In
this publication were reported the results of the Assisted
Reproduction procedures performed in 1996, in which a total
of 10.359 cycles started and 2.503 liveborn (1.278 unique,
821 twins, 331 triplets and 73 quadruplets or more) were
included. The medium age of the treated women was 33. The
three countries that contributed with the higher number
of cases were Brazil (38.7%), Argentine (26.1%) and Mexico
(9.9%). From the total of the cycles started, 51.8% are
related to IVF, 44.1% to ICSI and 4.2% to GIFT. This distribution
points a substantial change in the application of new reproductive
technologies, as in 1993 ICSI represented only 0.2%, 6.1%
in 1994 and 32.7% in 1995. Between 1993 and 1995, the number
of centers in which reported ICSI procedures was 2, 10 and
27. In the present time, 41 centres belonging to 10 countries
reported procedures of micromanipulation, as ICSI, Assisted
Hatching and the combination of both. The clinical pregnancy
rates (TEC) and birth with one liveborn, by aspiration,
were 21.2% and 16.1% for IVF, 24.6% for ICSI and 36.4% and
28.9% for GIFT.
In IVF, due to tubal factors, the TEC and the chance of
pregnancy (RD) are significantly lower as the age of the
woman increases. The chance of pregnancy is 1.4 times higher
in women aged 30 – 34 in relation to those aged 35
– 39. At the same time, this age range has a chance
of 1.7 times higher to those women aged =40. In the male
factors, to the interior of each age category, the transference
of 1 or 2 embryos has a positive global effect in the TEC
and RD.
This relation loses statistical meaning with the transference
of 4 embryos or more. The implantation rate (number of gestational
sacs / number of embryos transferred) is significantly higher
in women aged < 35 in relation to those aged 35 – 39. At the same time, the implantation rate in this group
of age is also significantly higher than in the women aged
=40.
The multiple pregnancy rates were analyzed by the first
time, considering the number of embryos transferred and
the age of the woman. In women aged < 35, the multiple
pregnancy rate to transfer 3, 4 and 5 embryos is 23.5%,
33.2% and 43.3% respectively. Moreover, the extreme multiple
gestation (= 3 sacs) is 4.9%, 16.4% and 21.2% respectively.
In relation to the transference of cryopreserved embryos,
the global TEC is 18.2% and vary between 8% to transfer
2 embryos to 33.3% to transfer 5. The implantation rates
are lower to transfer thawed embryos in relation to the
fresh ones; however, the spontaneous miscarriage rates are
20% for fresh embryos and 15.3% for thawed embryos.
In ICSI, the number of embryos transferred in women aged < 35 affects the TEC and the implantation rate in a similar
way than in IVF. In women aged 35 – 39 or = 40, the
number of embryos transferred does not affect significantly
the TEC. In a total of 3.282 transferences and 906 clinical
gestations, the miscarriage rate is 17% what does not differ
significantly than IVF.
The TEC with donated oocytes (OD) is not affected by the
age of the receptor, being 34.6% in women aged <35 and
40.3% in those aged =40. The clinical miscarriage rate is
14.6%. The age of the receptors (women aged =35) positively
influences the pregnancy rates.
In ICSI, the number of embryos transferred in women aged <35 affects the TEC and the implantation rate similarly
than in IVF. In women aged 35 – 39 or =40, the number
of embryos transferred does not affect significantly the
TEC. In a total of 3.282 transferences and 906 clinical
gestations, the abortion rate is 17%, what does not differ
significantly in IVF.
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