You'll undergo numerous body changes during pregnancy. Physical changes, emotional changes and hormonal changes are all taking place as the pregnancy progresses. In fact, hormonal changes are responsible for many of the physical changes and emotional changes that take place.

The following are hormones produced by the placenta:

• Gonadotropin-releasing hormone
• Corticotropin-releasing hormone
• Urocortin
• Somatostatin
• Growth hormone-releasing hormone
• Ghrelin
• Thyrotropin-releasing hormone
• Dopamine
• Neuropeptide Y
• Enkephalin
• Pituitary analogues
• Chorionic gonadotropin
• Placental lactogen
• Chorionic corticotropin
• β-Endorphin
• α-Melanocyte-stimulating hormone
• Placental variant growth hormone
• Oxytocin
• Steroid hormones
• Estrogens
• Progesterone
• Other
• Activins

Human chorionic gonadotropin (hCG)

Human chorionic gonadotropin, or hCG, is a hormone secreted by the placenta that maintains pregnancy during the early development of the embryo. Many of the symptoms that women experience in early pregnancy, such as morning sickness and fatigue, are caused by rising levels of hCG within the body.

Estrogen

Estrogen, a hormone that is produced by the ovaries and placenta, also increases during pregnancy. The hormone regulates progesterone levels during pregnancy, which is critical to a healthy pregnancy. Estrogen is responsible for the continued growth of fetal lungs, kidneys, and reproductive organs as well as the placenta. Estrogen also aids in the development of prolactin, which enables lactation after delivery.

Progesterone

Progesterone, a hormone that is produced by the ovaries and placenta, prepares the uterus for the implantation of a fertilized ovum. Because this hormone restricts the uterus from contracting during pregnancy, fights off hazardous cells that could harm the fetus, and aids in maintaining the pregnancy, progesterone is crucial to a healthy pregnancy.

Just like hCG, progesterone levels will increase as pregnancy progresses. Progesterone is the hormone that causes breast tenderness in the early weeks of pregnancy, as well as constipation, headaches, food cravings, and mood swings throughout pregnancy.

Emotional changes

Because of the rising levels of hormones within a woman’s body during pregnancy, emotional changes should be expected. A wide variety of emotions can be expected, ranging from excitement and anticipation to worry and fear.

Physical changes

Physical changes during pregnancy can also be brought on by increasing hormones. Many women will notice skin changes as pregnancy progresses. Darkening of the skin, red patches, pregnancy glow, and oily skin can all be caused by rising hormone levels.

Just as hormones drastically increase during pregnancy, these same hormones will rapidly decrease after delivery, potentially causing the baby blues or postpartum depression. Knowing how to cope with the changes in hormone levels and when to contact your healthcare provider is very important.

Temperature changes

With pregnancy comes an increase in the metabolic rate resulting in greater heat production. The greater metabolic rate also calls for a higher need for energy or higher food consumption.

The fetus' metabolic rate generates additional heat; the fetus is thus at a temperature of 0.5 to 1.0 ºC (0.9 to 1.8 ºF) above the mother’s levels. The mother’s temperature decreases 0.3 ºC (0.5 ºF) in the first trimester and decreases 0.1 ºC (0.2 ºF) per month through gestation helping to prevent a mother’s core temperature from rising with the increased metabolic rate. The physiologic changes (increased skin blood flow) occurring during pregnancy help to reduce maternal body temperature.

With this increase in the resting metabolic rate of women during pregnancy there comes an increased need for energy to allow for proper growth of the fetus throughout term; after the 13th week of pregnancy roughly 300 calories extra are needed per day to meet the needs of pregnancy.

Additionally, with the increased resting body temperature of the mother caused by the fetus, it is important to exercise in a well ventilated or air-conditioned area. It might be in the interest of the mother to place a fan in the room during exercise to provide for extra air circulation; exercising outside during the hottest part of the day should also be avoided. With the increased temperature, it is crucial to the mother stays hydrated throughout gestation. This means consuming water throughout the day and not using thirst as a sign to drink fluids; thirst is a sign you are already dehydrated! Also remember caffeine (cokes and coffee), is a diuretic and should be avoided.