Making healthy babies

Preconception planning can address a number of fertility factors, writes Dr Karin Hammarberg.

TO HAVE children is a life ambition for most people.^1-3

For some, medical, social or other reasons beyond their personal control prevent them from achieving this aim.

However, for others, factors that potentially are amenable to change reduce their chances of realising this goal.

There is consistent evidence that increasing maternal and paternal age adversely affects fertility and increases risks of pregnancy complication.^4-8

Furthermore, evidence indicates that most people underestimate the influence of increasing female and male age on the chance of conceiving and having a healthy baby.^9-13

As a result of access to reliable contraception and improved education and employment opportunities for women, the age of childbearing has increased.¹⁴

This in turn has lead to an increased rate of age-related infertility and to more couples seeking assisted reproductive technology (ART) treatment to conceive.¹⁵

Unfortunately, the belief that ART can help older women conceive is erroneous; the chance of having a baby with ART decreases with increasing maternal age, and after the age of 40 the chances are negligible.¹⁶ Increasing paternal age is also linked to lower ART success rate.¹⁷

Population data shows that rates of overweight (BMI ≥ 25) and obesity (BMI ≥ 30) are increasing in high-income countries.^18-20

While most people are aware of the negative effects of obesity on general health, its adverse effects on fertility, obstetric outcomes and health of children are less well understood.^{21, 22}

Likewise, in response to sustained health promotion and public information campaigns, there is broad community awareness of the many adverse health effects of smoking. Yet, the negative effects of male and female smoking on fertility may not be known.

Increased public awareness about factors affecting fertility is needed. This may help people make well-informed decisions about family formation; reduce the personal suffering of infertility and adverse obstetric outcomes; and reduce the healthcare costs of treating infertility, pregnancy and neonatal complications.

Health professionals play an important role in improving knowledge among women and men of the effects of age, overweight and smoking on the chance of having healthy children.

Key messages that healthcare professionals should share with their patients include:

Age

• Women’s fertility drops gradually starting at about age 32 and decreases more rapidly after age 35.⁷
• The quality of sperm decreases with age, and partners of men older than 45 take five times longer to conceive than partners of younger men.⁴
• The risk of miscarriage increases with age.^5,8
• The risks of chromosomal abnormalities and birth defects increase with age. Furthermore, advanced paternal age is associated with a greater risk of the child having an autism spectrum disorder.^5,8
• Postponing parenthood incr­eases the risk of involuntary childlessness and fewer children than desired.⁷
• ART treatment cannot overcome age-related infertility.¹⁶
• The risks of obstetric complications such as gestational diabetes, pre-eclampsia, placental abruption, intrauterine growth restriction, premature birth, stillbirth and caesarean section increase with age.^5,6,23

Overweight

• Obesity can cause hormonal imbalances that lead to ovulatory dysfunction and infertility. Male obesity can reduce fertility by lowering testosterone levels and increasing the risk of erectile dysfunction.^{24, 25}
• The risks of obstetric complications such as miscarriage, gestational diabetes, hypertension, caesarean section and premature birth increase.^26,27
• The increased risks to the fetus include congenital abnormalities, high birth weight, stillbirth and perinatal death.^28,29
• Infants of obese mothers have a greater risk of future childhood and adult obesity and all its associated health problems.²⁸

Smoking

• Smokers are more likely to be infertile.^30-32
• Women who are exposed to passive smoking take longer to conceive.³³
• Partners of heavy smoking men take longer to conceive.³⁰
• Women who smoke reach menopause earlier.³⁴
• Maternal smoking increases the risk of low birth weight and birth defects.³⁵
• Smoking can damage sperm DNA. Heavy smoking by fathers at the time of conception increases the child’s risk of childhood leukaemia and shortens the reproductive life span of daughters.^36,37

Key Points

• Health professionals have an important role in raising awareness about factors affecting fertility and obstetric outcomes such as age, obesity and smoking.
• Equipped with factual information, people who have a choice about timing of childbearing can make informed decisions.
• For those who are planning to have children in the future, health professionals’ messages about the adverse effects of obesity and smoking should include their negative effect on fertility and obstetric outcomes.

