Dieticians call for action on overweight mothers-to-be

Medical Tribune July 2009 P16

David Brill

Overweight women should receive nutrition counseling before, during and after pregnancy, leading US dietitians have advised.

With the global obesity epidemic showing no signs of slowdown, the health of mothers and babies alike is at risk unless eating habits improve, cautions a recent joint statement from the American Dietetic Association (ADA) and the American Society of Nutrition (ASN).

Studies show that obese mothers are more likely to experience preeclampsia, gestational diabetes mellitus (GDM), gestational hypertension, postpartum anemia and cesarean delivery than women of normal weight. Their offspring, meanwhile, face an increased risk of birth defects, fetal macrosomia, childhood obesity and even perinatal death.

Ms. Ximena Jimenez, a consultant dietitian and national ADA spokesperson, said that healthcare professionals across the spectrum should work together to promote healthy eating and physical activity in women who are pregnant or planning to conceive. Physicians, for example, can play “a big role” in reinforcing the advice given by dietitians and other specialists, she said.

“A lot of the time it takes more than one type of counseling to get these women to change their lifestyle. I would encourage any healthcare professional to encourage these women to seek nutrition counseling,” she said.

“The principles are that you want them to increase whole grains and decrease refined carbohydrates like cakes, pastries and white breads. We also want them to replace saturated fat with healthy fats like omega-3 fats or fats from olive oil, canola oil or avocado, and also to increase their intake of fruits and vegetables. We also want them to be physically active,” she added.

Some 52 percent of women aged 20 to 39 in the US are overweight or obese (BMI 25 or above), according to data from the National Health and Nutrition Examination Survey of 2003-2004. Twenty-nine percent are obese (BMI 30 or above) and 8 percent are extremely obese (BMI 40 or above). Among adolescent girls aged 12 to 19, almost 32 percent are overweight or at risk of being overweight. [JAMA 2006 Apr 5;295(13):1549-55]

Despite the scale of the task, Jimenez remains optimistic that overweight women can be successfully counseled.

“I think it’s a very realistic target. There has to be promotion of healthy eating among women,” she said. “Imagine the benefits. As a society we are all going to benefit because we are going to have healthy women and healthy children.”

Jimenez highlighted studies showing the success of dietary interventions in overweight mothers, such as the Nurses’ Health Study, which found that risk of GDM was approximately halved by following a low-glycemic, high-cereal fiber diet. [Diabetes Care 2006 Oct;29(10):2223-30] The risk of preeclampsia can also be halved by taking calcium supplements, a meta-analysis of 12 studies shows. [Cochrane Database Syst Rev 2006 Jul 19;3:CD001059]

The new ADA / ASN position statement also reviews the literature on the prevalence of various pregnancy outcomes for overweight mothers and their babies. [J Am Diet Assoc 2009 May;109(5):918-27]

The risk of developing GDM, for example, is reported to double in overweight women, and increase over eightfold in the extremely obese. [Diabetes Care 2007 Aug;30(8):2070-6] Preeclampsia risk is around three times higher in pregnant women who are obese than those of normal weight. [Obstet Gynecol 2007 Feb;109:419-33]

The offspring of obese mothers are around twice as likely to have neural tube defects such as spina bifida, according to the US National Birth Defects Prevention Study. [Arch Pediatr Adolesc Med 2007 Aug;161(8):745-50] Oral clefts, hydrocephaly and cardiac abnormalities were also found to be more common in these infants than those born to normal-weight mothers.

Caffeine in pregnancy restricts fetal growth, study warns

Medical Tribune February 2009 P6

David Brill

Consuming caffeine during pregnancy can significantly increase the risk of fetal growth restriction, according to one of the largest and most comprehensive studies to weigh in on a notoriously inconclusive debate.

Pregnant women are typically advised to reduce their caffeine intake as a sensible precaution, but research findings have been inconsistent and a definitive link to birth defects has remained elusive.

The new study, which claims to be the first to give a “true picture” of caffeine intake in pregnancy, found that the association was significant at all levels of consumption and continued throughout pregnancy.

The size of the effect is similar to that seen for alcohol consumption, the UK researchers reported in the British Medical Journal. [2008 337:a2332] They recruited 2,635 low-risk women at 8 to 12 weeks of pregnancy and followed them up until birth.

An intake of more than 200 mg/day of caffeine was linked to an average birth weight reduction of up to 70g (P = 0.004) and increased the odds ratio for having a growth restricted baby to 1.5, as compared to an intake of below 100 mg/day (P = 0.02).

Dr. Shephali Tagore, an associate consultant in the department of maternal fetal medicine at KK Women’s and Children’s Hospital, Singapore, said the study confirms that the advice to reduce caffeine intake before and during pregnancy is appropriate.

“While previous studies have suggested a risk, this study group has objectively quantified caffeine from all known sources. This is a major strength of the study. They have found a dose-response relationship, showing that increasing caffeine intake was associated with increasing risk of fetal growth restriction,” she said.

Tagore added, however, that it is difficult to draw firm conclusions from the paper since there was no control group of women who did not consume any caffeine during pregnancy,

Previous studies have overestimated the impact of tea and coffee and relied too heavily on retrospective recall of caffeine consumption, according to the authors, who took a more thorough approach by using a comprehensive questionnaire which was validated against food diaries and saliva samples.

