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  • Writer's pictureANH Team

Let's Talk Relaxin: What Is It?

Updated: Nov 1, 2023

As the name suggests, Relaxin is a hormone that aids in "relaxing" the body of a pregnant woman in the final stages of pregnancy in order to prepare for delivery.

Additionally, it's an important hormone for reproduction. To prepare your uterus for a potential pregnancy, Relaxin levels rise after ovulation. This hormone will decline if conception doesn't occur, otherwise, your levels will increase to support a viable pregnancy.

What is Relaxin?

Relaxin is a hormone that is produced during pregnancy to allow our bodies to stretch and grow as the baby develops through gestation. It also plays an important role in the labor process as well as delivery through the birth canal. Many people associate this hormone with the aches and pains that come with pregnancy, such as low back pain, pubic bone pain or sciatica. However, Relaxin actually affects all the ligaments, muscles and joints in our bodies. Relaxin levels are at their highest during early pregnancy. It works by stimulating the growth of the placenta and aids in promoting the implantation of the embryo into the uterine wall during the first trimester.

How is the Relaxin hormone produced?

Your menstrual cycle is actually broken down into two phases, follicular and luteal, and your hormones are hard at work during both of them to prepare for a pregnancy. The follicular period is when your body releases hormones that encourage egg growth and development on the ovaries. Ovulation is the release of a mature egg by the ovary in the hopes that it will be fertilized. The luteal phase begins the day ovulation occurs and lasts until your next period begins. The ovary releases an egg, leaving behind an empty follicle called the corpus luteum. Progesterone, which coupled with relaxin thickens your uterine lining to aid in implantation of the fertilized egg, starts to be released by the corpus luteum.

It begins first by your ovaries and continues to rise during the second half of your menstrual cycle in anticipation for possible pregnancy. If you become pregnant, Relaxin will then be produced by the placenta. This hormone will increase until it plateaus at the end of the first trimester and remains at that level throughout. Women generally begin to experience musculoskeletal discomfort around the beginning of the second trimester. There is a surge of relaxin production in the third trimester that is thought to help with the labor process as well.

Does Relaxin cause any symptoms to occur during pregnancy?

Although it's unlikely that relaxin will have any serious negative effects on you, some women do experience discomfort as a result of the hormone's effects on their bodies. Symphysis pubis dysfunction, or extreme pelvic pain, affects 1 in 300 pregnancies, according to estimates. This is why seeing a Webster certified chiropractor who adjusts most of these areas is so helpful for pain during pregnancy!

Relaxin can cause pelvic girdle pain and some experience discomfort in a variety of places:

  • Pubic bone

  • Sciatic joints

  • Lumbar spine

  • Hips / radiating pain along the gluteal muscles

  • Inner thighs

  • Perineum

Relaxin can affect all of the joints in the body during pregnancy and a variety of musculoskeletal complaints:

  • Abdominal pain

  • Low back pain/ instability in the core

  • Carpal tunnel syndrome

  • Foot pain due to loss of arch support

  • Hip/ knee/ ankle pain

  • Neck pain / tightness

What's the purpose of Relaxin besides preparing our bodies for birth?

Relaxin helps with the implantation of the embryo in the uterus as well as prevents uterine contractions during implantation as well as in early pregnancy. It helps to promote the growth of the placenta and the muscle/ ligament laxity helps to prevent early contractions. Relaxin is an incredibly important hormone throughout pregnancy but there are some research studies showing that it may have other functions as well.

Relaxin has not been highly studied in the medical community either. Research assumes that Relaxin is produced in the ovaries by direction from the Luteinizing Hormone released by the pituitary gland, as well as the human gonadotropic hormone during pregnancy. However, even that research is not proven. The levels have not been highly studied but there is research showing that low levels of relaxin are associated with endometriosis.

Does the Relaxin hormone assist our bodies apart from pregnancy?

Current research is showing a correlation with low relaxin and the autoimmune disorder scleroderma as well. Data with less substance also associated relaxin with constipation, bloating and indigestion that can be associated with pregnancy due to the intestines not being as tight as they normally are. Relaxin relaxes the arteries and vessels contributing to blood pressure. It has been thought to be anti-inflammatory and helps with scar tissue/ adhesion. Relaxin can also weaken your pelvic floor musculature.

How can we help mediate the effects of Relaxin?

Webster Certified chiropractors are specially trained to adjust 6 major regions- sacroiliac joints, piriformis muscle, sacrotuberous ligaments, psoas muscle, round ligaments and pubic bone. The treatment of these regions can significantly reduce a patient’s pain levels throughout pregnancy. Adjustments are performed very gently due to the laxity that is present and many patients see immediate relief within 1-2 visits. Another great resource is seeing a pelvic floor physical therapist prior to birth! They can help with pelvic floor musculature and give tips and tricks to help prepare for labor as well! They are also an incredibly important resource to use after birth; we think pelvic floor PT should be standard for all women after giving birth!

A really interesting point to note is that Relaxin can actually remain in your body for up to 12 months postpartum and even longer if you breastfeed. It decreases to a lower level after birth but then remains for quite a while. This means that getting adjusted after birth is so important to ensure that the joints are functioning properly in order to prevent long term pain or tension within certain regions.

By: Dr. Abby Kellogg

Chiropractor at ANH Wellness

Disclaimer: "The information including but not limited to text, graphics, images, and other material contained on this website is for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment."

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