ABSTRACT
Background: Women aged 35 and older account for an increasing proportion of births and are at increased risk of pregnancy complications and poor infant outcomes. The objectives of the study were: 1) to determine what women know about delayed childbearing, including pregnancy complications and outcomes associated with low birthweight (LBW, <2500 grams), preterm delivery (<37 weeks) and multiple birth, and 2) to assess the characteristics of women with limited knowledge of risks.
Methods: A computer-assisted telephone interview survey was conducted with 1,044 randomly selected women who delivered their first live-born infant, between July 2002 and September 2003, in two urban centres, Calgary and Edmonton, in Alberta, Canada.
Results: The proportion of women aware of specific childbearing risks associated with advanced maternal age were as follows: conception difficulties (85.3%), multiple birth (24.0%), caesarean section (18.8%), preterm delivery (21.8%), and LBW (11.2%). Knowledge of specific developmental and health-related risks of suboptimal infant outcomes ranged between 18.0% and 46.5%. Logistic regression revealed that limited knowledge of maternal age-related pregnancy risks were associated with unplanned pregnancy (OR, 1.48; 95% CI, 1.03-2.14), smoking (OR, 1.83; 95% CI, 1.29-2.60) and non-use of fertility treatment (OR, 2.15; 95% CI, 1.44-3.19). Characteristics associated with limited knowledge of the risks associated with suboptimal birth outcomes were: age 35-39 years (OR, 2.98; 95% CI, 1.35-6.58), less than post-graduate education (≤high school OR, 2.14; 95% CI, 1.20-3.82), and not currently enrolled as a student (OR, 1.75; 95% CI, 1.02-3.00).
Conclusions: Many women are generally unaware of the potential consequences of delayed childbearing. There are missed opportunities in preconception counselling and education, which should be addressed to allow for more informed decision-making about family planning.
MeSH terms: Pregnancy; reproductive behaviour; health knowledge
It is increasingly common for women in developed countries to delay childbearing until they are 35 years or older as they may seek higher educational attainment, secure finances, an advanced career and relationship stability before pregnancy.1-5 However, in addition to challenges in conceiving a pregnancy,6 pregnant women 35 years and older are at increased risk for medical risks,7-10 chromosomal abnormalities (Down Syndrome),11,12 low birthweight (LBW, <2500 grams),13,14 stillbirth and unexplained foetal death,15 preterm delivery (<37 weeks gestation),13,16 multiple birth (twins or triplets)13,17 and increased risk of operative delivery.18 Death during infancy, poor health, and lifelong physical and/or developmental disabilities are potential outcomes for LBW and/or preterm infants.19"22 Thus, the consequences of delayed childbearing may lead to unexpected associated emotional costs to the family, costs to the community and education system, and increased health care utilization.23'26
In the province of Alberta, Canada, the percentage of primiparous women who are aged 35 and older has increased from 4.4% in 1989 to 10.2% in 2001.27 Consistent with this trend, the proportion of births to women aged 35 and greater in Canada has increased from 8.6% to 14.5% between 1991 and 2000,28 and in the United States, the number of first births per 1,000 women 35 to 39 years of age increased by 36% between 1991 and 2001.29 Furthermore, there has been an increase in the LBW rate among women aged 35 and older in Alberta, from 6.9% to 8.6%, between 1994 and 2001.6,27 Rates of preterm delivery among these women has also increased from 8.3% to 10.7%.27,30 Thus, more women are delaying childbirth and an increased proportion are experiencing suboptimal birth outcomes.
As a result of the increasing proportion of births to women aged 35 years or older and the increase in associated risk,30 the objectives of this study were to assess whether women were aware of the risks associated with delayed childbearing and to determine the characteristics of women with limited knowledge. Preconception counselling is intended to inform women about how to plan a healthy pregnancy and determine any potential risks.31 These preconception consultations may be more effective if health care providers are aware of and address gaps in women's knowledge with regard to the risks associated with delayed childbearing. Findings from this study identify, from the women's perspective, gaps in preconception knowledge which could be addressed through clinical counselling as well as public health strategies or social marketing to allow for more informed decision-making in family planning.
