|
October 09, 2005
Art in Fertility
By Ma. Luisa T. Mangubat, MD
Pregnancy is a result of an egg or ovum (hence "ovulation") from the female being fertilized by the sperm from the male. Simply put, the basic requirements are a normal ovulating woman and a man with normal sperm. Infertility means there is a failure to attain pregnancy. There is therefore a male factor and a female factor as a cause of infertility. Before treatment for infertility can be started, the couple should undergo tests to determine what the cause is so that appropriate treatment for the man, the woman or both can be given.
HOW PREGNANCY HAPPENS
The ovum develops in the ovary and is released at around middle of the menstrual cycle in a process called ovulation. After the egg is released, it goes to the fallopian tube due mainly to the undulations from fingerlike projections called fimbria. It then travels the length of the fallopian tube. After sexual intercourse, sperm deposited in the vaginal canal begin their ascent from the cervix into the uterus then to the fallopian tube where they then meet the egg. It takes only one sperm to successfully penetrate the protective coating of the egg to fertilize it. Once fertilization occurs, an embryo develops from rapidly dividing cells. The embryo continues its travel in the fallopian tube until it reaches the uterine cavity at about the fourth day, floats for another two to three days and finally implants in the uterine wall, resulting in a pregnancy.
SO, WHY CAN’T YOU GET PREGNANT?
For the woman, the problem can start even before ovulation. Hormonal problems can prevent a woman from producing the all-important egg. This requires intensive monitoring and medication. Since the egg comes from the ovary, any problem of the ovary which prevents ovulation to occur should also be corrected. If ovulation does occur, the fallopian tube should not have any problem that prevents egg and sperm to meet, such as blocked tubes due to endometriosis, infection and ligation (as in BTL or bilateral tubal ligation for contraception). Finally, even if there is an embryo, it should successfully implant in the uterus so conditions such as myoma, which can prevent this, should be corrected.
For the man, the usual problem is the absence of sperms (azoospermia) or low/inadequate sperm count (oligospermia). Other problems can be erectile dysfunction (inability to attain an erection), retrograde ejaculation (the sperms go backward instead of being released outward), inadequate volume of semen, poor motility and generally poor sperm quality. Each problem must be carefully identified and corrected.
WHAT IS ART?
(ART) Assisted Reproductive Technique is resorted to when conventional infertility treatments are not successful or feasible.
Artificial Insemination
The simplest form of assisted reproduction is Artificial Insemination (AI) in which the sperm collected from the male is introduced directly into the female reproductive tract through a tube, hence giving the sperms an extra push in their journey to meet the egg. AI can be intravaginal, intracervical, intrauterine, intrafallopian and intraperitoneal, depending on where the sperm are deposited. Many animal pregnancies are already done in this manner such as those done on pigs and horses. It is possible then, say, that this technique was borrowed from the vets. However, strictly speaking, when we talk of ART, it usually means advanced techniques where the eggs used come directly from the ovaries retrieved through special procedures.
In-Vitro Fertilization (IVF) and Embryo Transfer (ET)
This produces what is popularly known as "test-tube baby". The woman’s mature eggs are harvested through transvaginal ultrasound-guided aspiration. The harvested eggs and the collected sperm are left together in a dish or tube for 24 hours and checked to see if fertilization occurred (IVF). If fertilization has occurred, resultant embryo is then transferred to the uterus (ET) from the vagina through the cervix.
Gamete Intrafallopian Tube Transfer (GIFT) and Zygote Intrafallopian Tube Transfer (ZIFT)
This is done only when at least one fallopian tube is healthy. In this procedure, the gametes (mature eggs and collected sperms) are placed in the ampulla of the fallopian tube which is the normal site of fertilization (GIFT). Day-old embryos or zygotes can be also be used (ZIFT). Laparoscopy is used since the sperms/egg or embryo are placed in the site through a laparoscopic catheter.
Intracytoplasmic Sperm Injection (ICSI)
In this procedure, a single sperm is injected directly into the egg by piercing the protective covering of the egg and ensure that the sperm fertilizes the egg. This is preferable for males with very low sperm counts in the ejaculate. If there are no sperms in the ejaculate but are present in the testicles, a biopsy can be done and sperms can be taken directly from the testis (Testicular Sperm Extraction or TESE) or from the tube above the testis called epididymis (Microsurgical Epididymal Sperm Aspiration or MESA).
Embryo Freezing (Cryopreservation)
To increase the likelihood of pregnancy, several eggs are harvested and fertilized. Therefore, there can be more embryos than are needed for a single IVF procedure. The extra embryos are stored in freezers, ready for the next transfer. About 2/3 of cryopreserved embryos survive the thawing process. Pre-embryos for ZIFT can also be cryopreserved.
SUCCESS RATES
The success rates vary from one infertility center to another. IVF-ET has about a 40 percent success rate while that of GIFT/ZIFT is higher at about 60 percent. ICSI results in fertilization rate of about 70 percent but the resultant pregnancy rate is only about 20-35%. Frozen embryo transfer is the least successful with a rate of less than 20 percent probably due to the thawing process. These success rates are from claims of several centers in the USA. In Asia, countries like Japan and Singapore lead the rest in ART but other countries are fast catching up. In the Philippines, there are very few centers where these procedures are done but with good success rates.
We do have specialists in the field of Gynecologic Endocrinology and Infertility. They will be the best persons to consult when you are considering these high tech procedures.However, since these procedures entail a lot of expenses, be sure you are ready to spend for your dream of parenthood.Good luck!
The views expressed herein are solely those of the author. For more information, consult a gynecologist.
DR. MALU TORRALBA-MANGUBAT is a fellow of the Philippine Obstetrical and Gynecological Society and the Philippine College of Surgeons. For personal consultations, her clinic hours are as follows:
At the Medical Center Manila
Room 337, 1122 Gen. Luna cor. U.N. Avenue, Ermita, Manila
Mondays through Saturdays, 10:00 a.m. to 12:00 nn
Mondays through Thursdays, 3:00 p.m. to 6:00 p.m.
Tel. (632) 528-1173
At the Asian Hospital and Medical Center
Filinvest City, Alabang
Room 722, Medical Office Building
Mondays, Wednesdays, Fridays, 8:00 a.m. to 10:00 a.m.
Tel. (632) 722-9340
For comments, e-mail
.
|
E-mail this to a friend
Printer-friendly version
