This population-based cohort study «Mantel Ä, Hirschberg AL, Stephansson O. Associatio...»1 included all singleton births included in the Swedish Medical Birth Register from January 1, 2003, to December 31, 2014. A total of 7542 women with eating disorders were compared with 1 225 321 women without eating disorders. Statistical analysis was performed from January 1, 2018, to April 30, 2019. Via linkage with the national patient register, women with eating disorders were identified and compared with women free of any eating disorder. Eating disorders were further stratified into active or previous disease based on last time of diagnosis.
The risk of adverse pregnancy outcomes (hyperemesis, anemia, preeclampsia, and antepartum hemorrhage), the mode of delivery (cesarean delivery, vaginal delivery, or instrumental vaginal delivery), and the neonatal outcomes (preterm birth, small and large sizes for gestational age, Apgar score <7 at 5 minutes, and microcephaly) were calculated using Poisson regression analysis to estimate risk ratios (RRs). Models were adjusted for age, parity, smoking status, and birth year.
There were 2769 women with anorexia nervosa (mean [SD] age, 29.4 [5.3] years), 1378 women with bulimia nervosa (mean [SD] age, 30.2 [4.9] years), and 3395 women with an eating disorder not otherwise specified (EDNOS; mean [SD] age, 28.9 [5.3] years), and they were analyzed and compared with 1 225 321 women without eating disorders (mean [SD] age, 30.3 [5.2] years). Women with eating disorders, all subtypes, were at increased risk of a preterm birth (anorexia nervosa: RR, 1.6 [95 % CI, 1.4-1.8]; bulimia nervosa: RR, 1.3 [95 % CI, 1.0-1.6]; and EDNOS: RR, 1.4 [95 % CI, 1.2-1.6]) and of delivering neonates with microcephaly (anorexia nervosa: RR, 1.9 [95 % CI, 1.5-2.4]; bulimia nervosa: RR, 1.6 [95 % CI, 1.1-2.4]; EDNOS: RR, 1.4 [95 % CI, 1.2-1.9]).
In this register-based case-control follow-up study by Linna et al. «Linna MS, Raevuori A, Haukka J, ym. Pregnancy, obs...»2, female patients (n = 2257) who were treated at the Eating Disorder Clinic of Helsinki University Central Hospital from 1995-2010 were compared with unexposed women from the population (n = 9028). Register-based information on pregnancy, obstetric, and perinatal health outcomes and complications were acquired for all singleton births during the follow-up period among women with broad anorexia nervosa (AN; n = 302 births), broad bulimia nervosa (BN; n = 724), binge eating disorder (BED; n = 52), and unexposed women (n = 6319).
Women with AN and BN gave birth to babies with lower birthweight compared with unexposed women (AN: mean, 3302 ± 562 g; adjusted p<0.001, BN: mean, 3464 ±563 g; adjusted p = 0,037, unexposed women: mean, 3520 ± 539 g), but the opposite was observed in women with BED (mean, 3812 ± 519 g; adjusted p<0.001).
Maternal AN was related to slow fetal growth (4.64 %, in AN vs. 1.93 % in unexposed women, adjusted OR 2.59, 95 % CI 1.43-4.71), very premature birth (0.99 % in AN vs. 0.29 % in unexposed women, adjusted OR 4.59, 95 % CI 1.25-16.87), small for gestational age (4.30 % in AN vs. 2.10 % in unexposed women, adjusted OR 2.20, 95 % CI 1.23-3.93), and low birthweight (6.31 % in AN vs. 3.19 % in unexposed women, adjusted OR 2.16, 95 % CI 1.30-3.58). BED was associated positively with birth of large-for-gestational-age infants (9.62 % in BED vs. 2.45 % in unexposed women, adjusted OR 4.32, 95 % CI 1.64-11.36). Gestational age was the lowest among women with AN and the highest among women with BED.
This study by Micali et al. «Micali N, Stemann Larsen P, Strandberg-Larsen K, y...»3 attempted to investigate whether eating disorders are associated with lower size at birth, symmetric growth restriction, and preterm birth; and whether pregnancy smoking explains the association between anorexia nervosa and fetal growth.
The longitudinal population-based cohort study looked at a female study population from the Danish National Birth Cohort (n = 83 826). Women with anorexia nervosa (n = 1609), bulimia nervosa (n = 1693) and both (anorexia + bulimia nervosa, n = 634) were compared with unexposed women (n = 76 724) (women with exposure data and singletons n = 80 660) using crude and adjusted linear and logistic regression models.
The study used data on self-reported pre-pregnancy BMI and recency of onset to determine whether maternal AN was active or past: given that underweight is a diagnostic criterion of AN, all women who self-reported having suffered from AN lifetime and who had a BMI < 18.5 were classified as having active AN (n = 174, 0.23 %), women with lifetime AN who had a BMI > 18.5 pre-pregnancy (n = 1415, 1.84 %), were classified as past AN. Women with active AN reported onset of the disorder closer to enrolment.
