What is the cause of myometrial contraction in second trimester pregnancy?

The main cause of myometrial contraction in the second trimester of pregnancy is the increased production of oxytocin by the placenta and the increased sensitivity of the myometrium to oxytocin.

Other factors that can contribute to myometrial contractions in the second trimester include:

* Progesterone withdrawal: As the levels of progesterone decrease in the second trimester, the myometrium becomes more sensitive to oxytocin.

* Increased estrogen levels: Estrogen can stimulate the production of oxytocin and increase the sensitivity of the myometrium to oxytocin.

* Stretching of the uterus: As the uterus grows and stretches, it can trigger myometrial contractions.

* Physical activity: Physical activity can increase the production of oxytocin and trigger myometrial contractions.

* Emotional stress: Emotional stress can increase the production of oxytocin and trigger myometrial contractions.

Myometrial contractions in the second trimester are usually mild and infrequent. However, in some cases, they can be more severe and may be associated with preterm labor. If you are experiencing any concerns about your myometrial contractions, it is important to talk to your doctor.