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What exactly is RELAXIN?

Relaxin is another key pregnancy hormone. Let’s look at what it is, what it does, and discomforts it may cause (because you know there are going to be a few).

Introduced into the body by the ovaries, relaxin levels increase right after ovulation. If pregnancy occurs during a particular cycle, relaxin levels rise. If not, the levels drop off again. During pregnancy relaxin is also released from the placenta, the chorion membranes, and the lining of the uterus (the endometrium).

How Does Relaxin Promote a Healthy Pregnancy?

During pregnancy, relaxin sends many signals to a woman’s body. For example, it

  • Promotes the implantation of the embryo.

  • Stops the uterus from contracting (to prevent premature childbirth).

  • Encourages the growth of the placenta.

  • Regulates cardiovascular and renal systems, specifically the heart and kidneys, as they adjust to support the baby.

  • Relaxes blood vessels to increase blood flow to the placenta and kidneys. (Blood volume can increase by 50% during pregnancy, so this is important!)

  • Helps rupture the membranes at the beginning of labor.

  • Opens and softens the cervix and vagina in preparation for childbirth.

  • Relaxes the pelvic ligaments at delivery.

Discomforts Caused by Relaxin

As we have talked about before with other hormones, while doing all this good, relaxin also causes some of our least-favorite pregnancy discomforts.

#1 Constipation

#2 Indigestion

#3 Aches as your ligaments, bones, and muscle loosen closer to delivery

#4 Shifts the center of gravity making you feel a little unsteady on your feet

#5 Pelvic pain

Be Prepared

It is so helpful to know what to expect throughout the weeks and months of pregnancy. Tennessee Family Doulas’ Childbirth Education class answers your questions (especially, “Is this normal?”) and prepares you to make the decisions that are best for you during labor, delivery, and the early days at home. We would love to hear from you and walk with you on this amazing journey!


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