Preconception sleep duration, sleep timing, and shift work in association with fecundability and live birth among women with a history of pregnancy loss

OBJECTIVE

To evaluate the associations between preconception sleep characteristics and shift work with fecundability and live birth.

DESIGN

Secondary analysis of the Effects of Aspirin in Gestation and Reproduction study, a preconception cohort.

SETTING

Four US academic medical centers.

PATIENT(S)

Women aged 18-40 with a history of 1-2 pregnancy losses who were attempting to conceive again.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURES(S)

We evaluated baseline, self-reported sleep duration, sleep midpoint, social jetlag, and shift work among 1,228 women who were observed for ≤6 cycles of pregnancy attempts to ascertain fecundability. We ascertained live birth at the end of follow up via chart abstraction. We estimated fecundability odds ratios (FORs) using discrete, Cox proportional hazards models and risk ratios (RRs) for live birth using log-Poisson models.

RESULT(S)

Sleep duration ≥9 vs. 7 to <8 hours (FOR: 0.81, 95% confidence interval [CI], 0.61; 1.08), later sleep midpoints (3rd tertile vs. 2nd tertile: FOR: 0.85; 95% CI, 0.69, 1.04) and social jetlag (continuous per hour; FOR: 0.93, 95% CI: 0.86, 1.00) were not associated with reduced fecundability. In sensitivity analyses, excluding shift workers, sleep duration ≥9 vs. 7 to <8 hours (FOR: 0.62; 95% CI, 0.42; 0.93) was associated with low fecundability. Night shift work was not associated with fecundability (vs. non-night shift work FOR: 1.17, 95% CI, 0.96; 1.42). Preconception sleep was not associated with live birth.

CONCLUSION(S)

Overall, there does not appear to be a strong association between sleep characteristics, fecundability, and live birth. Although these findings may suggest weak and imprecise associations with some sleep characteristics, our findings should be evaluated in larger cohorts of women with extremes of sleep characteristics.

CLINICAL TRIAL REGISTRATION NUMBER

Clinicaltrials.gov NCT00467363.

Burden of sleep disturbance in non-Hispanic Black pregnant women

STUDY OBJECTIVES

Non-Hispanic Black pregnant women disproportionately experience poor perinatal outcomes compared to other racial/ethnic groups. Sleep disruption has emerged as a risk factor for adverse pregnancy outcomes but there are limited data in minority pregnant women. We examined the prevalence of habitual snoring and its timing of onset with several key sleep-wake disturbances and their associations with perinatal outcomes in a cohort of non-Hispanic Black pregnant women.

METHODS

Third trimester non-Hispanic Black pregnant women were recruited from a large, academic medical center and screened for habitual snoring - and its timing relative to pregnancy - sleep quality, symptoms of insomnia, excessive daytime sleepiness, as well as daytime function. Clinical diagnoses of hypertensive disorders of pregnancy were obtained along with delivery outcomes.

RESULTS

In 235 women the vast majority (80%) reported three or more sleep-wake disturbances, and almost half had at least five disturbances. Sixteen percent endorsed pre-pregnancy snoring and 20% pregnancy-onset snoring. Women with pregnancy-onset snoring had significantly increased odds of poor sleep quality aOR 8.2, trouble staying asleep aOR 3.6, waking up too early aOR 2.7, excessive daytime sleepiness aOR 2.3, and poor daytime function aOR 8.7 but no relationship with perinatal outcomes. In contrast, pre-pregnancy snoring was related to chronic hypertension, pre-term delivery and fetal growth restriction; aOR 2.6, aOR 2.8, and aOR 5.1 respectively.

CONCLUSIONS

Sleep-wake disturbances confer a significant burden to pregnant non-Hispanic Black women, an infrequently studied yet disproportionately affected population. Contributions of maternal sleep to racial disparities in perinatal health should be a priority for public health research.

The association between obstructive sleep apnea risk and cognitive disorders: a population-based study

STUDY OBJECTIVES

To examine the association between OSA risk and cognitive disorders among US adults.

METHODS

Data from the 2016 wave of the Health and Retirement Study (HRS) were utilized. Probable OSA cases were identified with survey items that resembled critical elements of a clinically validated OSA screen (STOP-Bang questionnaire). Weighted prevalence of cognitive impairment not dementia (CIND) and dementia among individuals with and without probable OSA were assessed. Cross-sectional analyses of associations between OSA risk and cognitive outcomes, along with effect modification by race and ethnicity, were estimated using imputed data.