They found that only 14 percent of the women’s caffeine intake came from coffee. Tea was the major source, comprising 62 percent of intake, with cola drinks and chocolate contributing 12 and 8 percent respectively.

“We believe that, for the first time, this reflects a true picture of total caffeine intake by women during pregnancy,” they wrote. “Our findings emphasize the weakness of studies where caffeine intake was equated to that of coffee alone.”

Caffeine is absorbed rapidly and can cross the placenta freely. The main enzyme for breaking down the compound, however, is not found in the placenta or fetus so exposure depends largely on maternal metabolism.

To investigate whether individual metabolic differences affected fetal growth the researchers also measured the half-life of caffeine in the women’s saliva. The association with fetal growth restriction was strongest in women who had the fastest caffeine clearance but this result did not reach significance (P=0.06).

Caffeine consumption has also been linked to miscarriage. A study published last year found that an intake above 200mg/day more than doubled the risk. [Am J Obstet Gynecol 2008 Mar;198(3):279.e1-8]

Another recent study found that injecting the caffeine equivalent of two cups of coffee into pregnant mice decreased cardiac function and stunted development of the cardiac ventricles in their offspring. [FASEB J 2008 Dec 16 Epub ahead of print]

Simple strategy effective in postpartum depression screening

Medical Tribune February 2009 P16
David Brill

Combining two existing screening tools could be a straightforward, time-saving and effective way to detect postpartum depression (PPD) in primary care, US research has shown.

The first screening stage, comprising two simple yes/no questions, was 100 percent sensitive at detecting PPD, according to the Annals of Family Medicine study. [2009; 7:63-70]

Patients with a positive result on the two-question screen should then progress onto the nine-item Patient Questionnaire (PHQ-9), say the University of Minnesota researchers, who report that this second stage was 92 percent specific. They tested the two-tiered strategy in 506 women who brought their newborn infants for well-child visits at pediatric and family medicine clinics over the course of 9 months.

The screening tools have already been incorporated into routine practice at several Minnesota clinics and are soon to be implemented in three large hospitals, according to Dr. Dwenda Gjerdingen, who led the study.

“We find them easy to administer, patients find them easy to complete, and they give us a good sense of where the patient is at in terms of their mental health,” she said.

“You want your initial screen to be highly sensitive, which this one is: the two-question screen does not miss depressed patients. Then the PHQ-9 is a very specific test so when depressed people complete it and it turns out to be positive, it is likely to be a true positive and not a false positive.”

The two-question screen focuses on the main symptoms of depression: diminished mood and loss of pleasure in activities.

Despite the common nature of PPD – the condition affects around 22 percent of new mothers and is the most common complication of childbirth – less than half of mothers are presently being screened, the authors wrote. The condition not only affects the mother’s wellbeing but can also harm the cognitive development of the infant. [Arch Womens Ment Health 2003 Nov;6(4):263-74]

The results of the new strategy were validated against the Structured Clinical Interview from the Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV. Forty-five (8.9 percent) of the women were found to have major depression.

Gjerdingen noted that the PHQ-9 still missed a few depressed patients, so suspicion should be retained in those who achieve a negative result having scored positively on the initial two-question screen. These women should be advised to see their doctor if they experience a dip in mood, she said.

Both the two-question screen and the PHQ-9 are already used in general depression but had yet to be validated in PPD. Other potential screening options for PPD are available but typically take longer to complete, Gjerdingen said.

Asian women less aware of long-term risks after gestational diabetes

Medical Tribune November 2008 P6
David Brill

Asian-born women who experience gestational diabetes mellitus (GDM) during pregnancy may be less acutely aware of their subsequent risk of developing diabetes, according to an Australian study.

A large postal survey of women with a history of GDM revealed that 92.3 percent knew that the condition predisposes to later development of type 2 diabetes.

Less than 30 percent of the 1,176 respondents, however, considered themselves to be at high or very high risk.

Risk perception was particularly low among Asian-born women, with just 15.5 percent believing themselves to be at high risk – a significantly lower proportion than Australian-born women (P=0.013).

“This is of some concern considering that evidence suggests that this may be in fact the highest-risk group,” said Ms. Melinda Morrison, a pediatric diabetes dietician who presented the study findings.

“We’re talking about Asian women in Australia so it may be down to how the messages are getting through, as well as possible cultural differences,” she said.

She added, however, that the data have yet to be fully analyzed so it is difficult to speculate on possible explanations for the finding at this point.

American Diabetes Association guidelines identify Asians as a high-risk population for GDM. [Diabetes Care 2000 Jan;23 Suppl 1:S77-9] A study of 2,797 Asian pregnancies found that the incidence of GDM was 10.6 percent for Vietnamese women, 9.2 percent for Chinese women and 8.6 percent for Filipino women. [Diabetes Care 2001 May;24(5):955-6]

GDM affects between 3 and 8 percent of pregnancies in Australia, according to Morrison, who is based at the New South Wales section of the charity Diabetes Australia.

With these women at substantially higher risk for developing diabetes this group represents an important target for disease prevention through lifestyle modification, she said.

“Often these women really only have contact with their GP after pregnancy and are no longer in the system of diabetes care necessarily, so it is over to the GP to help them make those changes and raise that awareness,” she said.