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Fertility Changes with
Surprising news for both men and women: your biological clocks have
been ticking for longer than you think. The results of recent research
show fertility begins to decline in women as early as age 27 and in men
around age 35. But the news isn't all bad; the fertile period (or open
window for conception) during a woman's cycle remains the same length
between ages 19 and 39.
The study, published in the May 2002 issue of the journal Human Reproduction,
involved 782 European couples practicing the rhythm method of contraception.
Women recorded their daily body temperatures, the days they had sex,
and the days of their menstrual bleeding. Fertility was measured by the
probability of becoming pregnant per menstrual cycle.
Analysis of the results showed women under the age of 27 had a greater
than 50% chance of becoming pregnant during a menstrual cycle, assuming
their partners were the same age and they had sex two days before ovulation,
which is the best time for conception. This probability dropped off notably
at the age of 27. Women ages 3539 were nearly 50% less likely to
become pregnant during a cycle than women under 27.
Scientists have speculated that the decrease in women's fertility with
age was a result of a shortened fertile period during the menstrual cycle.
Yet, the results of this study show this is not the case. For women ages
1939, the fertile period (when chances of conception were greater
then 5%) occurred during the 6 days prior to ovulation.
The researchers also found women age 35 with partners of the same age
were 29% likely to become pregnant on their most fertile day, while women
age 35 with partners five years older were only 18% likely to become
pregnant. This indicates the fertility of men begins to drop sometime
during their late 30s. The researchers indicate many reasons may be responsible
for this decrease, including genetic defects in the sperm or structural
changes in the testes and prostate.
Experts say that this study is not a cause for alarm. The results show
an average decline in fertility as women and men age. At any age, however,
fertility levels vary widely among individuals. In general, as women
age, they should expect it to take longer to become pregnant than when
they were younger.
June 2002 Update
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may cause birth defects, low birth weight
It's been 24 years since the first baby was conceived with the help
of in-vitro fertilization (IVF), bringing hope to thousands of childless
couples. In 1999 alone, over 30,000 babies were born in America with
the help of artificial reproductive technologies (ART), including IVF.
Since then, an estimated 300,000 IVF babies have been born worldwide.
But this revolutionary way to overcome infertility is not risk-free.
Two new studies published in the March 7, 2002, issue of the New
England Journal of Medicine suggest that ART babies are more likely
to be born with birth defects and low birth weights than newborns conceived
In IVF the man's sperm and the women's egg are combined in a laboratory
dish. After fertilization, the resulting embryo is then transferred to
the women's uterus to develop naturally. A special IVF procedure called
intracytoplasmic sperm injection (ICSI), where the sperm is injected
directly into the egg, can also be used for severe male infertility.
ARTs, including IVF, increase the risk of multiple births because several
embryos are usually transferred to the uterus at one time to increase
the probability of a successful pregnancy. But this practice is controversial
because multiple births are associated with low birth weight, which puts
the newborn at an increased risk for short- and long-term disabilities
and even death. However, in one of the new studies, researchers with
the U.S. Centers for Disease Control found that even ART babies born
alone were 2.6 times as likely to have a low birth weight than a naturally
conceived single infant.
In the other study, Australian researchers found that about 9% of the
301 IVF babies studied had birth defects, such as heart trouble, stunted
limbs, Down syndrome, and cleft palate, compared to only 4.2% of the
4,000 naturally conceived babies studied. The risk was still more than
doubled when multiple births were not considered.
Neither these nor previous studies have been able to identify whether
the reason for the excess risk of low birth weight and birth defects
is related to the underlying infertility itself or to the procedures
and drugs used to overcome it.
To many advocates of assisted reproduction, the results of these studies
aren't necessarily frightening, but reassuring. They look at them and
celebrate that more than 90% of IVF babies are born healthy. But regardless
of the interpretation of the numbers, couples looking for help with fertility
should consider these risks.
May 2002 Update
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Shapely Sperm and Fertility
The shape of a man's sperm is the best gauge of fertility,
according to a recent study in The New England Journal of Medicine.
Researchers from the National Cooperative Reproductive Medicine Network
have found the best sperm structure is an oval head and long straight
tail. Unusually shaped sperm those with very large or small heads,
or tails with twists and coils were not able to fertilize the
egg. The World Health Organization (WHO) publishes standards of normal
semen measurements, but the guidelines on the quantity of quality semen
indicative of fertility have varied throughout the years and have not
proved themselves in thorough testing.
The men in the study were more likely to be infertile if fewer than 9
percent of their sperm were well shaped, while they were most likely
to be fertile if more than 12 percent of their sperm looked normal.
While there is no surefire way to diagnose fertility, these findings
on well-shaped sperm could help standardize the WHO's criteria.
December 2001 Update
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Hormone Level Best Predictor of Drug
Success in Treating Ectopic Pregnancy
The prevalence of ectopic pregnancies has risen sharply
since the 1970s. Some women are at increased risk for an ectopic pregnancy
for example, women who smoke, or have had prior pelvic surgery,
or have used an IUD in the past, and those with a history of infertility.
An ectopic pregnancy occurs when an embryo starts to develop outside
the uterus, usually in a fallopian tube. This quirk of nature is difficult.
