Hormones, chemical messengers released by glands into the bloodstream, regulate a wide variety of physiological functions, and during pregnancy hormones affect not only the mother but also the child. Estrogen and testosterone play an instrumental role in determining sexual characteristics, behaviors and functions. While you’re pregnant, your doctor will monitor the levels of these two hormones because they can indicate possible issues, including risk of miscarriage, birth date estimates and progress of the pregnancy.
Estrogen, produced and released primarily by the ovaries, refers to the female hormones of estradiol, estrone and estriol. Estrogen triggers the development of females’ secondary sexual characteristics, such as breasts, regulates menstruation and helps to maintain bone, cardiac and endocrine health. Estrogen participates in the synthesis of proteins, regulation of fluid balance, increase of fat stores, reductions of muscle mass and formation of bones.
Estrogen in Pregnancy
Estrogen levels vary day to day, but certain hormonal triggers cause spikes in estrogen levels. Estradiol levels can increase eight-fold during ovulation. During pregnancy, estradiol is produced by the placenta, and estrogen levels can increase by a factor of 100. The estrogen helps to maintain the pregnancy, but it also may have other effects as well. Short-term physical effects of high estrogen can include cramps, headaches, weight gain and fatigue.
Estrogen and Emotions
The woman who is going through a pregnancy is dealing with life-altering issues. The increase in estrogen, as well as other hormone changes during pregnancy can contribute to her emotional instability. Emotional effects of increased estrogen can include depression, anxiety, panic attacks, low esteem and mood swings. After delivery, hormone levels, including estrogen, change dramatically again. The sudden drop in estrogen may contribute to postpartum adjustment issues such as depression and fatigue. Antidepressants and low-dose hormone replacement treatments may help during postpartum recovery.
Testosterone in Women
Though testosterone is considered a male hormone, a small amount of testosterone is produced by the ovaries and the adrenal cortex. During puberty, testosterone triggers the release of estrogen, which promotes the development of body hair, breasts, and triggers menstruation. Testosterone also contributes to muscle development and sex drive.
Testosterone in Pregnancy
While testosterone levels vary for different women, testosterone is usually produced at low levels during pregnancy. However, women can be exposed to testosterone through medications to increase sexual drive or though inadvertent contact with topical testosterone creams. Androgen use, especially during the first trimester of pregnancy, can cause masculinization of the external genital of the female fetus. In other words, the female fetus develops a scrotum and penis. Testosterone should not be used during pregnancy.
Research on the effects of natural differences among women's testosterone levels during pregnancy suggests several effects. Maternal testosterone levels during pregnancy are associated with smaller offspring size at birth, reports a 2006 study published in the “European Congress of Endocrinology.” Also, both boys and girls who were exposed to higher levels of testosterone in utero had more male-typical behavior as children, according to a 2009 study published in "Psychological Science." Girls in particular were sensitive to their mother’s testosterone level. Pregnant women who have higher testosterone levels produce girls who engage in more tomboy-like behavior, reports a 2002 study published in “Child Development.”