RESULTS

Of the 20,910 HRS participants, 60% had probable OSA. CIND and dementia were more common among adults with probable OSA as compared to those without (12.7% vs. 8.0% for CIND; 3.2% vs 2.0% for dementia). Probable OSA was associated with CIND (OR=1.22, 1.08-1.37) and dementia (OR=1.27, 1.04-1.54). Race/ethnicity significantly modified the association between probable OSA and CIND, with a higher risk for CIND in Whites (OR=1.35, 1.17-1.57) as compared to non-Whites (OR=0.98, 0.81-1.19).

CONCLUSIONS

CIND and dementia are more common among older adults who are at high risk for OSA, as compared to low-risk individuals. These data highlight the importance of consideration of OSA risk in large-scale studies of OSA and cognitive disorders.

Relationships of beverage consumption and actigraphy-assessed sleep parameters among urban-dwelling youth from Mexico

OBJECTIVE

To examine whether usual beverage intake was associated with sleep timing, duration and fragmentation among adolescents.

DESIGN

Usual beverage intake was assessed with a FFQ. Outcomes included sleep duration, midpoint (median of bed and wake times) and fragmentation, assessed with 7-d actigraphy. Sex-stratified linear regression was conducted with sleep characteristics as separate outcomes and quantiles of energy-adjusted beverage intake as exposures, accounting for age, maternal education, physical activity and smoking.

SETTING

Mexico City.

PARTICIPANTS

528 adolescents residing in Mexico City enrolled in a longitudinal cohort.

RESULTS

The mean age (sd) was 14·4 (2·1) years; 48 % were male. Among males, milk and water consumption were associated with longer weekday sleep duration (25 (95 % CI 1, 48) and 26 (95 % CI 4, 47) more minutes, in the 4th compared to the 1st quartile); and higher 100 % fruit juice consumption was related to earlier weekday sleep timing (-22 (95 % CI -28, 1) minutes in the 1st compared to the last quantile; P = 0·03). Among females, soda was associated with higher sleep fragmentation (1·6 (95 % CI 0·4, 2·8) % in the 4th compared to the 1st), and coffee/tea consumption was related to shorter weekend sleep duration (-23 (95 % CI -44, 2) minutes in the 4th compared to the 1st).

CONCLUSIONS

Among females, adverse associations with sleep were observed for caffeinated drinks, while males with higher consumption of healthier beverage options (water, milk and 100 % juice) had evidence of longer and earlier-timed sleep. Potential mechanisms involving melatonin and tryptophan should be further investigated.

Obstructive Sleep Apnea Treatment and Dementia Risk in Older Adults

STUDY OBJECTIVES

To examine associations between PAP therapy, adherence and incident diagnoses of Alzheimer's disease (AD), mild cognitive impairment (MCI), and dementia not-otherwise-specified (DNOS) in older adults.

METHODS

This retrospective study utilized Medicare 5% fee-for-service claims data of 53,321 beneficiaries, aged 65+, with an OSA diagnosis prior to 2011. Study participants were evaluated using ICD-9 codes for neurocognitive syndromes [AD(n=1,057), DNOS(n=378), and MCI(n=443)] that were newly-identified between 2011-2013. PAP treatment was defined as presence of ≥1 durable medical equipment (HCPCS) code for PAP supplies. PAP adherence was defined as ≥2 HCPCS codes for PAP equipment, separated by≥1 month. Logistic regression models, adjusted for demographic and health characteristics, were used to estimate associations between PAP treatment or adherence and new AD, DNOS, and MCI diagnoses.

RESULTS

In this sample of Medicare beneficiaries with OSA, 59% were men, 90% were non-Hispanic whites and 62% were younger than 75y. The majority (78%) of beneficiaries with OSA were prescribed PAP (treated), and 74% showed evidence of adherent PAP use. In adjusted models, PAP treatment was associated with lower odds of incident diagnoses of AD and DNOS (OR=0.78, 95% CI:0.69-0.89; and OR=0.69, 95% CI:0.55-0.85). Lower odds of MCI, approaching statistical significance, were also observed among PAP users (OR=0.82, 95% CI:0.66-1.02). PAP adherence was associated with lower odds of incident diagnoses of AD (OR=0.65, 95% CI:0.56-0.76).

CONCLUSIONS

PAP treatment and adherence are independently associated with lower odds of incident AD diagnoses in older adults. Results suggest that treatment of OSA may reduce risk of subsequent dementia.

Maternal risk of hypertension 7-15 years after pregnancy: clues from the placenta

OBJECTIVE

To assess whether pre-eclampsia (PE)-related placental/extraplacental membrane findings are linked to moderately elevated blood pressure (BP) in pregnancy and later-life hypertension.

DESIGN

Prospective cohort.

SETTING

52 prenatal clinics, 5 Michigan communities.

SAMPLE

The POUCH Study recruited women at 16-27 weeks' gestation (1998-2004) and studied a sub-cohort in depth. This sample (n = 490) includes sub-cohort women with detailed placental assessments and cardiovascular health evaluations 7-15 years later in the POUCHmoms follow-up study.

METHODS

PE-related placental/extraplacental membrane findings (i.e. mural hyperplasia, unaltered/abnormal vessels or atherosis in decidua; infarcts) were evaluated in relation to pregnancy BP and odds of Stage 2 hypertension at follow up using weighted polytomous regression. Follow-up hypertension odds also were compared in three pregnancy BP groups: normotensives (referent) and moderately elevated BP with or without PE-related placental/extraplacental membrane findings.

MAIN OUTCOME MEASURES

Stage 2 hypertension (SBP ≥140 mmHg and/or DBP ≥90 mmHg, or using antihypertensive medications) at follow up.

RESULTS

After excluding women with pregnancy hypertension (i.e. chronic, PE, gestational), mural hyperplasia and unaltered/abnormal decidual vessels were each associated with Stage 2 hypertension at follow up: adjusted odds ratio (aOR) = 2.7, 95% CI 1.1-6.6, and aOR = 1.7 (95% CI 0.8-3.4), respectively. Women with moderately elevated BP in pregnancy and evidence of mural hyperplasia or unaltered/abnormal decidual vessels had greater odds of Stage 2 hypertension at follow up: aOR = 4.5 (95% CI 1.6-12.5 and aOR = 2.6, 95% CI 1.1-5.9, respectively.

CONCLUSIONS

PE-related placental/extraplacental membrane findings help risk-stratify women with moderately elevated BP in pregnancy for later development of hypertension.

TWEETABLE ABSTRACT

Placental findings associated with mother's risk of later-life hypertension.

Associations of plasma hypocretin-1 with metabolic and reproductive health: Two systematic reviews of clinical studies

The hypocretin system consists of two peptides hypocretin-1 and hypocretin-2 (HCRT1 and HCRT2). Hypocretin-containing neurons are located in the posterior and lateral hypothalamus, and have widespread projections throughout the brain and spinal cord. In addition to its presence in the cerebrospinal fluid (CSF), peripheral HCRT1 has been detected in plasma. Robust experimental evidence demonstrates functions of hypothalamic-originated HCRT1 in regulation of multiple biological systems related to sleep-wake states, energy homeostasis and endocrine function. In contrast, HCRT1 studies with human participants are limited by the necessarily invasive assessment of CSF HCRT1 to patients with underlying morbidity. Regulation by HCRT1 of energy homeostasis and reproduction in animals suggests similar regulation in humans and prompts these two systematic reviews. These reviews translate prior experimental findings from animal studies to humans and examine associations between HCRT1 and: 1) metabolic risk factors; 2) reproductive function in men, women and children. A total of 21 studies and six studies met the inclusion criteria for the two searches, respectively. Research question, study design, study population, assessments of HCRT1, reproductive, cardiometabolic data and main findings were extracted. Associations between HCRT1, metabolic and reproductive function are inconsistent. Limitations of studies and future research directions are outlined.

0837 Well-Being Predicts Sleep Disturbance in a Prospective Cohort of Older Adults

Introduction

Lower well-being negatively impacts health among older adults. Optimal sleep - a determinant of health - has been associated with higher well-being. Several domains of well-being, e.g., mindfulness and purpose in life have been shown to improve sleep. But, whether well-being impacts sleep remains unclear. This study examined associations between well-being and sleep duration, sleep quality, and incident insomnia symptoms among a nationally representative sample of older US adults.

