Does gender make a difference in sleep patterns?


A study looks at whether women are at greater risk of sleep problems than their male counterparts. Also, are cesarean deliveries increasing the risk of childhood obesity? Plus: A study highlights the need for further research in postpartum psychosis.

A comparison of sleep patterns in men and women, published in the Proceedings of the National  Academy of Sciences, shows that gender makes a difference when it comes to likelihood of having sleep and wake disturbances. The study, while small, may be the first to look at sex differences in sleep and waking under highly controlled conditions with simultaneous control for menstrual cycle phase and hormonal contraceptive use.

US and Canadian researchers looked at sex differences in diurnal and circadian variation of sleep and waking while carefully controlling for menstrual cycle phase and hormonal contraceptive use. The diurnal and circadian variation of sleep and alertness of 8 women during 2 phases of the menstrual cycle and 3 women studied during the midfollicular phase were compared with that of 15 men. The participants underwent an ultradian sleep-wake cycle (USW) procedure that consisted of 36 cycles of 60-minute wake episodes alternating with 60-minute nap opportunities. During the wake episodes and naps, core body temperature (CBT), salivary melatonin, subjective alertness, and polysomnographically recorded sleep were measured.

Women had a significant phase advance of CBT but not melatonin rhythms and an advance in diurnal and circadian variation of sleep measures and subjective alertness. Compared with men, they also had increased amplitude of diurnal and circadian variation of alertness, mainly due to a larger decline in nocturnal nadir.

Women had significantly shorter stage 1 and non-rapid-eye-movement (REM) sleep during the nocturnal sleep time. (REM is the fifth of five stages of sleep, through which individuals proceed in order and in cycles throughout the night.) REM sleep also was significantly longer for women than for men. Women and men did not differ in habitual bed and wake times, sleep efficiency (overall sense of how an a participant slept), sleep onset latency (time to fall asleep), REM sleep onset latency (time to reach the REM stage of sleep), stage 2 sleep (the second stage of the sleep cycle), or slow-wave sleep (deep sleep, the third stage of sleep). Women who took hormonal contraceptives had increased melatonin secretion but their circadian timing was no different than that for naturally cycling women in both the follicular and luteal phases.

The findings, the authors said, indicate that women’s rhythms of CBT, sleep and subjective alertness are advanced during the midfollicular and midluteal phases, which may explain why women are more susceptible to sleep and wake disturbances than are men. 

NEXT: Do cesarean deliveries increase the risk of childhood obesity?


Does cesarean delivery increase risk of childhood obesity?

Results of a prospective cohort study published in JAMA Pediatrics suggest that cesarean delivery has a negative impact on weight in childhood.

The Growing Up Today Study included 22,068 children born to 15,271 women who were followed via questionnaires from ages 9 to 14 years through ages 20 to 28 years. Data analysis was done from October 2015 to June 2016. Risk of obesity was based on International Obesity Task Force or World Health Organization body mass index (BMI) cutoffs. Secondary outcomes included risks of obesity associated with changes in the mode of delivery and differences in risk between siblings who had discordant delivery modes.

Of the 22,068 children examined, 4921 (22.3%) were born via cesarean delivery. Through the end of follow-up, the cumulative risk of obesity was 13% among all participants. The adjusted risk ratio for obesity among those born via cesarean versus those delivered vaginally was 1.15 (95% confidence interval [CI], 1.06-1.26; P = .002). The association was strongest in women who had no known indications for cesarean delivery (adjusted risk ratio [RR], 1.30; 95% CI, 1.09-1.54; P = .004). Children born vaginally to women with a previous cesarean had a 31% lower risk (95% CI, 17%-47%) of obesity when compared to children who were born to mothers who had a history of repeated cesarean deliveries. Individuals who were born via cesarean had 64% higher odds (95% CI, 8%-148%) of obesity than their siblings who had been born vaginally.

The investigators concluded that cesarean birth was associated with obesity in children after accounting for major confounding factors, including BMI. Adjustment for maternal prepregnancy BMI did result in the most attenuation of the association but it still remained significant. When maternal BMI was treated as a continuous variable, the RR for obesity in offspring was 1.13 (1.03-1.23; P<0.001)

The researchers urged further research into the impact of cesarean delivery on childhood obesity, but still believe that, absent a clear indication for the procedure, doctors and patients should weigh the risk when determining whether to go forward with a cesarean.

NEXT: Is more research needed on postpartum psychosis?


More research needed on postpartum psychosis

A review of existing literature on postpartum psychosis by investigators from Northwestern University suggests that women with bipolar disorder may be at significantly higher risk of the condition and that more research is needed in this area.

Published in the American Journal of Psychiatry, the findings reflect an analysis of epidemiologic and genetic research and physiologic postpartum triggers (circadian, endocrine, immunologic) of psychosis. The authors summarized systematic reviews and used the clinical studies to provide strategies for prevention, treatment options, and diagnostic recommendations.

In population-based register studies of psychiatric admissions, incidence of first-lifetime onset postpartum psychosis was found to vary from 0.25 to 0.6 per 1000 births. Following an incipient episode, 20% to 50% of women had isolated postpartum psychosis. The other women had episodes outside the perinatal period, typically within the bipolar spectrum.

The investigators found that fewer than 30 publications have focused on treatment of postpartum psychosis. The largest of the studies (n = 64) found evidence that lithium showed great efficacy when used for acute and maintenance treatment and, in another report, electroconvulsive therapy was shown to be of benefit, while inpatient care is typically required to complete the diagnostic evaluation and initiate treatment. The risk of relapse after a subsequent pregnancy was 31% for women who had isolated postpartum psychoses (95% confidence interval = 22 – 42).

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