A major cause of infertility related to structural abnormalities of the female reproductive tract is?

A. endocrine disruptors
B. pelvic inflammatory disease
C. obesity
D. diabetes

Approximately 50,000 women become infertile in the US each year from PID . N. gonorrhoea is isolated in only 40-60% of women with acute salpingitis (Current OBGYN 9th ed 2003). C. trachomatis was estimated by current obgyn 9th ed to be the cause in about 60% of cases of salpingitis, which may lead to PID.
Answer is B.

Pelvic inflammatory disease (PID) is the major cause of female infertility worldwide. PID comprises a variety of infections caused by different bacteria that affect the reproductive organs, appendix, and parts of the intestine that lie in the pelvic area. The sites of infection most often implicated in infertility are in the fallopian tubes, a specific condition referred to as salpingitis .

PID may result from many different conditions that cause infections. Among them are:

Sexually transmitted diseases (cause of most PIDs). Chlamydia trachomatis is an infectious organism that causes 75% of infertility in the fallopian tubes. Gonorrhea is responsible for most of the remaining cases.
Pelvic tuberculosis (a growing global problem as tuberculosis cases increase)
Nonsterile abortions
Ruptured appendix
Herpesvirus (suggested for some cases, but not confirmed as a cause).
Symptoms of PID. The infection may be subclinical (occurring without any symptoms), or there may be fever, chills, or pelvic pain indicating inflammation of the entire pelvic area.

Effects of PID. Severe or frequent attacks of PID can eventually cause scarring, abscess formation, and tubal damage that result in infertility. About 20% of women who develop symptomatic PID become infertile. PID also significantly increases the risk of ectopic pregnancy (fertilization in the fallopian tubes). The severity of the infection, not the number of the infections, appears to pose the greater risk for infertility.
The answer is B: