Concentrations of the hormone leptin, which is produced by adipose tissue, increase with increasing BMI, whereas leptin sensitivity often declines with higher BMI. Thus, altered leptin signaling may play a role in reproductive health risks observed with increasing BMI, which include later onset and slow progression of labor. Conflicting evidence from clinical, animal and in vitro studies have suggested that leptin either promotes or inhibits labor. We hypothesized that serum leptin concentrations or serum leptin: body mass index (BMI) ratios in women may be associated with the initiation and progression of labor. Following informed consent, serum samples were collected from 90 women with singleton pregnancies at the time of routine glucose-challenge testing, for measurement of leptin. The potential influence of leptin on gestation length and cervical dilation timing were examined by multiple linear regression. Data were analyzed from 63 participants who met exclusion and inclusion criteria. Leptin concentrations (log-transformed) at 24–28 weeks gestation were not significantly correlated with first trimester BMI . Log serum leptin and leptin: BMI ratio each were significantly associated with shorter total gestation length in uncomplicated, term pregnancies. In contrast, the mid-pregnancy leptin concentrations were not associated with progression of labor, assessed by cervical dilation over time. The association between higher serum leptin and shorter gestation length is consistent with the hypothesis that leptin promotes, or is permissive for, the onset of labor.

The vaginal contraceptive ring is very effective and user dependent. In this article, we will discuss the different types of vaginal contraceptive rings, namely, the etonogestrel/ethinyl estradiol (ENG/EE) ring (NuvaRing, Merck, Rahway, NJ, USA) and the segesterone acetate (SA)/EE (Annovera, Mayne Pharma, Raleigh, NC, USA) ring. The details of dosing and administration, indications, advantages, disadvantages, and cost-effectiveness are presented. This literature review was conducted using PubMed and Google Scholar. The search terms included ‘vaginal contraceptive ring’, ‘etonogestrel/ethinyl estradiol ring’, and ‘segesterone acetate/ethinyl estradiol ring’. The search was then sorted by year from 2000 until present, and the most recent articles were reviewed. The purpose of this article is to provide a comprehensive reference on the two vaginal contraceptive rings widely used in the United States for clinicians to guide management. Both vaginal contraceptive rings are combination of hormonal contraceptives that suppress ovulation and create physiologic conditions unfavorable for pregnancy. The ENG/EE ring is designed to be replaced monthly, while the SA/EE ring is a single device used over the course of 1 year. Common side effects of both devices include headaches, nausea, vomiting, and vaginitis. Serious adverse reactions can occur with the vaginal contraceptive rings including venous thromboembolism, psychiatric events, and hypersensitivity. Both devices are contraindicated in patients at high risk for arterial or venous thrombotic events, patients with a history of breast cancer or other estrogen/progesterone cancers, and patients with severe liver disease. Overall, the vaginal contraceptive ring is well tolerated and liked by patients. Patients should be well counseled on known severe adverse reactions. The vaginal contraceptive ring is more expensive than other forms of contraception and this should be an important point of discussion with patients.