Is It Possible To Become Pregnant After A Tubal Ligation?
Yes, it is possible to become pregnant after a tubal ligation but the chances are very small. The risk of subsequent pregnancy is between 1 in 200 to 7 in 1000 women. If pregnancy does occur there is an increased chance that it will be an ectopic.
You can consider either a home pregnancy test or blood test for HCG which would have to be done by your doctor.
It is possible that the irregular menstrual cycle is related to other factors such as: (1) menopause, this can also be done via blood tests checking for specific hormones (2) abnormal levels of thyroid hormone (3) emotional or physical stress (4) excess physical activity (5) high levels of a hormone called prolactin which is secreted in the brain , this level can be checked by blood tests as well.
You may want to consider, if possible, visiting your doctor who can do a panel of bloods including HCG, reproductive hormones (to check re possibility of menopause), thyroid hormone and prolactin.
I hope this helps, feel free to ask any other questions