ZAHN: Our top story in health tonight concerns many of the tens of thousands of American women who take anti-depressants during pregnancy. Well, tonight, the American College of Obstetricians and Gynecologists has just issued a warning that pregnant women and women planning to get pregnant should avoid the anti-depressant Paxil. The reason: potential birth defects.

Here's senior medical correspondent Dr. Sanjay Gupta with one of the first families to file a lawsuit over this. His exclusive report is tonight's "Vital Signs".

(BEGIN VIDEOTAPE) DR. SANJAY GUPTA, CNN MEDICAL CORRESPONDENT (voice-over): From his very first breath, Adrian Vasquez has fought to stay alive.

MATILDA VASQUEZ (PH), ADRIAN'S MOTHER: I was scared to death. I was just hearing all these machines and beeps.

GUPTA: Just before his birth, Adrian's parents Anthony and Matilda received stunning news from their doctor.

M. VASQUEZ: She says, I'm sorry, honey, she's like, but there's something wrong with your baby's heart.

UNIDENTIFIED FEMALE: Are you ready?

GUPTA: Adrian was born with a double outlet on his right ventricle. That's a potentially deadly condition that restricts oxygen from getting through his body.

ANTHONY VASQUEZ, ADRIAN'S FATHER: You see something wrong with your child, you know, what are you going to do to fix it? When you can't fix it, you know, what are you going to do?

I know, buddy.

GUPTA: Now, two and a half, Adrian has endured three open heart surgeries. A pacemaker keeps him alive.

A. VASQUEZ: Good job.

M. VASQUEZ: Careful.

GUPTA: The family says it has no history of heart disease. Matilda says she did everything by the book during her pregnancy. Then Matilda started to wonder. Did Paxil, the pill that she took for anxiety, possibly cause Adrian's problems?

She says when she got pregnant, she asked the doctor if it was OK to keep taking it.

M. VASQUEZ: I said, so it's safe? And he said, yes.

GUPTA: Then late last year, Anthony searched the Internet. In December of 2005, the Food and Drug Administration issued a public health advisory about Paxil.

The FDA said early results from two studies suggested women who took paroxetine, which is available under the brand name of Paxil, during the first three months of pregnant were one and a half to two times as likely to have a baby with a heart defect as women who received other anti-depressants or women who simply didn't take anti- depressants.

In July, the family sued GlaxoSmithKline, the makers of Paxil. The Vasquez's attorneys believe the company was aware of the drug's risk before Adrian was band didn't do enough to warn doctors or expectant mothers. A. Vasquez: I mean, how long did they know about this? You know, did they know way before, you know, whenever the memo came out?

GUPTA: GlaxoSmithKline declined to comment on the lawsuit. But in a written statement, said it "has diligently monitored the safety of Paxil before and after its approval by the FDA in 1992."

A company internal study released in 2005 and shared with the FDA found a 1.5 fold increased risk for heart malformations for Paxil compared to other anti-depressants.

To be clear, normally the risk of giving birth to a child with a heart defect about 1 percent. That increases to between 1.5 to 2 percent for patients taking paroxetine in the first trimester.

At the urging of the FDA, GlaxoSmithKline changed Paxil's labeling in September of 2005 to warn about the risk of birth defects. For some women, getting off an anti-depressant can be excruciating. And there is a chance the mother could harm herself or her unborn child.

DR. LILLITH SHAPIRO, OB/GYN: I think patients need to know that they're taking a risk. But they need to know that they're also taking the risk by not taking the medication.

DEBORAH CLOANINGER, TOOK SSRI WHILE PREGNANT: Baby, you want to mow the lawn?

GUPTA: Deborah Cloaninger is one Dr. Shapiro's patients.

CLOANINGER: I would stay up thinking about my children's mortality and how they might die.

GUPTA: After giving birth to her second child, she went on Zoloft. Deborah continued taking it while pregnant with her third child, Lillian. She says she has no regrets about taking an anti- depressants.

CLOANINGER: The benefits have definitely outweighed the risks. I think indirectly, more harm could have happened to my unborn child had I gotten off of it.

UNIDENTIFIED MALE: Whoops.

GUPTA: But for Matilda Vasquez, that's a risk she would have been willing to take.

M. VASQUEZ: Good boy.

He's going to need surgeries for the rest of his life. You can never assume that it's not going to happen to you.

Hi.

(END VIDEOTAPE) ZAHN: But Sanjay, what is so heartbreaking about this is that women have to make some very individual decisions here, particularly if they think they can't cope without this medication. So walk us through how they try to avoid these mine fields here.

GUPTA (on camera): Yes, Paula, it's a very delicate situation. I think everyone's been cognizant of that. I think there's a few questions. We tried to boil it down in terms of what women, their families, their doctors should all be asking themselves when making decisions, specifically about anti-depressants and pregnancy, and even more specifically about Paxil.

First of all, how serious is your condition? Is it one of those situations where you feel kind of blue sometimes? Or do you have full-blown depression, diagnosed depression?

There is a concern about over usage of anti-depressants in this country. Do you fall into that category or another category?

Another question to ask is how long have you been on the medication, as well. And if you've ever off of it, if you've done a trial period off of it, how did that go for somebody? Were you able to tolerate that OK?

And finally, what are your other options? I mean, there are other anti-depressants which might be safer, as we talked about in the piece, but also could talk therapy be an option for somebody as well, getting off the medications altogether.

It is not easy, Paula. Having a therapist when you go off the medication or switch over, really, really important.

ZAHN: Thank you for better educating us tonight.

Dr. Sanjay Gupta.

GUPTA: Thank you.

ZAHN: I love that free house call.

We're going to take a short break.

We'll be right back.