Intended for healthcare professionals

Rapid response to:

Feature Teenage Pregnancy

Has Britain solved its teenage pregnancy problem?

BMJ 2014; 348 doi: (Published 14 April 2014) Cite this as: BMJ 2014;348:g2561

Rapid Response:

Re: Has Britain solved its teenage pregnancy problem?

Is Obesity Related Metabolic Syndrome the Real Cause of Fewer Teen Pregnancies?

This rapid response is resubmitted as there have been very recent, relevant updates of data for teen pregnancies in the United States of America (USA) and for obesity rates by age and ethnicity in New Zealand (NZ).

It appears heartening that unplanned conception and pregnancy rates in teenagers are decreasing in England1, NZ2 and the USA3. However, we should be careful about being sure that our social programmes and availability of new family planning technologies are the only mechanisms that are solving this problem.

The authors of the recent BML article on England’s teen pregnancy rates state reasons are mostly likely due to a comprehensive social and health service strategy, initiated in 2000 which ‘ … included advertising campaigns, providing better information and access to contraceptives, encouraging good sex education, and more discussion of sexual health with general practitioners’ and ‘...local authorities appointed local teenage pregnancy coordinators as the contact point for all those involved from local health services, education, social services, youth services, housing, and the voluntary sector’1.

Research reports from New Zealand2 4 cited similar information on modern types of, and more available, contraceptive methods. However, unfortunately both countries have had much social support service and structure cut back in the last 4-6 years1 2 and the teen pregnancy rates are still decreasing. In the USA, from 1995-2004, reported abstinence form starting sexual activity, which has become the dominant sexual health message for teens, is also thought to have contributed5. However, during this period of decline in teen pregnancy or live births sexually transmitted infection (STI) levels continued to rise, although NZ & USA countries seemed have changed their reporting in 2011 and report declining rates of STI of approximately of 5% between 2011 and 20126 7.

The effect of the obesity epidemic on conception is not being considered. Teenagers’ average body mass index (BMI) has increased markedly over the last 20 years and in 2012 obesity rates were just under 20% in the USA. In NZ overall childhood rates of obesity are 11%. However, NZ Maori and Pasifika children had obesity rates of 19% & 27% in 2012/13, and teen obesity rates may be closer to Maori and Pasifika adult rates of over 48% and 68%, respectively, some of the highest rates in the world8 9.

There may be an effect on sexual relationships are which are possibly inhibited in obese teenagers, particularly girls5 10.

On a more biological note, however, obesity has long been associated with decreased rates of conception11 and poor pregnancy outcome12. Why has this not been considered as a reason for declining teen pregnancy rates3? Central obesity is associated with ectopic fat accumulation and metabolic syndrome. Part of the metabolic syndrome complex is hypertension, a well-known problem for pregnant women and their babies, and discussed in this issue of the BMJ13. In addition, central obesity is frequently associated with polycystic ovary syndrome (PCOS) in women12. Ovarian insulin resistance, excess androgen production in theca cells, suppression of oestrogen, follicular development and inhibited ova release associated with ovarian cysts results in irregular menstrual cycles, anovulation, and infertility. Androgenised skin acne, excess body hair and risk of type II diabetes, hypertension and cardiovascular disease is also common in PCOS.

When it comes to weight loss to improve conception decreasing obesity by caloric reduction is frequently promulgated. However, metabolic syndrome reduction is even more important, and needs to start pre-pregnancy. Obesity is known to be a malnutritive state. Low grade nutrient insufficiency, lack of food antioxidants for important antioxidant pathways14 15 and increased inflammatory activation16 may be the main reason for failing to achieve conception, and healthy pregnancies for mothers and babies17 18. There is enough worrying data on future health of offspring of obese, poorly fed mothers especially if concurrent tobacco and alcohol consumption is high. This next generation will be at risk for higher rates of fat to lean tissue19, obesity and CVD risk, let alone likely mental health and behavioural issues (eg impulse control) and reduced cognitive potential.

Notably, the greatest rate of decline in pregnancies in the teen age years is in the poorer, least well fed groups20 21. Unfortunately, often there are increased rates poverty in ethnic minorities3 who are overrepresented by displaced colonised indigenous or immigrant/’imported’ manual worker groups.
As noted, Maori have very high rates of obesity and related poor health, and poverty. However, in the pre-colonial and recent past they have had a well-accepted, well-functioning open adoption system (whangai) . Children who cannot be cared for by their biological parents often live with other members of the wider family who do not have children. This system may have accounted for lower contraceptive use rates and abortion amongst this group. However, this open adoption system and Maori society may already be under threat, as the number of children available is too few to support this system.

The general and reproductive health of many ethnic groups has depended on previously fertile teenagers world-wide. Now teenagers of these groups may be amongst the most at risk of suffering from inadequate dietary nutrients, increased persistent toxin load and obesity related metabolic syndrome. The fewer offspring also have increased future health risk.

