Hello Volcano, and thank you for your questions.
I'll tackle your questions in order. First up: "Is there a way of
having twins or does it have to be natural?"
As a mother of twins, I have been asked this question several times.
Sometimes by women who really want to have twins, and sometimes people
wondering if I did this to myself on purpose. (Uh, no.) For whatever
reason, some really do believe that having twins is the answer to
creating a quick family with just one pregnancy, or they just like the
novelty or curiosity of it all. If one were determined, and had access
to a doctor for whom ethics was just another word in the dictionary,
there would be ways to combine certain drugs and/or technology to in
effect make the odds of a multiple birth more likely. Judging from
statistics, I doubt this ever really happens. Given the emotional,
financial, and physical stress a multiple birth has on the mother and
her family, I would seriously reconsider going to extremes to produce
such an outcome.
"Multiple Gestation Pregnancy" (Resolve)
http://www.resolve.org/pregparent/multiples/multiples1.shtml
With about 1 in ~35 pregnancies (depending on race and location)
resulting in twins, the occurrence is still pretty rare. However this
number has risen substantially in the past 20 years, due to increased
availability of reproduction assistance and better pre- and neonatal
care for twins.
"Multiple Births Multiply During Past Two Decades" (National Center
for Health Statistics)
http://www.cdc.gov/nchs/releases/97facts/triple2.htm
My own research on how *not* to conceive any more twins has led me to
the conclusion that one not control or predict how many eggs are
present and available for fertilization in unassisted (i.e. by a
reproductive endochronologist or fertility specialist) circumstances.
Even with such assistance such as IVF (in vitro fertilization) and
ovulation-inducing drugs, there is no way to control how many of
those embryos actually implant and result in a full-term pregnancy and
live birth.
That being said, there are groups of women who will have a higher
tendency to have multiple births than others. These include women who
have fraternal or identical twins in their family line, women who have
had 3-4 previous pregnancies, women who have had at least one multiple
pregnancy, women who are between ages 35-40, women who are overweight,
and women in the Yoruba tribe in Africa. "Their diet consists of large
amounts of a particular species of yam (Dioscorea rotundata). This yam
contains a high level of a substance similar to the hormone estrogen,
which is thought to bring on multiple ovulation."
"Incidence of Multiple Births" (NOMOTC)
http://www.nomotc.org/incidence.html#incidence_twins_by_twin_type
Women with fraternal twins in their families already have been shown
to have increased levels of FSH (follicle stimulating hormone) around
the time of her ovulation. This abundance of FSH can stimulate the
ovary to release more than one egg at a time, or the ovary will go
through two separate ovulation events thus releasing two eggs 24-48
hours apart. These eggs, if fertilized and implanted successfully in
the uterus, will result in fraternal twins. Fraternal twins are as
genetically alike as any siblings in a family. Women over age 35 and
overweight women store more FSH, accounting for these groups to have a
higher occurence of multiple births.
Weschler, Toni. Taking Charge of Your Fertility by Toni Weschler
(Quill, 2001 revised edition)
http://www.tcoyf.com/products/bookstore.asp
The indidence of identical twins has not been proved to be inherited
or in any way affected by genetic, physical or environmental causes.
However, studies are being done to explain the tendency in some
families for high rates of identical twinning.
***
Next question: "Also what are the chances that the child of an
epileptic father is epileptic?"
The answer to this question really depends on a few variables, all
regarding what the cause of the father's epilepsy may be. His could be
the result of a brain injury such as a tumor or trauma, but it could
also be unexplained. Most occurrences of unexplained epilepsy, or
"idiopathic" epilepsy, are the result of genetic mixed with
environmental factors. Children of epileptic parents are twice as
likely to have the condition (2%-8%) than are those in the general
population (1%), though as you can see these rates are very small.
It's much more likely that the child will not be epileptic (92-98%).
For more detail and descriptions of the various types of inheritance
specifically relevant to epilepsy, please see:
"Genetics of Epilepsy - Basic" (GeneInfo)
http://www.geocities.com/geneinfo/conditions/epilepsyb.html
Many genes are involved to produce epilepsy in a person, so many that
it is hard to trace any one type of epilepsy to any one gene. Some
family members may have the condition and exhibit symptoms, while
another may just be predisposed to it. With so many genes in play, the
combinations are many. When you add environmental influences to the
mix, the combinations increase exponentially.
"The Genetics of Epilepsy" (Discovery Health)
http://health.discovery.com/minisites/dna/epilep.html
Several studies on genetics and epilepsy have been carried out using
dogs. Carrying out such research in a controlled environment can lead
to quicker results to demystify what is still a very mysterious
condition.
"Genetic Research Strategies: The Example of Canine Epilepsy"
(NetPets)
http://www.netpets.com/dogs/healthspa/epilepsy.html
Additional resources:
[ MULTIPLE BIRTHS ]
"Twins, Triplets, Multiple Births" (MEDLINEplus)
http://www.nlm.nih.gov/medlineplus/twinstripletsmultiplebirths.html
"I'm Pregnant! I'm Pregnant! How Twins are Conceived" by Sharon Anne
Waldrop (Aug 2001, West Coast Fertility Centers)
http://ivfbaby.com/news/archive/2001_08.htm
"Fertility Drug Treatment" (Healthy Women)
http://www.healthywomen.com/pregnancy/infertility_treatment.html
"Study links multiple births to genetic mutation" By Kathryn Warden (U
of S News)
http://www.usask.ca/communications/ocn/sept15-00/research.shtml
[ EPILEPSY INHERITANCE ]
"Epilepsy -> Inheritance patterns" (Contact a Family)
http://www.cafamily.org.uk/Direct/e33.html
"Inheritance" (Epilepsy Action)
http://www.epilepsy.org.uk/info/inherfrm.html
"Epilepsy: One of the Nation's Most Common Disabling Neurological
Disorders" (CDC)
http://www.cdc.gov/nccdphp/epilepsy.htm
"Epilepsy" (MEDLINEplus)
http://www.nlm.nih.gov/medlineplus/epilepsy.html
Search strategy:
[personal bookmarks]
FSH twins
multiple births statistics
epilepsy inheritance genetics
I sincerely hope this answer is of use to you. Please don't hesitate
to ask for clarification if you need further assistance.
Best regards,
mother-ga |
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