Relaxin is a hormone primarily associated with pregnancy, playing a significant role in preparing the female body for childbirth. Its name reflects its general purpose: to relax and loosen certain tissues. This hormone helps facilitate the physical changes that occur during pregnancy and as the body adapts for delivery.
Relaxin’s Journey During Pregnancy
During pregnancy, relaxin is produced by the corpus luteum in the ovary and later by the placenta, the membranes surrounding the fetus, and the lining of the uterus. If pregnancy occurs, its production increases significantly.
Relaxin’s functions throughout pregnancy are diverse, including softening ligaments and joints in the pelvis to allow for expansion and easing the passage of the baby through the birth canal. It also helps relax uterine muscles, which prevents early contractions, and promotes cervical ripening as labor approaches. Relaxin levels begin to rise shortly after conception and reach their peak around 12 to 14 weeks of pregnancy. After this initial peak, levels decline but remain elevated throughout the rest of pregnancy, with some sources suggesting another surge just before delivery.
The Decline of Relaxin Postpartum
Relaxin levels drop significantly after childbirth, primarily because the placenta, a major source of the hormone, is expelled from the body. This rapid decrease begins shortly after delivery. The hormone then continues to decline over the following weeks and months.
While the immediate drop is swift, relaxin levels do not return to pre-pregnancy levels instantly. It can take several months for the hormone to normalize, a timeframe of five to twelve months. The exact timing can vary between individuals, and for those who are breastfeeding, relaxin levels may remain elevated for a longer period. This extended presence allows for continued flexibility in the body, which can be beneficial for recovery.
Lingering Effects and Recovery
Even after relaxin levels have returned to their normal, pre-pregnancy state, its effects on the body, particularly on joints and ligaments, can linger. This occurs because the physical changes induced by the hormone, such as stretched ligaments, take time to regain their original tension and stability.
Recovery can extend over several months, typically taking anywhere from three to six months, or even up to a year, for the body to fully stabilize and for joint laxity to resolve. New mothers might experience sensations like generalized joint pain, instability, or a feeling of looseness, especially in the hips, pelvis, and knees. This prolonged recovery period underscores the importance of a gradual return to physical activity and being mindful of the body’s altered state postpartum.