METHODS
Participants and setting
Within three months of delivery, women were randomly selected from all Englishspeaking women who had given birth to their first live-born infant between July 2002 and September 2003 within the Calgary Health Region in Calgary and the Capital Health Region in Edmonton, Alberta, Canada. Provincial data indicated that rates of delayed childbearing were highest in these urban centres, where 17.9% and 21.8% (Edmonton and Calgary, respectively) of births in 2001 were to women aged 35 or older.27 To ensure a sufficient sample size to determine if the mother's age was related to the mother's knowledge of the impact of delayed childbearing, women 35 or older were over-sampled.
Ethics approval was obtained from the University of Alberta and the Conjoint Ethics Board at the University of Calgary and the Calgary Health Region. All women provided written or verbal consent to participate.
Questionnaire
Based on information from focus groups, previous surveys, and expert input, a questionnaire was designed specifically for this study. The questionnaire was pilot tested by trained interviewers with women of childbearing age who were not part of this study. Women were asked to provide feedback on the duration of the questionnaire, clarity and suitability of question content and wording. The face and content validity of the questions related to knowledge of risks was ensured through focus group testing and pilot interviews as well as through consultation with medical experts. The questionnaire contained three sections: background information (including sociodemographic characteristics of the woman and her partner, medical and reproductive history, and family planning), knowledge of maternal age-related risks of childbearing (see items in Table II), and knowledge of the developmental and health-related risks associated with suboptimal infant outcomes (see items in Table IV). Data were collected by trained interviewers using a computer-assisted telephone interview (CATI).
Main outcome measures
Responses to each item in the two knowledge sections were coded as correct or incorrect. The percentage correct was calculated to create an overall score on knowledge tar each section. Traditional scoring methods of pass versus failure have been established at 50%, so overall scores were dichotomized into two groups: those who responded correctly to <50% of the questions (limited knowledge) and those who responded correctly to >50% of the questions (reasonable knowledge).
Statistical analyses
Sample size calculations were based on anticipated differences between women less than 35 years and women 35 years and over with regard to demographic and lifestyle characteristics which may have influenced knowledge, such as education. A sample size of 600 women would allow us to detect as significant a difference between groups in these characteristics as small as 7%. The sample size was increased to 1,000 to allow for multivariate analysis and to allow us to control for demographic characteristics depending on the findings of the bivariate analysis.
Data were analyzed using SPSS/PC version 12.0. Alpha was set at p<0.05. Frequencies of responses to selected questions were determined. Characteristics of women who answered ≤50% of questions correctly were compared to women who answered >50% of questions correctly using Chi-square tests. Unconditional logistic regression, using the forward. method, was used to develop models that described the independent characteristics of women who had limited knowledge about delayed childbearing. Confounding and interaction were evaluated by bivariate logistic regression. Two final models were developed: one for limited knowledge about maternal age-related risks of childbearing, and another for limited knowledge about developmental and health-related risks of suboptimal infant outcomes. Goodness of fit was tested for the models using the Hosmer and Lemeshow test.
RESULTS
Participants
The survey was completed by 1,044 women, with a response rate of 72%. Respondents tended to be Caucasian, mar-, ried, employed, well educated and of higher income (Table I). Prior to conception, 43.4% of women received information concerning pregnancy from their physi-
Knowledge about maternal age-related risks of childbearing
Table II provides details on the responses to the questions about maternal age-related risks of childbearing. Less than 25% of women knew that women aged 35 or older were at increased risk of caesarean section delivery, multiple birth, low birthweight or preterm delivery.
Overall, only 37% (n=369) of respondents scored greater than 50% on items about maternal age-related risks (Table III). When variables found to be significant at the bivariate level were considered for regression (Table III), smoking, not planning a pregnancy and non-use of assisted reproduction significantly predicted limited knowledge about maternal agerelated issues. There were no interaction effects. The fit of this model was acceptable (Hosmer and Lemeshow significance = 0.916).
