Prenatal Issues in Anorexia Nervosa
Two large population-based studies have found that women with current anorexia nervosa have an earlier age of pregnancy compared with women in the general population without eating disorders.[19,20] Further investigation in the Norwegian Mother and Child Cohort Study (MoBa; including 62,060 births in Norway) found that the risk of having an unplanned pregnancy was significantly increased in women with current anorexia nervosa in the 6 months before pregnancy, with 50% reporting that their pregnancy was unplanned compared with only 18.9% in the referent group. In addition, women with anorexia nervosa were significantly more likely to report a past induced abortion than the referent group (24.2 vs 14.6%).
While the explanation for this finding requires additional study, the authors hypothesize that the absence or irregularity of menstruation in these women may lead them to the belief that conception is unlikely and that there is less need for adherence to guidelines for proper contraceptive use. To our knowledge, there are currently no published studies evaluating fidelity of contraceptive use in women with anorexia nervosa.
This finding is particularly concerning, as unplanned pregnancies may decrease the opportunities these women have to establish critical nutritional and emotional support to help them manage the physical and psychological demands of pregnancy and motherhood.
Prenatal Eating Behavior
Remission of Eating Disorder Symptoms During Pregnancy Rigorous evaluation of the eating behaviors of women with anorexia nervosa during pregnancy is exceedingly difficult owing to the relatively low prevalence of the disorder in the general population (0.9%) and the difficulty of assessing the weight criterion for anorexia nervosa during pregnancy. Nevertheless, early retrospective investigations of clinical samples found some women with eating disorders (not solely anorexia nervosa) report temporary improvement in eating disorder symptomatology during pregnancy, with a resurgence of symptoms postpartum.
Three large prospective studies addressing eating behavior during pregnancy in women with eating disorders have replicated the findings of these early retrospective reports. In the MoBa cohort, remission rates during pregnancy across the eating disorder subtype were between 29 and 78%, although this study did not evaluate remission of anorexia nervosa specifically, owing to difficulty assessing the weight criterion during pregnancy. With respect to body-image concerns, cohort studies in both the UK and the USA found that concerns over shape and weight were seen to decrease during pregnancy in women with active eating disorders (not solely anorexia nervosa).[20,24,25]
Of note, approximately one-third of women struggling with eating disorders (including, but not limited to anorexia nervosa) believe that pregnancy could provide a means to recover from their disorder, even though they also report fear that their gestational weight gain will be out of their control. Many also report that they view gestational weight gain and a larger body size as more acceptable during pregnancy than under other circumstances.[22,26]
Relapse of Eating Disorder Symptoms During Pregnancy While some women may experience a remission from eating disorder symptoms during pregnancy, several studies report that women recovered from eating disorders experience relapses during pregnancy. A prospective study in Sweden that followed individuals with a past diagnosis of anorexia nervosa prior to pregnancy found that eight out of 24 women (33%) had a verified relapse of their eating disorder during pregnancy that led to contact with a psychologist or psychiatrist, and a UK study reported that women with past eating disorders (not solely anorexia nervosa) reported an increase in overall weight and shape concerns during pregnancy.
Disordered Eating Behaviors During Pregnancy Women with recent and past anorexia nervosa report very low use of laxatives and self-induced vomiting during pregnancy, but are more likely to engage in a high level of exercise (defined as greater than 1 h of moderate to vigorous activity daily) during pregnancy than nonobese women without eating disorders.
Women with anorexia nervosa before pregnancy are also more likely to smoke during pregnancy (37.1% compared with 9.2% in women without eating disorders). While concerns about weight and appetite control may be associated with this increase in smoking during pregnancy, a separate study found that individuals with eating disorders score higher on a scale of nicotine dependence than those without eating disorders, suggesting that giving up smoking during pregnancy may represent a greater challenge for these women.
There has been much debate in the literature as to the risk of hyperemesis gravidum (HG) during pregnancy in women with eating disorders.[10,27,29,30] When HG was defined as vomiting during pregnancy requiring hospitalization, women with purging-type eating disorders were not found to have statistically significant elevated odds of HG (1.9–3.8% of women with purging-type eating disorders and 1.3% of controls). However, when HG was identified by symptoms reported in medical records, but not necessarily that requiring hospitalization, women with past or current eating disorders had significantly increased risk of HG (67% of women with eating disorders and 13% of controls). In general, women with purging-type eating disorders are significantly more likely to report both pregnancy-related nausea and pregnancy-related vomiting than women without an eating disorder. Thus, while the increased risk of HG in women with eating disorders appears to depend on the stringency of the definition of HG used, women with purging-type eating disorders (including the binge–purge subtype of anorexia nervosa) are more likely to experience both nausea and vomiting during their pregnancy and should be closely monitored to ensure that the severity of these symptoms does not lead to inadequate weight gain and nutrition.
Weight Gain & Nutrition During Pregnancy In the Norwegian MoBa cohort, women with current anorexia nervosa before pregnancy gained significantly more weight and gained weight more quickly [Zerwas SC, Von Holle A, Perrin EM et al. Patterns of pregnancy and post-partum weight change in mothers with eating disorders from the Norwegian Mother and Child Cohort Study (MoBa); Submitted Manuscript] during pregnancy than women with no eating disorder (17.8 kg compared with 14.9 kg). Institute of Medicine guidelines recommend a weight gain of 12.7–18 kg for women with a BMI of less than 18.5, and thus weight gain of 17.8 kg may signal appropriate concern with adequate gestational weight during this critical time. Greater weight gain in women with anorexia nervosa during pregnancy could ensure that the nutritional demands of the developing fetus are met.[19,23,31,32] However, there is an additional need to examine the nutritional quality of food women with anorexia nervosa are consuming during this time.
Little is known about the nutritional status of women with anorexia nervosa at conception, during pregnancy and the postpartum period. Macronutrient composition for women with anorexia nervosa during pregnancy may be qualitatively different and include less protein and fat than women with no eating disorder.[31,33–35] However, even less is known about their micronutrient status. Although much attention has been paid to adequate folate in order to protect against neural tube defects, inadequate stores of micronutrients such as iron, B vitamins, vitamin A and iodine have also been linked to pregnancy outcomes and fetal neural development. Moreover, multiple micronutrient deficiencies during pregnancy and lactation may also have an additive effect. In the Norwegian MoBa cohort, approximately 44–75% women with current anorexia nervosa before pregnancy did take nutritional supplements during pregnancy, which included these important micronutrients. However, given their possibly nutritionally depleted status, it is unclear whether these supplements adequately met their and their child's nutritional needs.
Expert Rev of Obstet Gynecol. 2011;6(4):403-414. © 2011 Expert Reviews Ltd.
Cite this: Reproductive Issues in Anorexia Nervosa - Medscape - Aug 01, 2011.