16 April, 2007

Obesity and pregnancy

The three major specialist journals carry articles on obesity and pregnancy this month. The definitions are; a BMI over 25 is overweight, over 30 obese, over 35 grossly obese, and over 40 morbidly obese.

The BJOG (Heslehurst 2007;114:187-94) traces maternal obesity over the last 15 years which shows the incidence has increased from 10% to 16% and, if the trend continues, by 2010 the rate will be 22%. This carries implications for hospital staff, facilities and special clinics all requiring more resources.

Some of those requirements will be far more caesarean sections. Bergholt et al (AJOG 2007;196:163-5) tracked a group of uncomplicated primipara and worked out their chances of an emergency CS in labour. Taking women with a BMI of less than 25 as controls, CS rates rose with BMI with those who were grossly obese having four times the risk of a CS. Failure to progress and suspected fetal distress were the main indications while one-quarter of the remaining women had an instrumental delivery.

The authors advise telling women with raised BMIs about their increased risk of CS delivery. Clinicians and patients should be aware of these statistics and share them with labour ward staff.

In the US, more than half of women of reproductive age are overweight and 30% are obese. The lower the socio-economic status, the greater the incidence of obesity. There is a spread of related problems which Catalano (Obstets Gynecol 2007;109:419-33) iterates sequentially: greater risk of miscarriage and congenital abnormalities, later manifestations of the metabolic syndrome including diabetes, cardiac dysfunction, proteinuria, sleep apnoea and fatty-liver disease, greater risk of caesarean section with anaesthetic difficulties, operative challenges, wound disruption or infection and clotting risks. Fetal risks in the short-term are macrosomia and obesity with related poorer outcomes plus long-term consequences in adolescence and adulthood of the metabolic syndrome.

03 April, 2007

Is fish safe in pregnancy?

Some long-chain omega-3 fatty acids are essential for optimal neuro-development in the fetus. Fish is a rich source of these nutrients but there have been suggestions that fish could contain toxins like mercury that could be detrimental to brain function. Indeed, the current US governmental recommendations advise not more than three servings of seafood per week for pregnant women, but there may be a danger that such restrictions could be counter-productive and can result in fetal brain malnutrition.

This is quite an issue so the study by Hibbeln et al (Lancet 2007;369:578-85) is a welcome source of information. They investigated 12 000 children whose mothers had recorded how much seafood they ingested during the index pregnancy and measured it against the child's intellectual, social, communication and fine-motor development up to 8 years of age. They found that the lower the seafood intake, the greater the risk of dysfunction. Fish was protective of normal development and function - exactly the opposite of the US advice. On balance, women are not putting their unborn child at risk by eating three or more portions of fish per week.

As Myers & Davidson say in an editorial (Lancet 2007;369:537-8), the dangers of fish-eating in pregnancy have been misrepresented and are misleading and are not based on any evidence of harm.

March JASS is out

“We are what we eat” is an old chestnut.

The journals are full of articles on how diets affect risk of disease and, with the prevalence of obesity at an all-time high, there is no lack of publications on diets that affect weight. The dangers of being overweight in pregnancy are well documented and the review by Catalano (see summary) highlights these.

Those wishing to supplement their diets with healthy additives should do so with caution. More is not necessarily better and the antioxidant story is sobering.

Pregnant women's intake is also revealing and the article on the dangers of eating fish is a real “myth-buster”.

Also in the life-style paradigm, sex is enjoying a greater press with the tensions between medicalising sexual function and suppressing information receiving attention. What is normal function and what is dysfunction?

You decide how much is enough of what!