Karen and her husband were told after their 2nd child that another pregnancy could mean death to the fetus or herself. God had other plans though. A son was born to them soon after and a few years later they were blessed with twin daughters. God is not limited by medicine or science. He can do whatever He wants. 

St Gianna Beretta Molla was a physician, a working mom, professional woman, and a loving wife.
In September of 1961, at the age of 39, Gianna was pregnant with her fourth child when physicians diagnosed a large ovarian cyst which required surgery. The surgeon suggested that Gianna undergo an abortion in order to save her own life. Gianna's decision was prompt and decisive: "I shall accept whatever they will do to me provided they save the child." She underwent the surgery but her fate was sealed. The following year, on Good Friday, Gianna was admitted to Monza Maternity Hospital. Her daughter, Gianna Emanuela, was born the next day but Blessed Gianna expired seven days later, on April 28, 1962. She was canonized by Pope John Paul II on May 16th 2004. Here's a link to her Web site.
She was a "martyr of maternal love." Jesus said that there is no greater love than giving one’s life for one’s friends…

For more miraculous baby stories, click on the articles below:

You can read this article relating how a mother diagnosed with cancer refused to abort and refused to receive cancer treatment so that her baby could live.

Check also at this more extraordinary article showing how twin babies in the womb saved their mother from cancer!

We need to re-learn to trust in God who alone can decide.