Estrogen administration and withdrawal in a model of hormone-simulated pregnancy lead to alterations in behavior and gene expression but do not induce depression-like phenotypes in mice.

Pregnancy and the post-partum period are associated with substantial fluctuations in hormone levels and are frequently associated with significant stress. Many individuals also experience affective disturbances during the peri­partum period, including anxiety, the 'baby blues,' and post-partum depression. However, the extent to which these affective changes result from rapidly altering hormone levels, increased stress, or the combination of both remains largely unknown. The current study sought to evaluate the consequences of pregnancy-like hormonal changes on behavior and gene expression in c57BL/6 mice in the absence of stress using a hormone-simulated pregnancy model. Our results reveal that animals receiving hormone injections to simulate the high levels of estrogen observed in late pregnancy and animals withdrawn from estrogen to mimic the rapid decline in this hormone following parturition both exhibit increased anxiety-like behavior compared to ovariectomized controls in the novel open field test. However, no other significant anxiety- or depression-like alterations were observed in either hormone-treated group compared to ovariectomized controls. Both hormone administration and estrogen withdrawal were shown to induce several significant alterations in gene expression in the bed nucleus of the stria terminalis and the paraventricular nucleus of the hypothalamus. In contrast to the estrogen withdrawal hypothesis of post-partum depression, our results suggest that this method estrogen withdrawal following hormone-simulated pregnancy in the absence of stress does not induce phenotypes consistent with post-partum depression in c57BL/6 mice. However, given that estrogen withdrawal does lead to significant gene expression changes in two stress-sensitive brain regions, it remains possible that estrogen withdrawal could still contribute to affective dysregulation in the peri-partum period by influencing susceptibility to stress. Future research is required to evaluate this possibility.

Factors Associated With Postpartum Smoking Relapse Among Women Who Quit in Early Pregnancy: The Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study.

BACKGROUND: While a wide range of predictors of postpartum smoking relapse have been suggested, population-based studies have rarely examined these factors exclusively among women who quit in early pregnancy. Furthermore, workplace secondhand smoke (SHS) exposure has never been examined. METHODS: We analyzed data from 10,466 pregnant women who participated in the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. Age, education, parity, breastfeeding, postpartum depression, SHS exposure at home, and SHS exposure at work (not working, working without SHS exposure, working with SHS exposure) were evaluated as possible predictors. Multiple logistic regression analyses were conducted to examine the associations between these factors and smoking relapse by 1 year postpartum among women who quit in early pregnancy. Analyses stratified by SHS exposure at home were also conducted. RESULTS: About one-fourth of early-pregnancy quitters had relapsed into smoking by 1 year postpartum. Lower education, multiparity, not breastfeeding, postpartum depression, and SHS exposure at home were associated with increased risks of smoking relapse. Working with SHS exposure was associated with an increased risk of smoking relapse; the multivariate-adjusted odds ratios of working without SHS exposure and working with SHS exposure compared with not working were 1.14 (95% confidence interval [CI], 0.82-1.59) and 2.18 (95% CI, 1.37-3.46), respectively. The significant association of workplace SHS exposure was observed only among women without SHS exposure at home. CONCLUSION: SHS exposure at work, as well as education, multiparity, breastfeeding, postpartum depression, and SHS exposure at home were associated with postpartum smoking relapse among early-pregnancy quitters.

Prenatal Exposure to Bisphenols and Phthalates and Postpartum Depression: The Role of Neurosteroid Hormone Disruption.

CONTEXT: Postpartum depression (PPD) is a serious psychiatric disorder. While causes remain poorly understood, perinatal sex hormone fluctuations are an important factor, and allopregnanolone in particular has emerged as a key determinant. Although synthetic environmental chemicals such as bisphenols and phthalates are known to affect sex hormones, no studies have measured allopregnanolone and the consequences of these hormonal changes on PPD have not been interrogated. OBJECTIVE: To investigate associations of repeated measures of urinary bisphenols and phthalates in early and midpregnancy with serum pregnenolone, progesterone, allopregnanolone, and pregnanolone concentrations in midpregnancy and PPD symptoms at 4 months postpartum. METHODS: Prospective cohort study of 139 pregnant women recruited between 2016 and 2018. Bisphenols and phthalates were measured in early and midpregnancy urine samples. Serum sex steroid hormone concentrations were measured in midpregnancy. PPD was assessed at 4 months postpartum using the Edinburgh Postnatal Depression Scale (EPDS). Multiple informant models were fit using generalized estimating equations. Serum levels of allopregnanolone, progesterone, pregnanolone, and pregnenolone were examined as log-transformed continuous variables. PPD symptoms were examined as continuous EPDS scores and dichotomously with scores ≥10 defined as PPD. RESULTS: Di-n-octyl phthalate (DnOP) and diisononyl phthalate (DiNP) metabolites were associated with reduced progesterone concentrations. Log-unit increases in ∑DnOP and ∑DiNP predicted 8.1% (95% CI -15.2%, -0.4%) and 7.7% (95% CI -13.3%, -1.7%) lower progesterone, respectively. ∑DnOP was associated with increased odds of PPD (odds ratio 1.48; 95% CI 1.04, 2.11). CONCLUSION: Endocrine disrupting chemicals may influence hormonal shifts during pregnancy as well as contribute to PPD.

