The biology of uterine fluid: How it informs the fetus of mom's world

June 22, 2017, Cell Press
This figure shows a normal uterine fluid environment during embryo preimplantation. Credit: Zhang, Ying et al., Trends in Molecular Medicine 2017

A developing fetus bathes in a mixture of cellular secretions and proteins unique to its mother's uterus. Before fertilization, the pH of uterine fluid helps create a conducive environment for sperm migration, and afterward, its volume supports the embryo as it implants onto the wall of the uterus. Recent evidence suggests that uterine fluid may play another key role in embryonic development: communicating the mother's outside conditions to the fetus, so that the latter can prepare accordingly. A review of this research appears on June 22 in Trends in Molecular Medicine.

Studies in livestock, rodents, and humans have shown that information from a mother's environment (e.g., food availability, stress, and pollutant exposure) can leave epigenetic tags on the DNA of her , potentially influencing the progression and long-term health of the developing embryo. Scientists have hypothesized that blood flow via the placenta might constitute one way the body communicates the mother's condition to the fetus, yet there is evidence that the fetus can react to changes such as those stemming from the mother's diet long before the establishment of the placenta.

"This suggests the involvement of uterine fluid as the communication medium to transfer information between the maternal environment and the floating embryo," says senior author En-Kui Duan, a reproductive biologist at the Institute of Zoology, Chinese Academy of Sciences. "The preimplantation period is a critical time for programming offspring health, and thus, expecting mothers should keep a good diet and good mood, and stay away from harmful chemicals during this critical window."

While there is much to be learned about how mother-fetus communication takes place, the theory is that information in extracellular vesicles (molecular packages that move from cell to cell) within uterine fluid and tissue deliver their cargo, including microRNAs and , to the fetus. These molecules may be tagging fetal cell DNA in ways that alter which genes are being expressed, and thus can contribute to "programming" how the embryo and/or placenta develop. Consequently, researchers are interested in learning which specific maternal environmental exposures and/or behaviors could change the composition of molecules transported via the uterine fluid to the fetus.

For example, mouse studies have shown that a low-protein maternal diet can reduce the level of certain amino acids in uterine fluid and affect gene expression of nutrition- transport-related genes. While these changes might prevent malnutrition in the developing embryo, once grown, the mouse offspring are more predisposed to heart disease when compared to animals on a regular diet.

Hongmei Wang, co-senior author of this paper, speculates that uterine fluid could someday be used to analyze or even manipulate what signals are being received by a fetus. "For now, uterine fluid collection is not a standard biomarker, yet many studies have revealed its potential role for non-invasive analysis, and we also see great potential in it," she says. "One, it can be screened by using ultrasound recording coupled with computational/biomechanical analysis; and two, uterine fluid can also be collected during an endometrial examination."

Explore further: Female diet alters the nutrient composition of fluid in the womb

More information: Trends in Molecular Medicine, Zhang, Ying et al.: "Uterine Fluid in Pregnancy: A Biological and Clinical Outlook." http://www.cell.com/trends/molecular-medicine/fulltext/S1471-4914(17)30080-1 , DOI: 10.1016/j.molmed.2017.05.002

Related Stories

Female diet alters the nutrient composition of fluid in the womb

February 19, 2015
Scientists at the University of Soutahmpton's Faculty of Medicine have discovered that maternal diet affects the nutrient composition of fluid in the womb of women and thus may aid in the development of nutritional interventions ...

Follistatin is a key player in embryo implantation

June 2, 2017
Looking to improve the success rate of assisted reproductive technologies, researchers at Baylor College of Medicine investigated in more detail the mechanism involved in successful embryo implantation, an essential component ...

Endometrial cancer driver mutations detectable in uterine lavage fluid

December 27, 2016
Mutations that have been linked to endometrial cancer can be found in the uterine lavage fluid of pre- and post-menopausal women both with and without detectable cancer, according to a study published in PLOS Medicine by ...

Mother's stress affects the baby through amniotic fluid

May 29, 2017
If the mother is stressed over a longer period of time during pregnancy, the concentration of stress hormones in amniotic fluid rises, as proven by an interdisciplinary team of researchers from the University of Zurich. Short-term ...

Study identifies molecular key to healthy pregnancy

July 17, 2014
Scientists have identified a crucial molecular key to healthy embryo implantation and pregnancy in a study that may offer new clues about the medical challenges of infertility/subfertility, abnormal placentation, and placenta ...

Scientists visualize embryo implantation in the mouse uterus in unprecedented 3-D detail

December 14, 2016
UC San Francisco researchers have visualized the earliest stages of pregnancy in unprecedented detail in laboratory animals and human tissue using new laboratory imaging techniques that promise to enable rapid progress in ...

Recommended for you

Undiagnosed STIs can increase negative PMS symptoms

September 17, 2018
Women that have undiagnosed sexually transmitted infections may be at greater risk of experiencing negative premenstrual symptoms (PMS), according to new Oxford University research.

High dose folic acid does not prevent pre-eclampsia in high risk women

September 13, 2018
Taking high dose folic acid supplements in later pregnancy (beyond the first trimester) does not prevent pre-eclampsia in women at high risk for this condition, finds a randomised controlled trial published by The BMJ today.

Study finds air purifiers may benefit fetal growth

September 12, 2018
A new study led by SFU health sciences researchers Prabjit Barn and Ryan Allen reveals fetal growth may improve if pregnant women use portable air purifiers inside their homes.

Delayed childbearing is a growing source of multiple births, study shows

September 12, 2018
Starting in the 1980s, the number of multiple births—twins, triplets, quadruplets and quintuplets—steadily increased from about 20 sets per 1,000 live births to almost 35 sets per 1,000 live births in the 2010s.

Transforming pregnancy research with a smartphone app

September 5, 2018
For years, pregnant women have been underrepresented in biomedical research. Current treatments, interventions and guidelines do a poor job of taking into consideration the diverse characteristics of all pregnant women.

For women undergoing IVF, is fresh or frozen embryo transfer best?

August 21, 2018
The world's first baby born via in-vitro fertilization turned 40 years old this summer. Still, after four decades, IVF is a relatively new field with ongoing debate on how to get the best results for families who have placed ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.