Placental Transfer of Zidovudine in First Trimester of Pregnancy
Zidovudine (Retrovir; AZT)
was the first and is still one of the most frequently employed
antiretroviral drugs used to prevent mother-to-child
(vertical) transmission of HIV. It is not generally
recommended for use in the first trimester of pregnancy
because of reservations about its potential teratogenicity (toxicity
to the fetus) during the organogenesis phase.
The
aim of the current study was to investigate the placental transfer
of zidovudine in the first trimester
of human pregnancy.
Twenty-six
pregnant women were given 2 oral doses of zidovudine
(200 mg) before first trimester surgical termination of pregnancy.
Maternal blood, fetal tissue, and coelomic
and amniotic fluid were collected for drug analysis.
Results
Zidovudine was detected in all samples of maternal serum and fetal
tissue but present in only 7 samples of amniotic and coelomic
fluid.
Zidovudine concentration in fetal tissue was similar to that of
maternal serum.
The median fetal/maternal
ratio was 0.92 and was not associated with gestational age (r
= 0.03, P = .89).
The
authors conclude, “Zidovudine crossed the first trimester human placenta readily
and achieved the level of maternal serum rapidly. Patients who
choose to take zidovudine in first trimester
of pregnancy should be counseled about the potential fetal effects.”
Department of Obstetrics and Gynecology, the Chinese
University of Hong Kong, Prince of Wales Hospital, Hong Kong;
and Department of Pharmacology, the Chinese University of Hong
Kong, Hong Kong.
10/17/05
Reference
S
S Siu and
others. Placental transfer of Zidovudine
in first trimester of pregnancy. Obstetrics
and Gynecology 106(4):
824-827. October 2005.