Antidepressant-like effects of omega-3 fatty acids in postpartum model of depression in rats.

Postpartum depression (PPD) is a psychiatric disorder that occurs in 10-15% of childbearing women. It is hypothesized that omega-3 fatty acids, which are components of fish oil, may attenuate depression symptoms. In order to examine this hypothesis, the animal model of postpartum depression was established in the present study. Ovariectomized female rats underwent hormone-simulated pregnancy (HSP) regimen and received progesterone and estradiol benzoate or vehicle for 23 days, mimicking the actual rat's pregnancy. The days after hormone termination were considered as the postpartum period. Forced feeding of menhaden fish oil, as a source of omega-3, with three doses of 1, 3, and 9g/kg/d, fluoxetine 15mg/kg/d, and distilled water 2ml/d per rat started in five postpartum-induced and one vehicle group on postpartum day 1 and continued for 15 consecutive days. On postpartum day 15, all groups were tested in the forced swimming test (FST) and open field test (OFT), followed by a biochemical assay. Results showed that the postpartum-induced rats not treated with menhaden fish oil, exhibited an increase in immobility time seen in FST, hippocampal concentration of corticosterone and plasmatic level of corticosterone, and pro-inflammatory cytokines. These depression-related effects were attenuated by supplementation of menhaden fish oil with doses of 3 and 9g/kg. Moreover, results of rats supplemented with menhaden fish oil were comparable to rats treated with the clinically effective antidepressant, fluoxetine. Taken together, these results suggest that menhaden fish oil, rich in omega-3, exerts beneficial effect on postpartum depression and decreases the biomarkers related to depression such as corticosterone and pro-inflammatory cytokines.

Estradiol modulates anhedonia and behavioral despair in rats and negative affect in a subgroup of women at high risk for postpartum depression.

In an effort to address inconsistencies in the literature, we tested a cross-species estrogen withdrawal model of postpartum depression (PPD) with a series of rodent experiments and a prospective, naturalistic human study. All rats were ovariectomized prior to experimentation. The first rat experiment examined the effects of low- and high-dose estradiol administration and withdrawal on lateral-hypothalamic self-stimulation, a behavioral index of anhedonia, in experimental (n=7) and vehicle-only control animals (n=7). The second rat experiment examined the effects of high-dose estradiol withdrawal on activity and immobility during the forced swim test, an index of behavioral despair, in a separate group of experimental (n=8) and vehicle-only control animals (n=8). In the human study, women with (n=8) and without (n=12) a history of PPD completed mood ratings and collected saliva samples (to assess estradiol levels) daily during the third trimester of pregnancy through 10 days postpartum. The presence of PPD was assessed at one month postpartum. In the animal studies, rats in the estradiol withdrawal group demonstrated significantly greater immobility and less swimming than controls. Estradiol withdrawal resulted in reduced responding for electrical stimulation (multiple intensities) relative to estradiol administration. In the human study, there was no significant association between estradiol and negative affect among women with or without a history of PPD. However, there was a correlation between daily estradiol levels and negative affect in the women with incident PPD at one month postpartum. Despite important cross-species differences, both the rat and human studies provided evidence of the effects of estradiol on perinatal depressive symptoms.

Ovarian hormone withdrawal-induced "depression" in female rats.

