Progesterone plays a vital role in pregnancy, especially in preparing the body for labor. It is a hormone produced mainly by the ovaries and later by the placenta during pregnancy. This hormone helps maintain the uterine lining, ensuring the baby grows in a stable environment. It also prevents the uterus from contracting too early, which could lead to premature labor. As pregnancy progresses, its levels rise, keeping the uterus relaxed and preventing contractions until the body is ready for labor.
Progesterone also supports the development of the mammary glands. These glands prepare the body for breastfeeding after birth. Another key function is to suppress the maternal immune system. This prevents the body from attacking the developing fetus, which it might otherwise recognize as foreign.
By the third trimester, the balance between progesterone and other hormones begins to shift, preparing the body for delivery.
Progesterone and Labor Onset
As labor approaches, progesterone levels drop, allowing other hormones, like oxytocin and prostaglandins, to take over. These hormones trigger contractions and signal the body that it’s time for delivery. This decrease relaxes the cervix and promotes its softening and thinning, also known as effacement.
Progesterone’s decrease also helps the body prepare for labor by increasing uterine sensitivity to oxytocin. Oxytocin is the hormone responsible for strong, coordinated contractions. As these contractions increase, the cervix dilates, and labor begins.
Some pregnancies may experience complications due to low progesterone. In these cases, it supplements may be prescribed to prevent premature labor or miscarriage. These supplements can help keep progesterone levels stable until the baby is ready for birth. However, they are generally discontinued closer to full term to allow labor to proceed naturally.
Understanding its role in pregnancy helps explain the body’s complex processes leading to labor. Proper progesterone levels are essential for a healthy pregnancy and a timely labor.