Women with Postpartum Weight Retention Have Delayed Wake Times and Decreased Sleep Efficiency During the Perinatal Period: A Brief Report.

OBJECTIVE: This study assessed sleep and circadian rhythms across the perinatal period in new mothers with and without postpartum weight retention (PPWR). METHODS: Weight was measured at 2 and 16 weeks postpartum in 21 women with previous major depression or bipolar disorder (mean age 29.5±4.7 years) who self-reported pre-pregnancy weight during third trimester. Wrist actigraphy was acquired at 33 weeks gestation and postpartum weeks 2, 6, and 16. Circadian phase was measured at 33 weeks gestation and 6 weeks postpartum. The Horne-Östberg Morningness-Eveningness Questionnaire and Pittsburgh Sleep Quality Inventory were completed during third trimester. Women were classified as PPWR+ if weight at 16 weeks postpartum exceeded pre-pregnancy weight by ≥5kg. RESULTS: Compared to pre-pregnancy, average weight gain (±SD) was 6.3±8.8 kg at 2 weeks postpartum and 5.2±8.5 kg at 16 weeks postpartum. ANOVA showed that PPWR+ women (n=8, 38%) had later sleep offset times and lower sleep efficiencies than PPWR- women at all time points and were more likely to report snoring during pregnancy. CONCLUSIONS: Data from this small sample showed that women with PPWR had more disturbed sleep and later wake times and were more likely to report symptoms of sleep-disordered breathing. Future work in larger samples should examine whether interventions to improve sleep during pregnancy decreases PPWR.

Larval and nurse worker control of developmental plasticity and the evolution of honey bee queen-worker dimorphism.

Social evolution in honey bees has produced strong queen-worker dimorphism for plastic traits that depend on larval nutrition. The honey bee developmental programme includes both larval components that determine plastic growth responses to larval nutrition and nurse components that regulate larval nutrition. We studied how these two components contribute to variation in worker and queen body size and ovary size for two pairs of honey bee lineages that show similar differences in worker body-ovary size allometry but have diverged over different evolutionary timescales. Our results indicate that the lineages have diverged for both nurse and larval developmental components, that rapid changes in worker body-ovary size allometry may disrupt queen development and that queen-worker dimorphism arises mainly from discrete nurse-provided nutritional environments, not from a developmental switch that converts variable nutritional environments into discrete phenotypes. Both larval and nurse components have likely contributed to the evolution of queen-worker dimorphism.