A 4-cm cyst in the left adnexa is usually possible to get pregnant, as long as the right adnexa ovary and fallopian tube as well as the uterus are normal.
The mechanism of pregnancy is that the egg and sperm meet in the fallopian tube and form a fertilized egg, which is then transported to the uterus and deposited in the uterus under the action of the fallopian tube cilia. If the organs involved in this process are normal, pregnancy is generally not affected, and a 4cm cyst in the left adnexa does not affect the function of the right adnexa.
Left adnexal cysts may be physiological, may exist for a period of time, will disappear automatically, generally do not need treatment; may be pathological, if the growth is more than 5cm or pain, menstrual abnormalities and other symptoms, then need to be treated, if necessary, can be operated.
In clinical practice, if there is a 4cm cyst in the left adnexa, ultrasound examination should be conducted regularly for monitoring, and if there is any abnormality, timely medical treatment should be sought.