progesterone during pregnancy
Progesterone Production During Pregnancy and the Placenta
The placenta is the tissue that is created to connect the mother and baby. About a week after conception, the placenta begins to secrete the hormone human chorionic gonadotrophin (hCG).
This hormone prolongs the lifespan of the corpus luteum as well as stimulates production of progesterone. The placenta continues to produce both progesterone and estrogen for the duration of the pregnancy and the levels get higher and higher right up to just before the birth.
Placenta
The tissue that connects the embryo to the inner surface of the uterus. The baby is attached to the placenta by the umbilical cord. Exchange of gases, nutrients and fluids between the mother and embryo takes place through the placenta. It is expelled from the uterus after the baby is born. Also called 'afterbirth'.
During the pregnancy, the progesterone is needed in the following ways, (mostly in conjunction with estrogen):
- Makes the endometrium develop and secrete fluids after being primed by estrogen.
- Maintains the functions of the placenta and fights off unwanted cells near the womb that could cause damage to the placenta or baby.
- Keeps the endometrium in a thickened condition.
- Stops the uterus making spontaneous movements.
- Stimulates breast tissue growth.
- Prevents lactation until after the birth (with estrogen).
- Strengthens the mucus plug covering the cervix to prevent infection.
- Strengthens the pelvic walls in preparation for labor.
- Stops the uterus from contracting (thus keeping the baby where it is).
At the end of the pregnancy, the levels of progesterone secreted by the placenta during pregnancy drop off. It is this action that stimulates the beginning of the contractions that will lead to birth.
A minimum level of about 10ng/ml is required to sustain a pregnancy through the very early stages. It is because of this that doctors can measure the levels of progesterone in the blood to assist in the diagnosis of abnormal pregnancies such as ectopic pregnancy.
Progesterone Supplements During Pregnancy
Supplements of natural progesterone cream are sometimes prescribed as a fertility treatment or to assist in reducing the risk of miscarriage. This is found in the form of a cream that is rubbed into the abdomen and thighs or else it arrives as a vaginal suppository or an injection (tablets don't work very well).