Thus, some of societies’ social services are gratified that there are less accidental pregnancies, and individual teenagers may be pleased to not conceive. However, some of these teens’ families and their ethnic groups may be very concerned about ominous underlying causes of the decrease in births in our teenagers; they are no longer the fittest providers of many cultures’ next generation.

A Spanish gynaecologist has been recorded as saying on behalf of assisted reproduction that ‘The control of excess weight should be mandatory not only for improving reproductive and obstetric outcomes but also for reducing costs derived from the greater consumption of drugs in IVF, failed treatments, maternal and neonatal complications, and metabolic and non-metabolic diseases in the offspring’11. Rather, the control of obesogenic environments and nutritious food supply needs to be wrested from industry, and handed back to fair-minded governments who are guardians of the futures and health of all ethnic groups in their countries.

1. Arie S. Has Britain solved its teenage pregnancy problem? BMJ 2014;348.
2. Johnson A. Striking a Better Balance: A state of the nation report from the Salvation Army. In: The Salvation Army Social Policy and Parlimentary Unit, editor. Working for the Eradication of Poverty in New Zealand Wellington: Salvation Army, 2014:February.
3. Kost K, Henshaw S. US Teenage pregnancies, births and abortions, 2010: national and state trends by age, race and ethnicity. Guttmacher Institute 2014;
4. Stuart D. Teenage parents in New Zealand: researching rates and responses. In: New Zealand Families Commission-Komihana a Whanau, editor. Families Commission Seminar series,. Wellington: Families Commission,, 2012.
5. Frisco ML, Weden M. Early Adult Obesity and U.S. Women's Lifetime Childbearing Experiences. Journal of Marriage and Family 2013;75(4):920-32.
6. The Institute of Environmental Science and Research Authors. Sexually Transmitted Infections in New Zealand,. In: The Institute of Environmental Science and Research Ltd, editor. Annual Surveillance Report 2012, . Porirua, New Zealand, 2012.
7. Center for Disease Control Authors. 2011 Sexually Transmitted Diseases Surveillance - STDs in Adolescents and Young Adults - In: Centers for Disease Control and Prevention, editor. National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention, Division of STD Prevention. Atlanta, 2012:
8. Ministry of Health. Obesity: Key Facts and Figures New Zealand Health Survey: Annual update of key findings 2012/13. Wellington: Ministry of Health., 2014.
9. Utter J, Faeamani G, Malakellis M, Vanualailai N, Kremer P, Scragg R, et al. Lifestyle and Obesity in South Pacific Youth: Baseline Results from the Pacific Obesity Prevention In Communities (OPIC) Project in New Zealand, Fiji, Tonga and Australia. In: University of Auckland, editor, 2008.
10. Kane JB, Frisco ML. Obesity, school obesity prevalence, and adolescent childbearing among U.S. young women. Soc. Sci. Med. 2013;88:108 -15
11. Kmietowicz Z. Obesity harms a woman’s chances of conception, study shows. BMJ 2013;347(f4418).
12. Wilkes S, Murdoch A. Obesity and female fertility: a primary care perspective. J. Fam. Plann. Reprod. Health Care 2009;35(3):181-85.
13. Clausen TD, Bergholt T. Chronic hypertension during pregnancy. BMJ 2014;348.
14. Mann GE, Niehueser-Saran J, Watson A, Gao L, Ishii T, de Winter P, et al. Nrf2/ARE regulated antioxidant gene expression in endothelial and smooth muscle cells in oxidative stress: implications for atherosclerosis and preeclampsia. Sheng li xue bao : [Acta physiologica Sinica]. Abstract only. 2007;59(2):117-27.
15. Dinkova-Kostova AT, Talalay P. Direct and indirect antioxidant properties of inducers of cytoprotective proteins. Mol. Nutr. Food Res. 2008;52 Suppl 1:S128-38.
16. Ly NP, Litonjua A, Gold DR, Celedon JC. Gut microbiota, probiotics, and vitamin D: interrelated exposures influencing allergy, asthma, and obesity? J. Allergy Clin. Immunol. 2011;127(5):1087-94; quiz 95-6.
17. Wells JCK. Obesity as malnutrition: the dimensions beyond energy balance. Eur. J. Clin. Nutr. 2013;67(5):507-12.
18. Wells JCK. Maternal capital and the metabolic ghetto: An evolutionary perspective on the transgenerational basis of health inequalities. Am. J. Hum. Biol. 2010;22(1):1-17.
19. Wells JC, Chomtho S, Fewtrell MS. Programming of body composition by early growth and nutrition. Proc. Nutr. Soc. 2007;66(3):423-34.
20. Sanz Y. Gut microbiota and probiotics in maternal and infant health. The American Journal of Clinical Nutrition 2011;94(6 Suppl):2000S-05S.
21. King JC. Maternal Obesity, Metabolism, and Pregnancy Outcomes. Annu. Rev. Nutr. 2006;26(1):271-91.

Competing interests: No competing interests

15 May 2014
Anne-Thea McGill
GP and Research Clinician
School of Population Health, University of Auckland
Tamaki Campus, Cnr Morrin and Mertons Rds, Glen Innes, Auckland, New Zealand