Fetotoxicity of angiotensin-converting enzyme inhibition in primate pregnancy: a prospective, placebo-controlled study in baboons (Papio hamadryas).
OBJECTIVE
Serious concerns have been raised about angiotensin-converting enzyme inhibition in pregnancy. The central question remains: does toxicity of angiotensin-converting enzyme inhibition pertain to pregnant humans?


METHODS
A prospective, placebo-controlled study was performed to investigate the effect of angiotensin-converting enzyme inhibition on pregnancy outcome in the baboon. Subjects (N = 12) received active and placebo treatments sequentially in a crossover protocol. Data were analyzed with two-sample t tests, analysis of variance, Fisher's exact test, or Kaplan-Meier survival analysis, where appropriate.


RESULTS
Chronic administration of enalapril (7.5 mg per day) from before conception achieved moderate but sustained angiotensin-converting enzyme inhibition as determined by repeated measures of renin-angiotensin system parameters (serum angiotensin-converting enzyme activity, plasma renin activity and plasma angiotensin I, angiotensin II, and aldosterone concentrations). Serum angiotensin-converting enzyme activity was significantly reduced throughout (< 10 nmol.ml-1.min-1, p < 0.01), with significant increases in plasma renin activity and angiotensin I (p < 0.01). Angiotensin II and aldosterone were maintained unchanged compared with placebo. There was a significant incidence of fetal death or intrauterine growth retardation in fetuses exposed to enalapril (eight of 13, zero on placebo, p < 0.01). When the definition of adverse pregnancy outcome was restricted to fetal death alone (four of 13) the difference remained significant (p < 0.05). Maternal arterial pressure was unchanged before conception, but a small and significant fall (10 to 15 mm Hg, p < 0.01) was detected throughout pregnancy. There was no fetal malformations.


CONCLUSIONS
The study provides definitive evidence for serious consequences of angiotensin-converting enzyme inhibition in pregnancy of high-order primates.
Harewood
W J
WJ
Department of Renal Medicine, Royal Prince Alfred Hospital, Camperdown, Sydney, New South Wales, Australia.
Phippard
A F
AF
Duggin
G G
GG
Horvath
J S
JS
Tiller
D J
DJ
D000450:Aldosterone / Q000097:blood; D000704:Analysis of Variance; D000803:Angiotensin I / Q000097:blood; D000804:Angiotensin II / Q000097:blood; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004656:Enalapril / Q000633:toxicity*; D005260:Female; D005313:Fetal Death / Q000139:chemically induced*; D005317:Fetal Growth Retardation / Q000139:chemically induced*; D010215:Papio; D007703:Peptidyl-Dipeptidase A / Q000097:blood*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D011897:Random Allocation; D012083:Renin / Q000097:blood
D000804:Angiotensin II; D000450:Aldosterone; D004656:Enalapril; D000803:Angiotensin I; D007703:Peptidyl-Dipeptidase A; D012083:Renin