ConclusionHealth professionals in their care of women and men of reproductive age are in an ideal position to raise awareness about the importance of preconception planning and the effects of age and lifestyle factors on fertility and pregnancy outcomes. In addition to consultation with health professionals, patients can be directed to these evidence-based websites for further information:

www.andrologyaustralia.org
www.yourfertility.org.au
www.betterhealth.vic.gov.au
www.healthinsite.gov.au

References
1.        Holton S, Fisher J, Rowe H. To have or not to have? Australian women’s childbearing desires, expectations and outcomes. Journal of Population Research. 2011;28(4):353-79.

2.        Langdridge D, Sheeran P, Connolly K. Understanding the reasons for parenthood. Journal of Reproductive and Infant Psychology. 2005;23(2):121-33.

3.        Roberts E, Metcalfe A, Jack M, Tough SC. Factors that influence the childbearing intentions of Canadian men. Human Reproduction. 2011;25(5):1202-8.

4.        Hassan MAM, Killick SR. Effect of male age on fertility: evidence for the decline in male fertility with increasing age. Fertility and Sterility. 2003;79(Suppl 3):1520-7.

5.        Jolly M, Sebire N, Harris J, Robinson S, Regan L. The risks associated with pregnancy in women aged 35 years or older. Human Reproduction. 2000;15:2433-7.

6.        Joseph K, Allen A, Dodds L, Turner L, Scott H, Liston R. The perinatal effects of delayed childbearing. Obstetrics and Gynecology. 2005;105:1410.

7.        Schmidt L, Sobotka T, Bentzen JG, Nyboe Andersen A. Demographic and medical consequences of the postponement of parenthood. Human Reproduction Update. 2011;18(1):29-43.

8.        Wiener-Megnazi Z, Auslender R, Dirnfeld M. Advanced paternal age and reproductive outcome. Asian Journal of Andrology. 2012;14:69-76.

9.        Bretherick KL, Fairbrother N, Avila L, Harbord SH, Robinson WP. Fertility and aging: do reproductive-aged Canadian women know what they need to know? Fertility and Sterility. 2010;93(7):2162-8.

10.      Lampic C, Skoog-Svanberg A, Karlstrom P, Tyden T. Fertility awareness, intentions concerning childbearing, and attitudes towards parenthood among female and male academics. Human Reproduction. 2006;21(2):558-64.

11.      Maheshwari A, Porter M, Shetty A, Bhattacharya S. Women’s awareness and perceptions of delay in childbearing. Fertility and Sterility. 2008;90(4):1036-42.

12.      Tough SC, Benzies K, Newburn-Cool C, et al. What do women know about the risks of delayed childbearing. Canadian Journal of Public Health. 2006;97:330-4.

13.      Daniluk J, Koert E, Cheung A. Childless women’s knowledge of fertility and assisted reproduction: identifying the gaps. Fertility and Sterility. 2012;97(2):420-6.

14.      Mills M, Rindfuss RR, McDonald P, te Velde E, on behalf of the ER, Society Task F. Why do people postpone parenthood? Reasons and social policy incentives. Human Reproduction Update. 2011 June 7, 2011.

15.      de Graaff AA, Land JA, Kessels AGH, Evers JLH. Demographic age shift toward later conception results in an increased age in the subfertile population and an increased demand for medical care. Fertility and Sterility. 2011;95(1):61-7.

16.      Wang Y, Macaldowie A, Hayward I, Chambers G, Sullivan E. Assisted reproductive technology in Australia and New Zealand 2009. Canberra: AIHW; 2011.

17.      de La Rochebrouchard E, de Mouzon J, Thebot F, Thonneau P. Fathers over 40 and increased failure to conceive: the lessons of in vitro fertilization in France. Fertility and Sterility. 2006;85(5):1420-4.