Approximately 15% of child-bearing women develop postpartum depression (PPD), and many women with PPD experience anxious symptoms. It has been proposed that PPD is precipitated by the dramatic decline in reproductive hormones that occurs just after childbirth. To examine this hypothesis, ovariectomized female Sprague-Dawley rats underwent a hormone-simulated pregnancy (HSP) regimen; during the subsequent hormone withdrawal period, rats were tested in the forced swim test or elevated plus-maze, animal models of depression and anxiety, respectively. The HSP regimen consisted of injections with progesterone and escalating doses of estradiol benzoate for 22 days; control rats received daily vehicle injections. One, two, four or seven days after the last hormone injection, separate groups of rats were tested once on either the forced swim test or the elevated plus-maze. To examine any hormone withdrawal-induced changes in activity levels, spontaneous locomotor activity was measured at the same time points. At 2 and 4 days after the last hormone injection, HSP-treated females displayed significant increases in immobility relative to vehicle-treated females in the forced swim test. Behavior on the elevated plus-maze did not differ between the HSP and control groups at any of the withdrawal time points. There were also no differences in spontaneous locomotor activity between the HSP and control females at any of the withdrawal time points. The results of this study suggest that postpartum hormone withdrawal may contribute to depressive symptoms experienced after giving birth, and that the HSP-hormone withdrawal protocol may provide a useful animal model of PPD.

Estradiol alleviates depressive-like symptoms in a novel animal model of post-partum depression.

The effect of hormone withdrawal following hormone-simulated "pregnancy" on "depressive-like behavior" in the Forced Swim Test (FST) was investigated in female Long-Evans rats. Females were randomly assigned to "pregnant", "pregnant"+estradiol benzoate (EB), and control groups. Both the "pregnant" and "pregnant"+EB groups received daily injections of the hormones estradiol and progesterone to simulate the 23-day gestational period in the rat. However, the "pregnant"+EB group continued to receive daily estradiol injections after "pregnancy". All groups were tested 48 h after the last injection of the pregnancy period in the FST and subsequently in the Open Field Test (OFT). Results revealed that the "pregnant" rats exhibited significantly increased immobility and decreased struggling and swimming behaviors as compared to the "pregnant"+EB and control groups. These findings could not be explained by an overall depression in general locomotor activity among "pregnant" rats, as the "pregnant" rats made more area crossings in the OFT. Thus "pregnant" rats exhibited behaviors consistent with "depressive-like" symptoms "post-partum" (after their hormone regime was discontinued). Continual treatment with high levels of estradiol in the "pregnant"+EB group, however, reversed the exhibition of these behaviors. These results imply that withdrawal from chronic high levels of pregnancy-associated hormones (estradiol and progesterone) can produce depressed symptomology in rodents, which can be prevented by prolonging exposure to high levels of estradiol through the post-partum period. These findings are the first demonstration of "depressive-like" symptoms in a rodent model of post-partum pregnancy and the ability of high levels of estradiol to attenuate these "depressive-like" symptoms.

A double-blind randomised placebo controlled trial of postnatal norethisterone enanthate: the effect on postnatal depression and serum hormones.

OBJECTIVES: To determine the effect of postnatal administration of the long-acting progestogen contraceptive, norethisterone enanthate, on postnatal depression and on serum hormone concentrations, and their association with depression. DESIGN: Double-blind randomised placebo-controlled trial. SETTING: A tertiary care hospital in Johannesburg, South Africa. POPULATION Postnatal women using a non-hormonal method of contraception (n = 180). METHODS: Random allocation within 48 hours of delivery to norethisterone enanthate by injection, or placebo. MAIN OUTCOME MEASURES: Depression scores in the three months postpartum as rated by the Montgomery-Asberg Depression Rating Scale (MADRS) and the Edinburgh Postnatal Depression Scale (EPDS); 2. serum 17beta-oestradiol, progesterone, testosterone and the 17beta-oestradiol:progesterone ratio at six weeks postpartum. RESULTS: There was a chance excess of caesarean section deliveries in the progestogen group. Mean depression scores were significantly higher in the progestogen group than in the placebo group at six weeks postpartum (mean MADRS score 8.3 vs 4.9; P = 0.0111; mean EPDS score 10.6 vs 7.5; P = 0.0022). Mean serum 17beta-oestradiol and progesterone concentrations were significantly lower in the progestogen group compared with the placebo group at six weeks postpartum. There were no correlations between any of the hormone parameters and depression at six weeks except in the formula feeding subgroup of the placebo group, where formula feeding and 17beta-oestradiol concentrations were positively associated with depression. CONCLUSIONS: Long-acting norethisterone enanthate given within 48 hours of delivery is associated with an increased risk of developing postnatal depression and causes suppression of endogenous ovarian hormone secretion.