Women who gave birth to multiples were significantly more likely to answer the maternal age-related questions correctly and to have required assistance with conception. There was no difference in response patterns for women who delivered low birthweight or preterm infants.
Knowledge about developmental and health-related risks associated with suboptimal infant outcomes
Compared to normal birthweight or fullterm delivery, only 36.5% of respondents recognized that low birthweight was a risk factor for learning difficulties and 46.5% recognized that preterm infants were at increased risk for health problems (see Table IV). Fewer than 25% of women identified other potential developmental and health-related risks of low birthweight, preterm delivery, or multiple births.
Overall, only 15.6% (n=162) of respondents scored 50% or higher on questions about risks associated with suboptimal infant outcomes (Table V). Those who scored high were significantly (p<0.05) more likely to be older (40 years and older), to have a post-graduate education, or to be enrolled as a student 6 months prior to pregnancy. When these three variables were considered for a final model using forward selection, all remained significant. The fit of this model was acceptable (Hosnier and Lemeshow significance = 0.871).
There was no difference in response patterns for women who delivered multiples, low birthweight or preterm infants.
DISCUSSION
These findings indicate that among an urban sample of women delivering their first live-born child, a few risks of delayed childbearing (i.e., conception difficulties and Down Syndrome) are recognized while many others are not. Women planning a pregnancy or seeking fertility support were more informed about age-related risks. However, women overall were unaware of important potential consequences of delayed childbearing, such as preterm delivery and the associated developmental and health-related risks for the child. This indicates that the majority of women are making family-planning decisions in the absence of sufficient information.
It may he that the scope of information surrounding pregnancy and risk is either not in a useful format for patients, or that time is a barrier to discussion with clients.32 Although the Society of Obstetricians and Gynaecologists of Canada (SOGC) guidelines encourage physicians to discuss preconception topics such as smoking and alcohol use, given demands on family physicians, it is possible that office visits are restricted to presenting needs.31-33
Current media messages about delayed childbearing are mixed and highly influenced by the North American entertainment industry where celebrities are postponing first-time motherhood into their late 30s and beyond.34 Popular literature, including magazine and newspaper articles, typically focusses on conception and overcoming conception difficulties (fertility treatment) rather than the risks and potential consequences of delayed childbearing for both mother and child. Furthermore, these articles may inadvertently emphasize the positive birth outcomes or 'miracles', with less attention paid to those who experienced preterm delivery, infant mortality or low birthweight outcomes. For instance, Canadian magazines have included "Getpregnant guides"35 and include stories with titles such as "Middle-aged moms"36 and "Kids vs. Career".37 While these stories examine some of the medical risks of pregnancies at later ages, they generally focus on issues related to career development and parenting. Given the broad circulation of these magazines, there are potential opportunities to include more comprehensive articles that would facilitate more informed decision-making by families.
Some study limitations are of note. Although women were asked to respond to the questionnaire with respect to their level of knowledge prior to pregnancy, the potential exists that women could not separate knowledge gained through pregnancy from what was known prior to pregnancy, and responses could have been biased. It this had occurred, we would have overestimated the level of knowledge women had prior to pregnancy, suggesting an even greater need for preconception counselling or knowledge dissemination. Furthermore, delivery of a low birthweight or preterm infant may also have influenced women's responses to questions related to risks associated with infant outcomes. However, we examined the data and found that such birth outcomes had no erfect on knowledge of the developmental and healthrelated risks associated with suboptimal infant outcomes, suggesting that cither respondents answered the questions based on their level of knowledge prior to pregnancy, or that birth outcome did not impact knowledge related to potential sequelae. Finally, these data represent a sample of urban, mainly Caucasian women, and findings may not be generalizablc to all populations.
An increasing proportion ot childbearing women are delaying pregnancy, and this study indicates that many women are uninformed about the potential risks associated with this decision. Thus, there are opportunities to improve public knowledge and awareness of risks associated with delayed childbearing to allow for informed family planning. Public health campaigns may be more effective if they include multilevel approaches, such as cliniciandelivered preconception counselling, public education and/or social marketing strategies.38 These data also provide baseline information against which knowledge gains could be measured in the future.