18.      Australian Bureau of Statistics. National Health Survey: Summary of results 2007-2008. Canberra: ABS; 2009.

19.      Joint Health Surveys Unit. Health survey for England 2007 latest trends. London, UK: The NHS Information Centre for Health and Social Care; 2008.

20.      McTigue K, Garrett J, Popkin B. The natural history of the development of obesity in a cohort of young US adults between 1981 and 1998. Annals of Internal Medicine. 2002;136:857-64.

21.      Bunting L, Boivin J. Knowledge about infertility risk factors, fertility myths and illusory benefits of healthy habits in young people. Human Reproduction. 2008;23(8):1858-64.

22.      Thompson M, Nassar N, Robertson M, Shand A. Pregnant women’s knowledge of obesity and ideal weight gain in pregnancy, and health behaviours of pregnant women and their partners. Australian and New Zealand Journal of Obstetrics and Gynaecology. 2011;51:460-3.

23.      Fretts RC. Older women have increased risk of unexplained fetal deaths. British Medical Journal. 2001;322:429.

24.      Gesink Law DC, Maclehose RF, Longnecker MP. Obesity and time to pregnancy. Human Reproduction. 2007;22(2):414-20.

25.      Hammoud A, Carrell D, Gibson M, Peterson C, Meikle A. Updates on the relation of weight excess and reproductive function in men: sleep apnea as anew area of interest. Asian Journal of Andrology. 2012;14:77-81.

26.      Athukorala C, Rumbold A, Willson KJ, Crowther CA. The risk of adverse pregnancy outcomes in women who are overweight or obese. BMC Pregnancy and Childbirth. 2010;10:56.

27.      Barau G, Robillard P-Y, Hulsey TC, et al. Linear association between maternal pre-pregnancy body mass index and risk of caesarean section in term deliveries. BJOG. 2006;113:1173-7.

28.      Koepp U, Andersen L, Dahl-Joergensen K, Stigum H, Nass O, Nystad W. Maternal pre-pregnant body mass index, maternal weight change and offspring birth weight. Acta Obstetrica et Gynecologica Scandinavica. 2012;doi: 10.1111/j.1600-0412.2011.01321.x.

29.      Tennant PWG, Rankin J, Bell R. Maternal body mass index and the risk of fetal and infant death: a cohort study from the North of England. Human Reproduction. 2011;26(6):1501-11.

30.      Hassan MAM, Killick SR. Negative lifestyle is associated with significant reduction in fecundity. Fertility and Sterility. 2004;81(2):384-92.

31.      Homan GF, Davies MJ, Norman RJ. The impact of lifestyle factors on reproductive performance in the general population and those undergoing infertility treatment: a review. Human Reproduction Update. 2007;13(3):209-23.

32.      Augood C, Duckitt K, Templeton AA. Smoking and female infertility: a systematic review and meta-analysis. Human Reproduction. 1998;13(6):1532-9.

33.      Hull MGR, North K, Taylor, Farrow A, Ford C. Delayed conception and active and passive smoking. Fertility and Sterility. 2000;74(4):725-33.

34.      ESHRE Task Force on Ethics and Law. Lifestyle-related factors and access to medically assisted reproduction. Human Reproduction. 2010;25(3):578-83.

35.      Hackshaw A, Rodeck C, Boniface S. Maternal smoking in pregnancy and birth defects: a systematic review based on 173 687 malformed cases and 11.7 million controls. Hum Reprod Update. 2011;17(5):589-604.

36.      Milne E, Greenop KR, Scott RJ, et al. Parental Prenatal Smoking and Risk of Childhood Acute Lymphoblastic Leukemia. American Journal of Epidemiology. 2011 December 5, 2011.

37.      Fakuda M, Fakuda K, Shimizu T, et al. Paternal smoking habits affect the reproductive life span of daughters. Fertility and Sterility. 2011;95(8):2542-4.