The study also showed that women who had previously given birth were twice as likely to get pregnant again following surgery than women who had not, and that increasing age reduced the likelihood of becoming pregnant.

Results of the study, conducted by researchers at UB, appear in the August issue of the Journal of the American Association of Gynecologic Laparo-scopists.

Ronald E. Batt, clinical professor of gynecology and obstetrics and principal author of the study, said the pain relief was particularly important because it was long-lasting.

"Three years after surgery, the pain relief holds," Batt said. "Seventy-five to 80 percent of women were very happy with the result. Surgery appears to be a good way of treating endometriosis for both health and fertility."

Major cause of infertility

Endometriosis is a condition in which fragments of the uterine lining, the endometrium, migrate and adhere to other sites in the pelvic cavity, including the ovaries, bowel, bladder and ureters. It affects women of reproductive age and is a major cause of infertility. Symptoms include pelvic pain, abnormal bleeding and painful sexual intercourse.

In addition to evaluating the health and fertility outcomes of patients treated surgically for endometriosis, the purpose of the study was to identify significant predictors of pregnancy following surgery. The subjects were 290 women diagnosed with endometriosis between November 1986 and March 1988 at a community-based gynecologic practice and treated surgically, either via laparoscopy, or laparotomy (open abdominal surgery) following laparoscopy and drug treatment.

Health and reproductive histories were taken when the women enrolled, and medical and surgical records were abstracted for pertinent information on disease status. Participants also were asked to define the severity of their symptoms and infertility problems. Seventy-one percent of the patients in the study had come to the practice because of infertility.

Three years following treatment, patients completed questionnaires requesting information on changes in endometriosis symptoms, pregnancy history and factors that can affect the chances of conception, such as the number of months attempting pregnancy, special reproductive technologies, cigarette smoking, alcohol and caffeine consumption, stress and exercise.

Of the 232 patients who completed the questionnaires, the majority reported "some" or "great" improvement for the following symptoms:

- Painful intercourse-46 percent reported "great" improvement; 33 percent "some" improvement

- Pelvic pain-43 percent reported "great" improvement; 32 percent "some" improvement

- Abnormal menstrual cycles-31 percent reported "great" improvement; 42 percent "some" improvement

- Heavy bleeding-28 percent reported "great" improvement; 40 percent "some" improvement.

At the three-year follow-up report, 53 percent of the women reported one or more pregnancies. Approximately two-thirds of pregnancies resulted in live births. The percentages increased slightly when results were restricted to women who had said before surgery that they wanted to become pregnant. Of this group, 61 percent reported one or more pregnancies and 69 percent of these pregnancies resulted in a live birth, Batt said.

Advancing age a factor

Women who had given birth at least once prior to surgery and those with no gynecologic problems other than endometriosis had the best chance of giving birth following surgery, results showed.

Advancing age significantly decreased the likelihood of a live birth, even after all other factors were considered, as well as reducing the chances of becoming pregnant.

One unexplained outcome of the study was the preponderance of baby girls. In the general population, boy babies generally hold a slight edge. In this study, first pregnancies following surgery resulted in 36 boys and 39 girls; second pregnancies-17 boys and 23 girls, and third pregnancies-three boys and six girls.

"We don't have an explanation for it," Batt said. "We have observed this endometriosis-related phenomenon for years. I suspect it is one of the effects of the disease process: Selectively, there are more female fetuses that survive."

Additional researchers were Germaine Buck, UB associate professor of social and preventive medicine, and Richard A. Smith of Tufts University School of Medicine.