, and so, according to definitions used
in other studies, their pregnancy would have been unplanned." and "[When]
the women became pregnant they attended Southampton’s Princess Anne
Maternity Hospital for fetal ultrasonography at 11, 19, and 34 weeks’
gestation. We collected data on menstruation and ultrasonography from the
women early in pregnancy"
There is a risk of a misunderstanding here. It appears that from the
pregnancies somewhat more than 23% was unintended. However, the unwanted
(and mostly unintended) pregnancies never came to the attention of the
maternity hospital presumably nor the spontaneous abortions. The true
unplanned pregnancy rate will be nearer 50% of all the pregnancies having
occurred in 3 months in the 12445 women. Perhaps the "unplanned pregnancy
rate" should be called ratio with in the denominator ongoing pregnancies.
Competing interests: No competing interests