Methods

This study analyzed data from the 2011-2013 National Health and Aging Trends Study (NHATS), a longitudinal, annual survey of community-dwelling Medicare beneficiaries. The exposure, a validated scale of well-being used questions on purpose, emotion, and self-satisfaction and divided responses into quartiles. Sleep outcomes included sleep duration, sleep quality, and insomnia symptoms. Unadjusted and adjusted linear and logistic regression models examined relationships between the health characteristics and well-being score in 2012 and sleep outcomes in 2013. Covariates included demographics and health characteristics.

Results

Half of study participants (n=2,000) were women. The mean sleep duration was 7.2 and 7.3 (standard error(SE) ±0.1) for men and women. Poor sleep quality was reported by 30% of subjects and more frequently among Hispanic subjects, older adults, and those with less education. The mean well-being score was 17.2 (SE ±0.07). Higher well-being scores correlated with male gender, younger age, higher education, marriage, and increased physical activity. Well-being scores in the 2nd - 4th quartile had lower odds of poor sleep quality (4th quartile adjusted odd ratio 0.24 (95% CI 0.15, 0.38). The highest well-being quartile had a 4-fold lower incidence of insomnia symptoms. Well-being scores were not associated with sleep duration

Conclusion

Higher well-being may protect older adults against the development of insomnia and poor sleep quality. Strategies to improve well-being could offer an innovative way to improve the health of older Americans though better sleep.

Support

none

1131 Obstructive Sleep Apnea Treatment and Dementia Risk in Older Adults

Introduction

Obstructive Sleep Apnea (OSA) has been linked to dementia and Alzheimer’s Disease (AD), as well as pre-dementia. The potential benefits of OSA treatment on cognitive performance are inconclusive. Further, the impact of OSA treatment on the development of neurodegenerative disorders has not been sufficiently studied. This study examined associations between Positive Airway Pressure (PAP) therapy and incident diagnosis of pre-dementia (MCI), dementia (DNOS), or AD in a population-level sample of older adults.

Methods

Using a random 5% sample from Medicare claims data (persons age 65 and older), individuals with an ICD-9 diagnosis code for OSA prior to 2011 (n=53,321) were selected for analyses. Over the survey period (2011-2013), we further identified persons newly diagnosed with MCI (n=443), DNOS (n=378), or AD (n=1,057). We also identified individual HCPCS claims for PAP equipment as evidence of prescription, and repeated HCPCS claims for supplies as evidence of adherence to PAP treatment. Logistic regression models were used to adjust for potential confounders including age, gender, hypertension, and Parkinson’s Disease that might increase risk for dementia.

Results

Seventy-eight percent of beneficiaries with OSA were prescribed PAP, and 74% showed evidence of adherent use. After adjustment for potential confounders, prescription of PAP was associated with significantly lower odds of incident AD and DNOS (OR=0.78, 95% CI: 0.69, 0.89; and OR=0.69, 95% CI: 0.55, 0.85). Lower odds of MCI, approaching statistical significance, were also observed among beneficiaries who were prescribed PAP (OR=0.82, (95% CI: 0.66, 1.02). Evidence of adherence to PAP was significantly associated with lower odds of incident AD (OR=0.65, 95% CI: 0.56, 0.76).

Conclusion

Among older individuals with OSA, PAP prescription and adherence are each associated with a significantly lower risk of incident AD or DNOS, though not MCI. Although a prospective cohort design cannot prove causality, results suggest that treatment of OSA could reduce risk of subsequent dementia.

Support

This study was supported by The American Academy of Sleep Medicine Foundation Strategic Research Award 115-SR-15 (PI Braley).

0654 Obstructive Sleep Apnea in Older Adults: Geographic Variation in CPAP Treatment

Introduction

Obstructive sleep apnea (OSA) is prevalent and consequential among older adults. Positive airway pressure (PAP) is likely to reduce associated morbidity, but adherence is inconsistent. Regional treatment variations that may reflect addressable differences in care are not sufficiently studied. We examined geographic variations in PAP treatment among older US adults.

Methods

A representative 5% sample of all Medicare beneficiaries, age 65+, enrolled in fee-for-service program in 2013 was analyzed. OSA diagnosis was defined by ICD-9 codes. PAP treatment was identified by HCPCS codes. Treatment adherence was defined as ≥2 HCPCS claims for PAP supplies on separate months. We examined state-specific proportions of Medicare beneficiaries with OSA who obtained PAP and showed adherence. Maps were created to represent state-specific proportions of beneficiaries who were treated and adherent, by quantiles. To examine more granular regional variations, we created maps representing hospital referral region (HRR)-specific proportions of treated among diagnosed, and adherent among treated. Scatterplots were used to identify the relationship between proportions of PAP treatment and adherence, by state.

