Pregnancy advances the daily schedule

Add this to the list of things to expect: Get up early, at least during the first quarter.

A new study from Washington University in St. Louis found that women and mice altered their daily schedule earlier by a few hours during the first third of their pregnancy. A new study by researchers from the arts and sciences and medical school shows how impending motherhood induces changes in the mothers' daily schedule that, when interrupted, can endanger pregnancy, as indicated in the report. Journal of biological rhythms.

"This is a very important first step in understanding what happens during term pregnancy, and it could possibly inform our ability to intervene and prevent premature birth in some populations," said Carmel A. Martin-Fairey , postdoctoral fellow at the department. Biology in Arts and Sciences and Obstetrics and Gynecology in the Faculty of Medicine.

Nationally, one in 10 babies is born too early, before 37 weeks of pregnancy are over. Shift work and other disturbances of a regular sleep-wake schedule have been badociated with prematurity and other reproductive problems. But previously, little was known about the circadian calendar during pregnancy.

Surveillance before and during pregnancy

Almost every organism has a biological clock that holds the daily hour, resulting in 24-hour behavior and physiology rhythms. These rhythms involve cycles of sleep and waking, metabolism, hormone secretion, level of activity and other physical processes – and can affect the reproduction of many species, including l & # 39; man.

The new study followed 39 women from the Saint-Louis region as part of a larger, ongoing study of 1,000 births. The participants in the study wore wristwatches constantly monitoring their daily activities and resting for two full weeks before attempting to conceive. Once the women discovered that they were pregnant, they again wore the watches for the duration of their pregnancy until delivery.

In mice, the experimental setup was very similar, with researchers monitoring activity before and during pregnancy, in part by observing the time that mice spent on a running wheel.

The study found that mice and women altered their daily schedule earlier by a few hours during the first third of their pregnancy.

In mice, this breakthrough in the daily activity pattern of rest was detectable as early as the third day of pregnancy and persisted until 10 days before delivery. Similarly, the progress of the daily schedule of pregnant women has gradually returned to normal before delivery.

"For mice at least, the fact that their activity advanced so early in pregnancy was surprising, we had no idea," said Sarah England, professor of obstetrics and gynecology Alan A. and Edith L. Wolff. England is the Assistant Program Director of the March of Dimes Premature Research Center at the School of Medicine and co-author of the new study.

"What happens in early pregnancy is that they postpone their total activity earlier in the day," said Erik Herzog, professor of biology at Arts and Sciences and lead author of the new study. . "But they do not seem to sleep more or be more active at the beginning of their pregnancy, it's just a change in their daily rhythm."

"Later in the pregnancy, it is at that point that we begin to see that they are carrying a load and that they are running less," said Herzog of the mice participating in the event. ;study. "So, they seem to be separable processes."

Certainly, an exhausting workload can cause a mother of childbearing age to change her schedule and her rest and sleep patterns. But Herzog said that this study shows that it's more than that, because of the jet lag of the pregnancy.

"There may be some fatigue, or extra work needed to carry a baby, but there is something in the daily timing system that changes in early pregnancy probably because of hormones badociated with pregnancy," did he declare.

The researchers also found that total activity during pregnancy was significantly reduced in both mice and women.

"In mice, it was centered on the end of gestation, while in women, it was significantly reduced throughout pregnancy," said Martin-Fairey.

A first step towards understanding circadian rhythms during pregnancy

Thus, the new research results provide insights into potential medical problems as they indicate that pregnancy induces changes in daily rhythms, altering both the onset and activity level.

"This discovery is fascinating because, although we know that miscarriage, preterm birth and other serious complications during pregnancy are related to disturbances of the circadian rhythm of the mother, we do not know how it works," said Kelle H Moley, Chief Medical Officer for March of Dimes in a statement. "This study allows us to better understand how a normal circadian rhythm promotes a healthy pregnancy."

This is the first publication published by these collaborators on circadian rhythms using data from this large study on St. Louis. Other future work will help researchers better understand the impact of shift work and other high-risk groups of premature delivery.

"In premature births, there is a disparity in health, with African-American women having a higher rate," said England. "We are well located in St. Louis to deepen some of the mechanisms underlying this disparity."

"Sleep in medicine is little studied," said Emily S. Jungheim, MD, an badociate professor in the department of obstetrics and gynecology of the faculty of medicine and co-author of the new study. "Even in healthy women and men – those who eat well, who do physical exercise – the only thing they are willing to do without hesitation, is to skimp on Many people do not care about its importance. "

But sleep is something that can always be improved. Women seeking to conceive can prioritize sleep.

"Often, if you look during pregnancy, the cat is already out of his bag," Jungheim said. "You can not do anything to remedy the situation because everything is already gone, but if you can identify a risk factor of premature delivery in a woman of childbearing age before she is pregnant, you have time to change it and see if you have solved the problem – before she gets pregnant. "