JUST MAKING SURE DOCTORS ARE WORKING TO MAKE PRENATAL TESTING AS PAINLESS AS POSSIBLE.

Byline: Evan Henerson Staff Writer

So you're pregnant? Congratulations, says your doctor. Now drink this, strap yourself to this machine, step on this scale. We'll need blood, urine and the all-important family history. This may taste funny. Now this one will sting. We'll call you with the results in a couple of weeks.

Feel like a pin cushion? A lab rat? That's natural. You're testing for two.

The good news is doctors and researchers are constantly working to make the process more efficient and more comfortable.

Diagnostic and screening tests have long been a routine part of the prenatal process, designed to rule out all sorts of conditions - from genetic abnormalities like Down syndrome to spina bifida and Tay-Sachs disease. Typically, the older a woman is, the greater the risk to her child and the more tests her obstetrician will recommend she undergo. Ethnic background and family medical history also play significant roles.

The results of swab tests, urinalysis and other procedures are analyzed to measure a veritable alphabet soup of medical conditions: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3). Positive results generally mean the news isn't good.

``It sounds like a lot. It is a lot,'' says Dr. Karen Filkins, director of reproductive genetics in the department of obstetrics and gynecology at UCLA. ``It's very individually tailored. Someone looks over each patient to decide what they need.''

By now, Sheila Oasay knows the drill. Expecting her fifth child in April, Oasay says she follows the recommendations of her doctor, Eldridge Pearsall, director of the New Arrivals program at Northridge Hospital Medical Center's Sherman Way campus in Van Nuys.

``You can refuse the testing. You don't have to do it. You have a choice,'' says Oasay, 38, who lives in Burbank. ``It just puts me at ease, and I trust my doctor with everything. If he told me to stand on my head, I probably would.''

In the case of four out of five of Oasay's pregnancies, Pearsall has recommended an amniocentesis, a frequently performed diagnostic test designed to locate the presence of chromosome abnormalities such as Down syndrome. The test, which involves inserting a needle into the abdomen to collect a sample of amniotic fluid, is recommended for women over 35, but Oasay said the presence of retardation in her family's background made the test important even before she got into the higher-risk age range.

Considered by most physicians to be the ``gold standard'' of tests, amniocentesis - or ``amnio'' - was performed on more than 112,000 women in 1998 - the most recent year for which data are available. One recent study suggests many women might be undergoing amniocentesis unnecessarily. The study, led by Dr. Rebecca Smith-Bindman at the University of California, San Francisco, found that of seven markers on ultrasound tests thought to increase the risk of Down syndrome, only one was found reliable enough to justify an amnio.

This causes some concern because the procedure - performed in the second trimester, usually at 14 to 16 weeks - poses the slight possibility of causing infection, leaking or a miscarriage. Nearly all insurance companies will pay for the test if the patient is over 35 or otherwise considered to be in a high-risk category.

Considered just as invasive as amnio, chorionic villus sampling, or CVS, requires a catheter to be inserted into the abdomen or vagina to take a tissue sample from the placenta. This procedure can be done earlier in the pregnancy (in the ninth to 11th week) and yields less data, but the results can be determined faster. CVS also carries a slightly higher risk of causing pregnancy complications than the amnio.

And new tests are in the development phase with researchers constantly looking for ways to administer tests less painfully and earlier in the pregnancy. The sooner a woman can rule out the possibility of complications, researchers say, the more comfortable - physically and psychologically - she is likely to be through the remainder of the pregnancy. And if there is a high risk the child will be born with birth defects, the sooner a woman knows, doctors say, the easier it will be for her either to prepare herself or terminate the pregnancy.

Filkins has studied a combination finger-stick blood test and ultrasound test designed to locate signs of chromosome abnormalities that could indicate Down syndrome or trisomy 18. Performed during the first trimester, the test is designed to locate for analysis the same chemicals that the triple marker screen - taken during the 15th to 20th week - will detect. Also called the maternal serum screening test, the triple marker looks for the presence of three chemicals, the levels of which may indicate the possibility of a chromosome or neural tube defect.

The first-trimester blood/ultrasound screening is still in the investigational stage, and therefore ``so dependent on operator skills and proper technique,'' says Dr. John Williams III, co-director of the Department of Reproductive Genetics at Cedars-Sinai Medical Center. ``It appears it is going to be a very good, very useful test once individuals are properly trained to perform it.''

Williams also points out that the early test is ``a screening test, not a diagnostic test. You can get very close, but the results picked up on the ultrasound have to be confirmed. Amniocentesis and CVS are diagnostic tests. By nature, they're also invasive.''

The discomfort factor is enough to scare some patients away from certain tests, says Northridge's Pearsall, who admits that having somebody come at you with a 3 1/2-inch needle can be daunting, no matter how much training the technician has had.

Women who are determined to complete a pregnancy regardless of what a diagnostic test reveals can balk at any kind of test. But the ``I don't want to know'' argument isn't a strong one, according to Pearsall.

``I try to tell the patients that we're not really trying to find people that need to have an abortion to eliminate defective babies,'' he said. ``We're trying to find as many problems as we can before the baby is born. With Down syndrome, you can have cardiac defects and various other things. Parents can get some counseling, so they're emotionally prepared to have a baby with Down syndrome.''

As she sat in Pearsall's office, listening to him discuss potential Down syndrome-related complications, Morassa Dabirian said she became increasingly convinced of the need for an amnio in her second trimester.

Dabirian will be 42 when she delivers her child - her third - in October, and she says she'll continue her pregnancy regardless of the test results.

But the risk factors associated with her age worry her more than her concerns over potential complications from the test itself.

``My husband is against (having the amnio),'' she admits. ``He says whatever the baby is, it's our baby, and we will carry it, but I want to do it because I want to know the health of the baby. We need to be prepared in case there's something wrong.''

According to Williams at Cedars-Sinai, patients facing any type of invasive screening test should carefully screen the person performing the procedure by asking how much experience the doctor has had, if he is state approved, how many procedures he performs per month and per year.

``Many independent physicians may do one CVS procedure every two to three months,'' said Williams. ``That's probably not enough to maintain the skills.''

Tests: What's available

Routine screenings take place at every stage of a woman's pregnancy. When and how they're performed, and what doctors are looking for:

Blood pressure: Performed at every prenatal visit via a blood pressure gauge. Increased blood volume and fetal blood circulation that occurs in pregnancy increases the demands on the mother's cardiovascular system. High blood pressure, or pregnancy-induced hypertension, can lead to preterm labor; reduced kidney function; or separation of the placenta, leading to bleeding and reduced blood flow to the baby and to possible retarded growth and development.

Gonorrhea, chlamydia and syphilis: A swab test performed during the first trimester, at up to 12 weeks of gestation. These three sexually transmitted diseases can affect an unborn baby if a mother is infected. They can cause a miscarriage or infect the baby during the delivery.

Blood type and antibody screen: Performed during the first trimester, the test determines whether the mother and baby's blood are compatible. If they are not, the mother may need to receive an injection to prevent her blood from reacting badly with the baby's.

Urine screen for sugar and protein: A urine check is typically done at each prenatal visit. A high sugar level may be a sign of gestational diabetes. Protein in the urine can mean bladder or kidney problems.

Glucose tolerance screening: Conducted between the 24th and 28th week. Abnormally high levels of sugar in the mother's blood may be passed to the baby and cause it to develop breathing problems after birth. Gestational diabetes can be controlled with a special diet and/or insulin injections.

Triple marker screen: A blood test conducted during the second trimester. This test measures levels of human chorionic gonadotropin (hCG), alpha-fetoprotein (AFP) and estriol. The levels of AFP and estriol typically rise during the second trimester, while hCG decreases. Measuring all three levels gives information about the risk for birth defects such as Down syndrome, and neural tube defects like spina bifida.

Amniocentesis: Optional test performed during second trimester, usually at between 15th and 18th week. A diagnostic test for women over age 35 who have a higher-than-usual risk for genetic disorders or whose AFP or triple screening tests results were suspicious. After an ultrasound determines the position of the baby, a needle is inserted into the abdomen to remove a sample of amniotic fluid. Analysis can detect neural tube defects and genetic disorders. Amniocentesis is sometimes used later in pregnancy to determine fetal lung maturity in high-risk cases. The procedure carries a slight risk of infection or miscarriage.

Chorionic Villus Sampling (CVS): Optional test performed in the ninth to 11th week. A catheter inserted in the abdomen or vagina obtains a section of the placenta. As with an amniocentesis, analysis can detect neural tube defects and genetic disorders. This procedure also carries a slight risk of miscarriage.

Fetal monitoring: Performed during the third trimester, usually in high-risk pregnancies, preterm labor or overdue babies. An electronic monitor is strapped to the mother's abdomen to measure the fetal heartbeat, mother's heartbeat and mother's uterine muscle contractions. A nonstress test and a stress test - designed to increase the baby's heart rate - help determine how well the baby will handle the stress of delivery.

Ultrasound: Performed at all stages of pregnancy. As early as six weeks, Doppler ultrasound can be used to detect the baby's heartbeat. Between 18 and 22 weeks, during a routine ultrasound exam, a hand-held transducer is moved against the outside of the mother's abdomen, and the baby, placenta and amniotic sac can be visualized.

During an ultrasound, a doctor can confirm the gestational age of the baby, and often determine its sex. Ultrasound can also be used to diagnose or rule out complications later in pregnancy.

CAPTION(S):

3 photos, box

Photo: (1 -- cover -- color) Testing for two

Pregnancy brings a litany of screenings meant to ensure the health of mother and baby

Charlotte Schmid-Maybach/Staff Photographer

(2 -- 3) Sheila Oasay, Burbank, undergoes an ultrasound screening test, like the one shown (inset) from another patient. The test is being administered by Dr. Eldridge Pearsall in his Van Nuys office.

Tina Burch/Staff Photographer

Box: Tests: What's available (see text)

Sources: American Association of Clinical Chemistry, epregnancy.com and howstuffworks.com