Results

For the state-level data, PAP treatment and adherence rates were between 54%-87% and 59%-81%, respectively. Midwest states had higher CPAP treatment proportions (&gt;80%), while Northeast, Southwest and Southern states had CPAP treatment rates &lt;73%. State-level CPAP adherence showed similar patterns, with lowest rates in southern states and California (&lt;70%). Within-state variability of treatment patterns were observed, especially along the east and the west coasts. A scatterplot revealed that state-level CPAP treatment and adherence rates were linearly correlated, with Washington D.C., NY and NJ ranked lowest. In contrast, MT, ND and VT had the highest treatment and adherence rates.

Conclusion

These data show substantial state-level and regional variability of CPAP treatment and adherence among Medicare beneficiaries. Some geographic areas may merit prioritization in efforts to improve OSA treatment and adherence.

Support

This study was supported by The American Sleep Medicine Foundation Strategic Research Award 115-SR-15

0723 Associations Between Opioids, Non-Opioids and Central Sleep Apnea: A Case-Control Study

Introduction

Opioids are known to contribute to central sleep apnea (CSA), as they depress responsiveness to carbon dioxide and hypoxia. However, the role of non-opioid medications (antihistamines, myorelaxants, neuroleptics, antidepressants, and hypnotics) in CSA remains unclear. Given the hypothesized impact of non-opioids on the central nervous system, we examined associations between opioid and non-opioid medications and CSA.

Methods

Among all adults who underwent polysomnography testing at the University of Michigan’s Sleep Center between 2013-2018 (n=10,479), we identified 105 cases of CSA. Of these patients, we randomly selected 300 controls. Demographic and health characteristics, use of medications were obtained from medical charts. We classified study participants into three categories based on medication use: non-opioids only, opioids alone or in combination with non-opioids, and none. CSA was defined as a binary outcome using polysomnographic criteria as per the International Classification of Sleep Disorders-Third Edition. We used logistic regression to examine associations between medication use and CSA.

Results

Among participants, male:female ratio was 1:1 with a mean age of 49 (±14.3 SD) years. Opioid use alone was rare (4%), but more common in combination with non-opioids (17%), while the exclusive use of non-opioids was found among 38%.

In adjusted analyses for age and sex, those who used non-opioid alone were less likely to have a CSA diagnosis (OR=0.88, (95% CI 0.5-1.6); however, the use of opioids (alone or in combination with non-opioids) was associated with a 4-fold higher odds of CSA.

Conclusion

These data suggest that non-opioids have a protective influence on CSA. Conversely, opioids, alone, or in combination with non-opioids, were associated with increased CSA risk, that may be attributed to opioids alone, or to opioids and non-opioids interactions. However, as opioids were mostly co-prescribed with non-opioids, the sole effect of opioids from the synergistic effect with non-opioids are difficult to disentangle.

Support

Dr. Gavidia was supported by a T32 Post-Doctoral Fellowship in Neuroscience NIH/NINDS T32 NS 007222

0221 Late Meals, Sleep Duration, and Sleep Fragmentation: Findings From the American Time Use Survey

Introduction

Sleep hygiene recommendations discourage eating close to bedtime, though published data on the impact are not consistent. Associations between eating or drinking, within 1-hour prior to bedtime, sleep duration and sleep fragmentation were examined in a nationally-representative sample.

Methods

Data from the American Time Use Survey (ATUS), administered to a nationally representative sample of n=201,151 US residents aged ≥15 years were utilized. In an annual phone interview, ATUS participants were asked to record their activities during a 24-hour period (04:00am to 04:00am on the interview day) and were randomly selected to report weekdays or weekend activities. The present analysis included data from 2003–2018 and restricted to weekday respondents (n=124,242). Reporting of eating/drinking activities within 1-hour prior to bedtime was considered as a dichotomous variable (yes/no). Sleep fragmentation was defined as any awakening during the primary sleep episode (yes/no). Linear and logistic regression models, adjusted for age, sex, cohabitation, education and employment, were used to examine associations between eating/drinking and sleep duration or sleep fragmentation.

