Patients with resolution of low-lying placenta and placenta previa remain at increased risk of postpartum hemorrhage.

OBJECTIVE: To determine whether women who experience resolution of low placentation (low-lying placenta or placenta previa) are at increased risk of postpartum hemorrhage compared to those with normal placentation throughout pregnancy. METHODS: This was a retrospective cohort study of women who delivered at Mount Sinai Hospital between 2015 and 2019, and who were diagnosed with low-lying placenta or placenta previa on transvaginal ultrasound at the time of the second-trimester anatomical survey, with resolution of low placentation on subsequent ultrasound examination. Women undergoing second-trimester anatomical survey who had normal placentation on transvaginal ultrasound 3 days before or after the cases were randomly identified for comparison. The primary outcome was the rate of postpartum hemorrhage. Secondary outcomes included the need for a blood transfusion, use of additional uterotonic medication, the need for additional procedures to control bleeding, and maternal admission to the intensive care unit. Outcomes were assessed using a multivariable logistic regression model. RESULTS: A total of 1256 women were identified for analysis, of whom 628 had resolved low placentation and 628 had normal placentation. Women with resolved low placentation, compared to those with normal placentation throughout pregnancy, had significantly higher mean age (33.0 ± 5.4 years vs 31.9 ± 5.5 years; P < 0.01) and lower mean body mass index at delivery (27.9 ± 5.5 kg/m2 vs 30.2 ± 5.7 kg/m2 ; P < 0.01), and were more likely to have undergone in-vitro fertilization, be of non-Hispanic white race, have posterior placental location (all P < 0.01) and have private/commercial health insurance (P = 0.04). Patients with resolved low placentation vs normal placentation had greater odds of postpartum hemorrhage (adjusted odds ratio (aOR), 3.5 (95% CI, 2.0-6.0); P < 0.01), use of additional uterotonic medication (aOR, 2.2 (95% CI, 1.5-3.1); P < 0.01) and increased rates of additional procedures to control bleeding (aOR, 4.0 (95% CI, 1.3-11.9); P = 0.01). CONCLUSION: Despite high rates of resolution of low-lying placenta and placenta previa by term, women with resolved low placentation remain at increased risk of postpartum hemorrhage compared to those with normal placentation throughout pregnancy. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Somatic and Neuroendocrine Changes in Response to Chronic Corticosterone Exposure During Adolescence in Male and Female Rats.

Prolonged stress and repeated activation of the hypothalamic-pituitary-adrenal axis can result in many sex-dependent behavioural and metabolic changes in rats, including alterations in feeding behaviour and reduced body weight. In adults, these effects of stress can be mimicked by corticosterone, a major output of the hypothalamic-pituitary-adrenal axis, and recapitulate the stress-induced sex difference, such that corticosterone-treated males show greater weight loss than females. Similar to adults, chronic stress during adolescence leads to reduced weight gain, particularly in males. However, it is currently unknown whether corticosterone mediates this somatic change and whether additional measures of neuroendocrine function are affected by chronic corticosterone exposure during adolescence in a sex-dependent manner. Therefore, we examined the effects of non-invasively administered corticosterone (150 or 300 µg/ml) in the drinking water of male and female rats throughout adolescent development (30-58 days of age). We found that adolescent animals exposed to chronic corticosterone gain significantly less weight than controls, which may be partly mediated by the effects of corticosterone on food consumption, fluid intake and gonadal hormone function. Our data further show that, despite similar circulating corticosterone levels, males demonstrate a greater sensitivity to these changes than females. We also found that Npy1 and Npy5 receptor mRNA expression, genes implicated in appetite regulation, was significantly reduced in the ventral medial hypothalamus of corticosterone-treated males and females compared to controls. Finally, parameters of gonadal function, such as plasma sex steroid concentrations and weight of reproductive tissues, were reduced by adolescent corticosterone treatment, although only in males. The data obtained in the present study indicate that chronic corticosterone exposure throughout adolescent development results in significant and sex-dependent somatic and neuroendocrine changes, and the results also provide an experimental framework for further investigating the impact of corticosterone on metabolic and neuroendocrine function during adolescence.