R�SUM�
Contexte : Une proportion croissante de b�b�s naissent de femmes de 35 ans et plus, lesquelles risquent davantage d'avoir des complications durant la grossesse et d'accoucher de nourrissons d'un poids sous-optimal. Notre �tude visait : 1) � d�terminer ce que les femmes savent au sujet de la procr�ation tardive, notamment des complications de la grossesse et des r�sultats associ�s � l'insuffisance de poids � la naissance (IPN, <2 500 g), � l'accouchement pr�matur� (<37 semaines) et � l'accouchement multiple, et 2) � �valuer les caract�ristiques des femmes qui connaissent mal ces risques.
M�thode : Nous avons men� un sondage t�l�phonique assist� par ordinateur aupr�s de 1 044 femmes, s�lectionn�es au hasard, ayant accouch� d'un premier enfant vivant entre juillet 2002 et septembre 2003 dans deux centres urbains de !'Alberta (Calgary et Edmonton).
R�sultats : Les femmes connaissaient les risques de la procr�ation � un �ge avanc� dans les proportions suivantes : difficult�s � concevoir (85,3 %), accouchement multiple (24 %), accouchement par c�sarienne (18,8 %), accouchement pr�matur� (21,8 %), et IPN (11,2 %). Entre 18 % et 46,5 % des r�pondantes connaissaient les risques d�veloppementaux et sanitaires auxquels est expos� un nouveau-n� de poids sous-optimal. Une analyse de r�gression logistique a montr� que la connaissance limit�e des risques de la grossesse � un �ge maternel avanc� �tait associ�e � la grossesse non planifi�e (RC = 1,48; IC de 95 % = 1,03-2,14), au tabagisme (RC = 1,83; IC de 95 % = 1,29-2,60) et au fait de ne pas avoir subi de traitement de l'infertilit� (RC = 2,15; IC de 95 % = 1,44-3,19). Les caract�ristiques associ�es � la connaissance limit�e des risques de l'IPN �taient les suivantes : avoir entre 35 et 39 ans (RC = 2,98; IC de 95 % = 1,35-6,58), ne pas avoir fait d'�tudes postsecondaires (moins qu'un dipl�me d'�tudes secondaires : RC = 2,14; IC de 95 % = 1,20-3,82), et ne pas �tre inscrite en tant qu'�tudiante (RC = 1,75; IC de 95 % = 1,02-3,00).
Conclusions : Nombre de femmes ont peu conscience des r�percussions possibles de la procr�ation tardive. Il y aurait des lacunes � combler sur le plan du counselling et de l'�ducation avant la grossesse pour favoriser une prise de d�cisions plus �clair�e en mati�re de planning familial.
[Reference]
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Received: February 17, 2005
Accepted: September 19, 2005
[Author Affiliation]
Suzanne Tough, PhD1,2
Karen Benzies, PhD3
Christine Newburn-Cook, PhD4
Karen Tofflemire, MSc1,2
Nonie Fraser-Lee, MHSA5
Alexandra Faber, MSc2
Reg Sauve, MD1,2
[Author Affiliation]
1. Department of Medicine, University of Calgary, Calgary, AB
2. Calgary Health Region, Calgary
3. Department of Nursing, University of Calgary
4. Department of Nursing, University of Alberta, Edmonton, AB
5. Population Health and Research, Capital Health, Edmonton
Correspondence and reprint requests: Suzanne Tough, Alberta Children's Hospital, Room 3013, 1820 Richmond Rd. SW, Calgary, AB T2T 5C7, Tel: 403-943-2272, Fax: 403-943-7214, E-mail: suzanne.tough@calgaryhealthregion.ca
Acknowledgements: Trie authors acknowledge the following individuals for their contributions to this study: Monica Jack, BComm, BSc, Corine Frick, MN, and lan Lange, MD.
Source of funding: Alberta Heritage Foundation for Medical Research