Main outcome measures weresize at birth (birthweight, length, head and abdominal circumference and placental weight); gestational age; small- and large-for-gestational-age (SGA, LGA); ponderal index, abdominal/head circumference.
Lifetime anorexia nervosa and lifetime anorexia + bulimia nervosa were prospectively associated with restricted fetal growth and higher odds of SGA [respectively, OR = 1.6 [95 % CI 1.3-1.8] and OR = 1.5 [95 % CI 1.2-1.9)] compared with unexposed women. Active anorexia nervosa was associated with lower birthweight, length, head and abdominal circumference, ponderal index, higher odds of SGA [OR = 2.90 (95 % 1.98-4.26)] and preterm birth [OR = 1.77 (95 % CI 1.00-3.12)] compared with unexposed women. Pregnancy smoking only partly explained the association between anorexia nervosa and adverse fetal outcomes.
Maternal anorexia nervosa (both active and past) is associated with lower size at birth and symmetric growth restriction, with evidence of worse outcomes in women with active disorder.
This study by Eik-Nes et al. «Eik-Nes TT, Horn J, Strohmaier S, ym. Impact of ea...»4 attempted to investigate pregnancy and obstretric outcomes in eating disorders. Data from a hospital patient register and a population-based study (The HUNT Study) were linked to the Medical Birth Registry in Norway. Register based information of obstetric complications (preeclampsia, preterm birth, perinatal deaths, small for gestational age (SGA), large for gestational age (LGA), Caesarean sections, and 5-min Apgar score) were acquired for 532 births of women with ED and 43,657 births of non-ED women. Multivariable regression in generalized estimating equations was used to account for clusters within women as they contributed multiple births to the dataset.
After adjusting for parity, maternal age, marital status, and year of delivery, lifetime history of anorexia nervosa was associated with increased odds of having offspring who were SGA (Odds ratio (OR) 2.7, 95 % Confidence Interval (CI) 1.4-5.2). Women with a lifetime history of bulimia nervosa had higher odds of having a Caesarian section (OR 1.7 95 % CI 1.1-2.5). Women with EDNOS/sub-threshold ED had a higher likelihood of having a low Apgar score at 5 min (OR 3.1, 95 % CI 1.1-8.8).
The study by Ante et al. «Ante Z, Luu TM, Healy-Profitós J, ym. Pregnancy ou...»5 attempted to estimate whether maternal hospitalization for anorexia nervosa before or during pregnancy is associated with an elevated risk of adverse maternal and infant birth outcomes.
The researchers performed a retrospective cohort study of 2,134,945 pregnancies in Quebec, Canada, from 1989 to 2016. The main exposure measure was anorexia nervosa requiring hospital treatment before or during pregnancy. The women with anorexia nervosa had 1910 births. Outcome measures included stillbirth, preterm birth, low birth weight, small-for-gestational age birth, preeclampsia, gestational diabetes, cesarean delivery, and other pregnancy disorders.
Compared with no hospitalization, anorexia nervosa hospitalization was associated with 1.32 times the risk of preterm birth (95 % CI 1.13-1.55), 1.69 times the risk of low birth weight (95 % CI 1.44-1.99), and 1.52 times the risk of small-for-gestational age birth (95 % CI 1.35-1.72). The associations with low birth weight and small-for-gestational age birth were more prominent in women hospitalized for anorexia nervosa during pregnancy or within 2 years of delivery.
Solmi et al. «Solmi F, Sallis H, Stahl D, ym. Low birth weight i...»6 conducted a systematic review and meta-analysis on birth weight of babies born to mothers with anorexia nervosa. PubMed, Embase, and PsychInfo were searched for studies comparing the mean birth weight of babies delivered by mothers with (a history of) anorexia nervosa against those of healthy mothers. Studies were excluded from the meta-analysis if not presenting data from an unexposed comparison group and if using multiple eating disorders as exposure without presenting individual results. Fourteen studies were included in the systematic review and 9 in the meta-analysis, undertaken between 1999 and 2012 in Denmark, the Netherlands, New Zealand, Norway, Sweden, and the United Kingdom. Birth weights were standardized by dividing the difference in mean birth weight by the pooled standard deviation (equivalent to Cohen's d). Results showed a standardized mean difference of -0.19 kg (95 % confidence interval: -0.25, -0.15; P = 0.01) in the birth weight of children of mothers with anorexia nervosa, and some bias in favor of papers presenting lower birth weight results for exposed mothers was detected. However, the small power of the analysis due to the small number of available studies and, thus, chance could partially account for this result.