Managing Obesity Before Pregnancy – CMACE/RCOG Joint Guideline

You are advised to get into shape before you conceive.

Dr  Mathew Capehorn, Clinical Director, National Obesity Forum and Clinical Manager at the Rotherham Institute for Obesity, reviewed how and why it is important to advise women about weight management before they become pregnant (19th March 2010).

His presentation focused on overcoming challenges to implementing two key guidelines points:

• Primary care services should ensure that all women of childbearing age have the opportunity to optimise their weight before pregnancy. Advice on weight and lifestyle should be   given during family planning consultations, and weight, body mass index and waist circumference should be regularly monitored.
• Women of childbearing age with a BMI _30 should receive information and advice about the risks of obesity during pregnancy and childbirth, and be supported to lose weight before conception.

The challenges of calculating BMI in children who become pregnant under the age of 18 was highlighted. If the adult standard formula for calculating BMI {Wt (kg) x height (cm)2} is used it will seriously underestimate the BMI of the young person. It is therefore important to use BMI centile charts for girls. The problem of teenage pregnancy in the UK is well documented 1,2.

There are numerous important reasons why health care for obese pregnant women is important. Pregnancy outcomes among obese is poorer compared to non-obese in many respects:

Maternal and Fetal Risks in obese women with BMI Equal or Greater 30.

Source CMACE/RCOG Joint Guideline Appendix 3.

Furthermore, babies born to obese mothers are known to develop a number of chronic childhood diseases including diabetes and obesity.
On the other hand there is good supporting evidence that weight reduction leads to improved pregnancy outcomes including the reduction of diabetes in pregnancy 3, 4.

Supplementation is important:

• Women with a BMI greater than 30 wishing to become pregnant should be advised to take 5mg folic acid supplementation daily, starting at least one month before conception and continuing during the first trimester of pregnancy.

• Health professionals should take particular care to check that women with a booking BMI greater than 30 are following advice to take 10micrograms Vitamin D supplementation daily during pregnancy and while breastfeeding.

Taking pre-conception folic acid is associated with a decrease in the incidence of neurotube defects by up to 72%. 5mg of Folic acid daily is recommended for a couple of months before conception, because obese have been found to have lower folate levels and are at a higher risk of fetal abnormalities. See table above.
My personal view is that women should be advised to take good quality supplements of Vitamin D and B complex for several reasons.

• There is evidence to support the view obese women do not eat healthily, contributing their state of obesity.
• That there is wide spread deficiency of Vitamin D in the population.
• Vitamin B series, particulary folic acid and Vitamin B6, are vital for the metabolism of homocystine, whose metabolic disorders is known to lead to CVD 5,6, 7.
• Even in the absence of genetic predisposition of homocystine metabolic disorders, low folate, Vitamin B12 and B6 could be contributory factors in the pathogenesis of cardiovascular disease, prevalent in obese individuals.

Advising losing weight in pregnancy is challenging because complex nutritional needs of the pregnant woman. It is best to advise on a balanced diet and exercise. Personally, I advise pregnant women to eat healthily in order to maintain weight rather to lose weight. It is unlikely that that a woman who has not been overweight before pregnancy will gain excessive weight to endanger her life or her pregnancy.

Dr Capehorn provided some tips on weight loss in general, and one of the chart is reproduced here.
Energy expenditure for various activities:

The advice to women aspiring to lose weight before, during or after pregnancy is that consistency of activity is far more important that an irregular, one off activity as a means of burning calories.

References for this paper:
1.    Zosia Kmietowicz
US and UK are top in teenage pregnancy rates
BMJ. 2002; 324(7350): 1354.
2.    Debbie A Lawlor J
Teenage pregnancy rates: high compared with where and when?
R Soc Med 2004;97:121–123
3.    Artal R, Lockwood CJ, Brown HL
Obstet Gynecol. 2010;115(1):152-5.
Weight gain recommendations in pregnancy and the obesity epidemic.

4.    http://www.iom.edu/Reports/2009/Weight-Gain-During-Pregnancy-Reexamining-the-Guidelines.aspx

5.    Strain JJ, Dowey L, Ward M, Pentieva K, McNulty H
Proc Nutr Soc. 2004;63(4):597-603.
B-vitamins, homocysteine metabolism and CVD.

6.    McKinley MC
Proc Nutr Soc. 2000;59(2):221-37.
Nutritional aspects and possible pathological mechanisms of hyperhomocysteinaemia: an independent risk factor for vascular disease.

7.    Daly S, Cotter A, Molloy AE, Scott J
Semin Vasc Med. 2005 May;5(2):190-200.
Homocysteine and folic acid: implications for pregnancy.