Results

In this ATUS sample, 56% of respondents were female and the mean age was 45 years. Mean sleep duration was 8.02 (0.007) hours, and 6% of survey participants ate/drank within 1-hour prior to bedtime. Overall, eating/drinking within 1-hour prior to bedtime was associated with longer sleep duration (p&lt;0.01). Women and men who ate/drank within 1-hour prior to bedtime, in comparison to those who did not, had 35 minutes and 26 minutes longer sleep duration (p- value&lt;0.0001) Eating/drinking activities within 1-hour prior to bedtime were associated with 1.8 higher odds of fragmented sleep (p&lt;0.001).

Conclusion

In this large population-based survey, weekday eating or drinking within 1-hour prior to bedtime was associated with sleep fragmentation and longer sleep duration. Causal pathways would be difficult to discern, though sleep fragmentation could lead to compensatory increases in sleep duration.

Support

None

0631 Respiratory Infection Risk in PAP Users

Introduction

Although positive airway pressure (PAP) effectively treats obstructive sleep apnea (OSA), adherence remains suboptimal for many patients. One factor that may influence a patient’s decision to use PAP is a prevailing concern that use of unsanitized PAP equipment may serve as a reservoir for pathogens that cause respiratory tract infections (RTI). Conversely, untreated OSA could also have long-term consequences, including impaired immune function, raising the possibility that PAP therapy could reduce RTI risk. The objective of this study is to compare RTI patterns before and after initiation of PAP in persons with OSA, and examine clinical characteristics that may influence RTI risk.

Methods

Patients with at least 2 years of continuous primary care at Michigan Medicine preceding and following their OSA diagnosis (N=480) were considered eligible for analyses. Medical charts were reviewed to determine pre- and post-PAP RTI frequency and characteristics during this time frame. Change in RTI frequency was examined with paired T-tests.

Results

Male:female ratio was 1:1, mean age 56 years, mean apnea hypopnea index was 10, N=85/480 had documented good PAP compliance (defined as ≥ 4h/night, 70% of the nights). Among 480 patients, total RTI frequency pre and post PAP therapy were 170 and 144 respectively (p=0.11). Data collection is ongoing.

Conclusion

These preliminary data suggest that use of PAP is not associated with increased risk of respiratory infections. Further data regarding clinical characteristics that may influence RTI risk in OSA patients will be informed by ongoing data collection and planned multivariable analyses.

Support

Dr. Gavidia is supported by a Training in Clinical and Basic Neuroscience T32 (NIH/NINDS T32 NS 007222)

The influences of sleep duration, chronotype, and nightwork on the ovarian cycle

Despite research indicating that sleep disorders influence reproductive health, the effects of sleep on reproductive hormone concentrations are poorly characterized. We prospectively followed 259 regularly menstruating women across one to two menstrual cycles (the BioCycle Study, 2005-2007), measuring fasting serum hormone concentrations up to eight times per cycle. Women provided information about daily sleep in diaries and chronotype and night/shift work on a baseline questionnaire. We evaluated percent differences in mean hormone concentrations, the magnitude of shifts in the timing and amplitude of hormone peaks, and the risk for sporadic anovulation associated with self-reported sleep patterns and night/shift work. We estimated chronotype scores - categorizing women below and above the interquartile range (IQR) as "morning" and "evening" chronotypes, respectively. For every hour increase in daily sleep duration, mean estradiol concentrations increased by 3.9% (95% confidence interval [CI] 2.0, 5.9%) and luteal phase progesterone by 9.4% (CI 4.0, 15.2%). Receiving less than 7 hours of sleep per day was associated with slightly earlier rises in peak levels for several hormones. Women reporting night/shift work (n = 77) had lower testosterone relative to women employed without night/shift work (percent difference: -9.9%, CI -18.4, -0.4%). Women with morning chronotypes (n = 47) had earlier rises in estradiol during their cycles and potentially an earlier rise in luteinizing hormone. Compared to those who had intermediate chronotypes, women with evening chronotypes (n = 42) had a later luteinizing hormone peak of borderline statistical significance. A reduced risk for sporadic anovulation was suggested, but imprecise, for increasing hours of daily sleep leading up to ovulation (risk ratio 0.79, CI 0.59, 1.06), while an imprecise increased risk was observed for women with morning chronotypes (risk ratio 2.50, CI 0.93, 6.77). Sleep-related hormonal changes may not greatly alter ovarian function in healthy women, but have the potential to influence gynecologic health.