Throughout pregnancy, and during the postpartum period, hormones will continue to fluctuate (actually, throughout a woman's lifetime hormones will fluctuate). Today though we are going to focus on the breastfeeding period. During a mother’s time breastfeeding, estrogen levels remain lowered to let the hormones such as prolactin and oxytocin, that assist in breastfeeding, do their jobs. Estrogen itself has over 400 roles in the body, one of which is to help in bone health and muscle strength and function. So does low estrogen mean that we will have more pelvic floor dysfunction or that we should avoid activity? And does increased activity mean we will see a dip in our milk supply?
Based on the above statement, the answer would appear to be yes, however, there is some good research that can hopefully dispel some fears for my fellow breastfeeding mamas. A study done in 2020 looked at women that had reported pelvic floor dysfunction during pregnancy. They followed up with them initially at the postpartum mark as well as 3 months postpartum and there was no difference in the breastfeeding and non breastfeeding group in regards to their symptoms. Overall conclusion was that ‘’women with PFD (pelvic floor dysfunction) symptoms prior to or during pregnancy can be reassured that breastfeeding probably does not delay the pelvic floor floor recovery.” (1) An additional study found that “breastfeeding after vaginal childbirth was not associated with the development of stress urinary incontinence, pelvic organ prolpase, or anal incontinence 1-2 decades after the first vaginal delivery” (2). Also great news! To be fair, there were a handful of studies that did show a possible link but usually breastfeeding was listed along with many other factors. For example a study done in 2003, found that postpartum incontinence could be associated with length of breastfeeding but also BMI, frequency of urination, incontinence during pregnancy, use of forceps, smoking, and vaginal delivery (3)
Now to our next question. Does exercise decrease your milk supply? A review of the research (thanks Kelly Mom!) shows that moderate exercise has no effect on milk supply or milk composition. Exercising to exhaustion however may have a short term effect on composition with a decrease in IgA (immunoglobulin –important for immune function) and an increase in lactic acid buildup. Because most women are not exercising to exhaustion frequently there are really no harmful effects known for baby. (4)
So what does this all mean? Ultimately it means that research shows that a gradual return to sport and activity level can be safe for your pelvic floor while also allowing you to breastfeed . What I would STRONGLY encourage individuals to do is to touch base with a pelvic floor physical therapist before ramping up your exercise routine, especially if you are having any symptoms (this can include anything from incontinence, pelvic pain, constipation, low back pain, etc).