The risk of adverse health outcomes from multiple sex partners is greater for females than males, as it has direct influence on reproductive health. Untreated STDs may make females susceptible to cervical dysplasia (abnormal cells on the surface of the cervix) and pelvic inflammatory disease (PID), which can lead to infertility, ectopic (tubal) pregnancies (EP), and compromised fetal health.
Pelvic inflammatory disease (PID), a complication of chlamydia and gonorrhoea, is associated with female tubal infertility. PID can cause scarring and damage which can affect fertility. If both or one of the fallopian tubes are blocked due to scars and adhesions, then the sperm will not reach egg and egg cannot make way to the uterus. This prevents fertilization and also pregnancy. If only one fallopian tube in blocked, there is yet a possibility that a woman can get pregnant, since the other tube can release an egg and let a sperm swim through. Two blocked fallopian tubes, however, are not a good sign for women who wish to naturally become pregnant. Untreated PID can result in long term complications including ectopic pregnancy and infertility.
Surgical treatment for EP includes salpingectomy (surgical removal of a fallopian tube), salpingostomy (creation of an opening into the fallopian tube, but the tube itself is not removed) and tubal anastomosis (unblocking of the fallopian tubes).
Tubal anastomosis restores patency of the fallopian tubes after sterilisation, in patients who wish to become pregnant. First, a tubal surgery scar after tubal anastomosis can easily cause stenosis and tubal blockage, which interferes with sperm fertilisation of eggs in the fallopian tube, resulting in blastocyst (early developmental structure) formation in the fallopian tube. Thus, there would be a lower intrauterine pregnancy rate and higher recurrence of EP after tubal anastomosis. Second, other potential risk factors may produce these results. In summary, the mechanisms of lower intrauterine pregnancy rate and higher EP recurrence after tubal anastomosis are still unclear and further study is needed.
Adolescent girls who have multiple partners may also be vulnerable to dating violence.
In addition to any physical effect, the psychological effect of having an STI may also have an adverse impact on both male sexual function and fertility and therefore should not be overlooked. Specifically, psychological stress is common in patients with prostatitis (inflammation of prostate). 43% of men with symptomatic prostatitis complain of erectile dysfunction and 24% report low libido, thus adversely affecting the ability to conceive.