The embryos are rarely normal, and it is impossible for the pregnancy
to continue. This situation also threatens a woman's health. If an ectopic
pregnancy goes undetected, the fallopian tube could rupture and the woman
could suffer severe internal bleeding. If it is not detected early enough,
there can be damage to the woman's reproductive organs that can compromise
her fertility. Symptoms of an ectopic pregnancy may include vaginal bleeding,
sharp abdominal cramps, or pains on one side; however, ectopic pregnancy
can be painless or associated with only mild cramps.
An ectopic pregnancy is generally treated with surgery, which is invasive
and carries certain risks. Another approach is the use of a drug called
methotrexate. Methotrexate is traditionally used as part of cancer therapy
because it obstructs the metabolism of rapidly growing cells. In the
case of an ectopic pregnancy, the drug prevents embryonic cells from
multiplying. While there are clear advantages to medical treatment of
an ectopic pregnancy (no surgical risks, faster recovery time, and possibly
better preservation of fertility), it isn't always effective and sometimes
surgery is required.
Researchers from the University of Tennessee, Memphis, recently did a
study to determine what factors might help predict whether methotrexate
treatment will be successful. They monitored 350 women with ectopic pregnancies
who were given the drug; 320 of the women were treated successfully.
After comparing various factors, such as the size of the embryo and the
presence of fluid in the abdominal cavity, the researchers determined
that the level of a hormone produced during pregnancy was the single
most important factor in determining whether drug treatment would be
successful. The hormone, called human chorionic gonadotropin (HCG), is
produced by the placenta and helps ensure the production of progesterone,
thus preserving the pregnancy. (It is the hormone measured in home pregnancy
tests.) High levels of the hormone suggest an embryo that is still developing
and growing. Methotrexate treatment was more successful in women whose
HCG levels were 15,000 or less. It is important to keep in mind that
the women in this study had very early ectopic pregnancies and no signs
of internal bleeding.
Ectopic pregnancy can be a painful experience both emotionally and physically.
Medical treatment with methotrexate, rather than surgery, can be a somewhat
less traumatic way to handle this problem.
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New Fertility Drug Ovidrel (R) Expected to Hit
Market in 2001
Ovidrel (R) the first fertility drug to contain recombinant human
chorionic gonadotropin has been approved for subcutaneous injection.
If all goes according to plan, Ovidrel (R) will be available for patient
use sometime in 2001.
For the past 40 years, human chorionic gonadotropin, collected from the
urine of pregnant women, has been the only hormonal preparation commercially
available to help trigger ovulation in women with infertility due to
anovulation. For the past 20 years, the urine-derived human chorionic
gonadotropin (uHCG) has also been used to promote final maturation of
eggs in the ovaries of women undergoing assisted reproductive technologies
such as in-vitro fertilization. Commercial preparations of uHCG have
suffered from batch-to-batch inconsistency, which can lead to variations
in response not only from patient to patient but also within one
patient from cycle to cycle. In contrast, Ovidrel has a high level of
purity, which means that its strength and accuracy can be measured precisely,
and that it can be produced uniformly. According to a recent study, Ovidrel
is just as efficient as uHCG in terms of number of eggs produced in women.
But, in producing mature eggs, Ovidrel (R) was found to be more efficient.
One clear advantage to using Ovidrel is the fact that the women in the
study had a much better tolerance locally to its injection. The uHCG
injections must be administered intramuscularly (a deep shot, requiring
a long needle), rather than just under the skin, as Ovidrel requires
(using a needle similar to that used for insulin injections). For women
in the study, administration of uHCG was four times as likely to cause
adverse events, such as pain, inflammation, and bruising at the injection
site when compared with the subcutaneous injection of Ovidrel. Even women
who had suffered an adverse local reaction to uHCG were able to tolerate
the injection of Ovidrel much better. Women's improved tolerance of Ovidrel
is clearly a plus in terms of comfort and ease of use, in addition to
its clinical benefits.
October 2000 Update
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The Benefits of Bed Rest after Intrauterine
A randomized study conducted in Quebec, Canada, is the
first to demonstrate that bed rest after intrauterine insemination (IUI)
increases the rate of successful conception. Out of 116 couples chosen
to participate in the study, 95 completed it (all of whom were diagnosed
with "unexplained infertility"). The women were all younger
than 38 years old, had their ovulation confirmed, and had open fallopian
tubes. The men all had a normal semen analysis. The couples had experienced
infertility for between one and three years and were randomly assigned
to two groups.
Patients in each group received the same treatments, screenings, and
drugs in the same doses at the same time in their cycles, for a maximum
of three treatment cycles. Patients in group I were allowed to get up
immediately after IUI, while patients in group II were asked to remain
lying on their backs for 10 minutes after the procedure. Group I was
made up of 40 couples; four of the women in this group became pregnant.
Group II was made up of 55 couples; 16 of the women in this group became
Researchers are not exactly sure why 10 minutes of bed rest made such
a difference in the rate of pregnancy between the two groups. One reason
they offer is that standing and moving around after IUI might cause most
of the sperms to be expelled from the uterus and vagina. Study investigators
could not say just how much bed rest is "best" but believe
that 10 minutes seems to be enough. They also suggest that 10 minutes
of bed rest after sexual intercourse might also increase the chance of
conception. In light of these findings, these researchers recommend that
10 minutes of bed rest after IUI become standard practice.
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