Document Detail

The placental transfer of mifepristone (RU 486) during the second trimester and its influence upon maternal and fetal steroid concentrations.
MedLine Citation:
PMID:  2372525     Owner:  NLM     Status:  MEDLINE    
A double-blind, placebo-controlled study has assessed the maternal and fetal endocrine effects of the maternal administration of the anti-progestin mifepristone in mid-pregnancy. There were six women in each group. Four hours after oral administration of 600 mg mifepristone, the drug was detected in both maternal and fetal circulations and in the amniotic fluid. No significant changes in progesterone, cortisol, oestradiol, or aldosterone concentrations were detected in the maternal circulation after treatment with mifepristone or placebo. In women treated with mifepristone, the mean fetal aldosterone level was 1699 (SD 217) pmol/l which was significantly higher than the mean level of 999 (SD 84) pmol/l in the control group but no significant changes occurred in the fetal progesterone, oestradiol or cortisol concentrations. The significance of these results is discussed in relation to the possible therapeutic uses of mifepristone for inducing labour.
The effects of RU 486, a competitive progesterone receptor antagonist, on maternal and fetal steroid concentrations were investigated in a double-blind study of 12 women in the 16th-19th weeks of pregnancy. The 6 study subjects received 600 mg of oral RU 486 on the day of abortion induction, while 6 controls received a placebo tablet. RU 486 was detected in maternal and fetal circulations and amniotic fluid 4 hours after administration to the 6 subjects, indicating that RU 486 and its metabolite, RU 42,6333, rapidly cross the placenta. There were no significant differences between cases and controls in terms of maternal progesterone, cortisol, estradiol, or aldosterone concentrations. In addition, fetal progesterone, estradiol, and cortisol concentrations did not differ between the RU 486 and placebo groups; however, fetal aldosterone levels were significantly higher in the treatment group (mean, 1699 pmol/l) than in controls (mean, 999 pmol/l). It is not known whether this unexpected f inding reflects the action of RU 486 blocking fetal mineralocorticoid receptors or was attributable to chance. Although more research is needed on the fetal endocrine effects of mifepristone, it appears that RU 486 has substantial potential for inducing labor in 2nd trimester abortion without serious drug-related side effects.
N C Hill; M Selinger; J Ferguson; I Z MacKenzie
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  British journal of obstetrics and gynaecology     Volume:  97     ISSN:  0306-5456     ISO Abbreviation:  Br J Obstet Gynaecol     Publication Date:  1990 May 
Date Detail:
Created Date:  1990-08-27     Completed Date:  1990-08-27     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7503752     Medline TA:  Br J Obstet Gynaecol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  406-11     Citation Subset:  AIM; IM; J    
Nuffield Department of Obstetrics and Gynaecology, University of Oxford, John Radcliffe Hospital, Headington.
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MeSH Terms
Aldosterone / blood
Cortisone / blood
Double-Blind Method
Estradiol / blood
Fetal Blood / analysis*
Maternal-Fetal Exchange*
Mifepristone / administration & dosage,  metabolism*
Pregnancy Trimester, Second
Progesterone / blood
Random Allocation
Steroids / blood*
Reg. No./Substance:
0/Steroids; 50-28-2/Estradiol; 52-39-1/Aldosterone; 53-06-5/Cortisone; 57-83-0/Progesterone; 84371-65-3/Mifepristone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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