Obstetrical Services



Testing for Pregnancy

Birth defects affect 3-4% of all pregnancies. Some, but not all, of the possible birth defects can be discovered by blood tests, ultrasound and genetic testing.

The testing that you decide to perform for your pregnancy is an individual choice based on many factors such as your health, age, previous pregnancy experiences, family’s health history and the number of fetuses you carry.

There are two types of testing for your pregnancy: screening/non-invasive and invasive testing.

Screening and Non Invasive Testing

Screening tests have no risk to the fetus or the mother. Screening tests include blood tests and ultrasound. Screening tests can identify a women who is at higher risk than expected of having a baby with a birth defect, but cannot detect all of these birth defects (such as spinal cord defects or heart problems).

First trimester (11-13 weeks) screening tests includes a blood test combined with an ultrasound. This testing can detect up to 85% of Down’s syndrome and up to 98% of Trisomy13, Trisomy 18 and Turner’s syndrome. This test is performed at another doctor’s office.

For women over 35 or with a personal or family history of chromosomal defects a blood test is available at 10-18 weeks which identifies more than 99% of fetuses with the four most common genetic defects: Down’s, Trisomy 13, 18 and Turner’s syndrome.

Second trimester (15-20 weeks) screening blood test called a MSAFP is done at 15 weeks in our office. This test predicts fetal risk for spinal cord defects (neural tube defects), Down’s syndrome and Trisomy 18.

At 18-20 weeks an ultrasound will confirm your baby’s growth, your due date and can detect 35% of fetal birth defects, but misses 65% of all birth defects.

Invasive Testing

Invasive tests have a very small risk to the fetus and an extremely rare risk to the mother. Invasive tests include chorionic villous testing and amniocentesis. Invasive tests can diagnose chromosomal birth defects in the fetus (such as Down’s syndrome).

First trimester invasive testing is called a chorionic villous sampling (CVS). A small catheter is passed through the cervix under ultrasound guidance to obtain a small sample of the placenta which contains the baby’s chromosomes. Results in 7-10 days. Risk of miscarriage is 1 in 200.

Second trimester invasive testing is called an amniocentesis. This test is performed by inserting a needle through the mother’s abdomen into the uterine cavity to obtain fetal cells.

Results in 7-10 days. Risk of miscarriage is 1 in 250.

We can refer you to a genetic counselor for more information on invasive testing if needed.

All testing is optional and is your personal choice.

This information is provided to help you make your appointment for first trimester screening for chromosome abnormalities. First trimester screening is performed between 11 and 13 weeks.

Call their office now to make your appointment(s).

It is wise to check with your insurance carrier to see which office accepts your insurance and to verify coverage of any testing you desire.

Phoenix Perinatal Associates/Obstetrix
Drs. Clewell, Perlow, Strong, Bowen, Kuhlman….
Appointment scheduling                                                    1-888-890-3066

 3877 N. 7th St. #400 Phoenix 602-257-8118
1840 S. Stapley Drive #131 Mesa 480-969-5999
6320 W. Union Hills Dr. #B1400 Glendale 623-561-0043
10210 N. 92nd St. Bldg. 3 #105 Scottsdale 480-661-1332
600 S. Dobson #D-34 Chandler 480-969-5999

Valley Perinatal
Dr. John Elliott

2942 N. 7th Ave. #102 Phoenix 602-942-0600
9440 E. Ironwood Square Dr. Scottsdale 480-551-9700
4864 E. Baseline Rd. #101 Mesa 480-467-2150
2242 W. Southern Ave. Mesa 480-491-1600

Arizona Genetic and Fetal Medicine
Dr. Gary Simpson

6301 S. McClintock Dr. #115 Tempe 480-897-0234

St. Joseph’s Perinatal Services
Drs. Balducci, Blumrick, Solomon…

500 W. Thomas Rd. Phoenix 602-406-7048
1727 W. Frye Rd. #210 Chandler 480-728-2222


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