Birth Terminology Explained: Relaxin

There is a lot of terminology thrown around when you enter the world of pregnancy, birth, postpartum, baby feeding, and early parenthood. In our "Terminology Explained" series, we help you break it down, bit by jargony bit. 

The term for today is relaxin. 

What is Relaxin? 

Official Definition: Relaxin is the hormone responsible for relaxing your body late in pregnancy as it prepares for childbirth. This doesn't necessarily mean you feel relaxed, but rather, relaxin helps loosen the ligaments, joints, and muscles in your pelvis to make the process of birth easier. When it comes to getting ready for birth, relaxin is essential! 

Relaxin also plays critical roles during early conception and in early pregnancy. In fact, relaxin is highest during early pregnancy to help the embryo with implantation into the uterine wall, promote growth of the placenta, and prevent uterine contractions that would otherwise cause early childbirth.  

When you will hear/see the term used? You might learn about relaxin while reading books about pregnancy and birth, in a childbirth class, or in discussions with your care provider. Since relaxin is also responsible for some unpleasant side effects like constipation and upset stomach in early pregnancy, and feeling unsteady/off balance and experiencing pelvic, back or hip pain later in pregnancy, you may discover learn about the hormone after searching up its symptoms.  

Why is it important/beneficial? Relaxin is just one of many vital hormones responsible for a healthy reproductive process. In addition to the roles described above, it's also responsible for helping prepare your own organs for the extra demands of pregnancy, including increased blood volume.