Pregnancy is apt to turn any formerly sane and seemingly competent women into a rather unpredictable creature; and with good reason! The culprits, it seems, are our hormones.
The Role of hCG and Early Pregnancy Symptoms
The first hormone to make its appearance after conception is human chorionic gonadotropin (hCG), also called “the announcer of pregnancy,” as it is hCG that’s picked up by a urine or blood test to determine pregnancy.
In a normal pregnancy, the level of hCG approximately doubles about every two days during the first 10 weeks. HCG keeps the pregnancy hormones known as estrogen and progesterone at their appropriate levels until the placenta has developed enough to take over this function.
If you are pregnant, you’ve probably already noticed a side effect of hCG—a sensitive bladder. HCG is responsible for increasing the blood supply to your pelvis, which, in turn, makes your bladder want to get rid of the tiniest amount of urine. The good news is that this condition generally eases after the first trimester (although it will return later as baby gets bigger and starts pushing on your bladder).
HCG is thought to be responsible for numerous other symptoms associated with early pregnancy, including nausea and the sometimes resultant vomiting. These symptoms are commonly referred to as morning sickness, although the term is misleading because the queasiness involved can occur at any time, day or night. Morning sickness tends to peak around the eighth to tenth week of pregnancy when hormone levels are highest and should then taper off as the second trimester begins.
Estrogen and Progesterone
Although doctors have conflicting ideas on which hormones cause what, it seems certain that the two hormones that play a major role in pregnancy are estrogen and progesterone. These hormones are responsible for the bulk of pregnancy symptoms experienced by expectant women.
- Breast soreness and sensitivity, for example, are caused by increasing levels of these hormones and should diminish significantly after the first trimester.
- Another area of sensitivity is your sense of smell, also thought to be a side effect of rapidly increasing hormones. It’s not uncommon to be overwhelmed by certain smells that you liked before, or to find that certain foods are now repulsive to you.
- Fatigue is a side effect of progesterone, which has the same effect on the brain as some sleeping tablets! This is why drowsiness, and even complete exhaustion at times, occurs. But energy levels generally return once you enter the second trimester.
- One function of progesterone is to inhibit the smooth muscle in the uterus from contracting, thus allowing the fetus to grow with the expanding uterus. However, the hormone is not selective. As progesterone levels increase, other smooth muscles in the body may be affected, such as the lower esophageal sphincter whose shifted gear functioning may result in increased heartburn and acid reflux, especially in the later stages of pregnancy.
- The bowel muscles also relax, and since the bowel contains gas, the muscle tone decrease causes bowel distention. A bloated feeling is thus very common in pregnancy.
- Progesterone also softens cartilage, so it may be responsible for the hip and pubic bone pain that often accompany pregnancy.
Hormones and Emotional Fluctuations
While these physical symptoms are obvious, there are other effects of pregnancy hormones, which are just as important to recognize. St. Louis psychologist Dr. Diane Sanford, PhD, says that significant changes in your hormones can affect your levels of neurotransmitters, the brain chemicals that regulate mood.
You’re most likely to experience these changes at around six to 10 weeks, and then again in the third trimester as your body prepares for labor and delivery. All women respond differently, so you can expect to feel anything from mood swings to depression or states of anxiety.
An increased circulating level of these pregnancy hormones is also partly responsible for the magnification of the complex emotions, which you, as a pregnant woman, already have to deal with. The joy of simply being pregnant may be enough to move you to tears. Anxiety regarding how you feel about yourself and the way your body is changing is normal, as are concerns about your health and the health of your developing fetus.
However, overreaction to these, and even simple issues, can be problematic. You may frequently become tearful and find it difficult, or even impossible, to give a reason for your behavior. Recognize that this can be unsettling for your husband too, possibly causing him feelings of confusion and inadequacy. If he feels unable to handle your tears, he may withdraw and ignore the problem, which you may perceive as unloving and non-supportive. Understanding that your behavior is normal will make it far easier for your partner to accept, and may help him be more supportive.
Although your mood swings will be a source of stress to some extent throughout your pregnancy, there’s no need for you to suffer increased anxiety over them. Being an expectant mother brings enough to worry about without having to psychoanalyze your ups and downs. Just blame it on the hormones!