The death of "Sheryl" Roe - and a question

"Sheryl" was 23 years old when she chose abortion. She had a history of sickle cell anemia and three live births. She was in her first trimester of pregnancy when she underwent the abortion on July 11, 1970. Nine days later, July 20, she died from sickle cell crisis.

It is only today, blogging about Sheryl, that I noticed something strange. The three abortion-precipitated sickle cell deaths I know of all took place almost exactly a year apart: Sheryl on July 20 of 1970, Betty Hines on July 19 of 1971, and Margaret Davis on July 15 of 1972.

I wonder -- Why are all three women with this cause of death clustered like this? Why are there no abortion-precipitated sickle-cell deaths in my files that took place after Roe vs. Wade?

There are some theories that can be put forth:

1. These three deaths were a lesson, and abortion doctors learned from them, and they were careful and alert to signs of sickle cell crisis, and they henceforth aborted all at-risk patients in properly equipped hospitals, and correctly diagnosed and treated any sickle cell crisis, preventing any more sickle-cell deaths triggered by abortion.

2. The three deaths were total flukes, and it's just a total coincidence that they took place almost on the same date three years in a row then never again thereafter.

3. Abortion techniques changed with Roe, and the new techniques no longer triggered sickle-cell crises.

4. The rise of outpatient abortion facilities after Roe meant that the doctor treating the woman for the sickle-cell crisis was unlikely to be the same doctor who'd done the abortion. The treating physician was focused on trying to save the woman's life, not trying to figure out what triggered the crisis, and was thus not likely to connect the fatal crisis to the precipitating abortion.

5. Careful research revealed that abortion can't trigger sickle-cell crisis after all; these three deaths were mistakenly connected with abortion by ill-informed physicians.

6. My data-collection system has holes in it, and there are other deaths like Margaret's, Betty's, and Sheryl's that I'm just not aware of.