HOME >> BIOLOGY >> NEWS
Embryos that implant in uterus 'late' prove more likely to die in first weeks of pregnancy

Researchers at the National Institute of Environmental Health Sciences said today that fertilized human eggs that implant late are less likely to survive.

The road to birth is a perilous one. These same NIEHS scientists showed in 1988 (New England Journal of Medicine, 319, pp 189-94) that 25 percent of fertilized eggs fail to survive six weeks -- so early that most mothers did not know they had been pregnant. Only daily urine testing for shifting traces of a hormone called hCG confirmed these pregnancies and their loss. The 25 percent early loss, when added to the clinical miscarriages that occur later, means that at least one-third of all embryos fail.

Today, the researchers reported they have found that the lost fetuses tend to be those that implant late. (NEJM, June 10.) The implantation of the fertilized egg in the wall of the uterus is necessary for the nourishment and growth of the fetus. Surviving pregnancies implanted only about one day earlier, on average, than the non-survivors: 10.5 days v. 9.1 days from fertilization to implantation. But the day-by-day trend was clear. If a fertilized egg implanted by the ninth day, it had only a 13 percent chance of loss. The risk rose to 26 percent if the implantation was on the tenth day, 52 percent on the eleventh day, and 82 percent thereafter. All three implantations after day 12 ended in early loss. There was no association in the NIEHS study between late implantation and the clinical miscarriages that occurred later in pregnancy.

NIEHS' Allen J. Wilcox, M.D., Ph.D., Donna Baird, Ph.D., and Clarice R. Weinberg, Ph.D., said their study could not determine the mechanisms at work. They speculate that embryos that implant more slowly may be imperfect in some way. Thus, they said, "the uterus may be receptive to pregnancy only during a limited time-window, shutting out defective embryos that get there too late. This would spare a mother the physiologic burden of supp
'"/>

Contact: Bill Grigg
grigg@niehs.nih.gov
301-402-3378
NIH/National Institute of Environmental Health Sciences
10-Jun-1999


Page: 1 2

Related biology news :

1. First Dinosaur Embryo Skin Discovered -- Unhatched Embryos Are First Ever Found Of Giant-Plant Eating Dinosaurs
2. Who Needs Flowers? Transgenic Plants Sprout Embryos On Leaves
3. At Lifes Most Sensitive Stage, Embryos Cope With Stress
4. University of Pittsburgh medical center among first to implant heart assist device
5. Medical implants work better when you rough them up, study finds
6. DCI donor services begins distribution of tissue implants
7. Researchers model embryo implantation and tumour metastasis in fruit flies
8. Injectable tissue implant could repair ravages of breast cancer surgery
9. Improving bone implant technology
10. Researchers envision intelligent implants
11. Rutgers researchers test polymer reliability for medical implants

Post Your Comments:
*Name:
*Comment:
*Email:


(Date:12/20/2016)... , Dec. 20, 2016 The rising ... rental and leasing is stoking significant interest in ... frequency technology, Bluetooth low energy (BLE), biometrics and ... the next wave of wireless technologies in the ... system to advanced access systems opens the market ...
(Date:12/16/2016)... 2016   IdentyTechSolutions America LLC , a ... solutions and a cutting-edge manufacturer of software and ... offering seamless, integrated solutions that comprise IDT biometric ... solutions provide IdentyTech,s customers with combined physical identification ... crime and theft. "We are proud ...
(Date:12/15/2016)... Germany , December 15, 2016 ... announced an agreement with NuData Security, an award-winning ... partnership will enable clients to focus on good customer experience, ... protection regulation. ... In order to provide a one-stop fraud prevention suite, ...
Breaking Biology News(10 mins):
(Date:1/19/2017)... , ... January 19, 2017 ... ... advanced software solutions for pharmaceutical research and development (R&D), today announced the ... omic data analysis and interpretation for the rapidly evolving field of precision ...
(Date:1/19/2017)... ... January 18, 2017 , ... The American Medical Informatics Association ... Data Sharing Policy. Specifically, the nation’s leading informatics experts, said data sharing plans ... policy. AMIA recommended that NIH earmark funding for researchers to produce and execute ...
(Date:1/19/2017)... Md. , Jan. 18, 2017  Northwest Biotherapeutics, ... developing DCVax® personalized immune therapies for operable and inoperable ... Bosch , Chief Technical Officer of NW Bio, will ... January 19, 2017, at the Hyatt Regency Hotel in ... Bosch will chair the session entitled "New Therapeutic Approaches ...
(Date:1/18/2017)... --  Boston Biomedical , an industry leader in the ... pathways, will feature data from two clinical studies for ... Gastrointestinal Cancers Symposium, held from January 19-21, in ... is an orally-administered investigational agent designed to inhibit cancer ... cells (CSCs) possess the property of stemness – the ...
Breaking Biology Technology:
Cached News: