You are a columnist for a popular website that deals with women\'s health issues

Question

You are a columnist for a popular website that deals with women's health issues. Visitors to the site can submit their stories and questions through an “Ask the Expert” link on the site. In this scenario, a 26-year-old woman has posted her story and some questions regarding reproductive health. My name is Angela. I am a 26-year-old married woman with no children. My husband, Doug, and I have been trying to get pregnant for over two years now and my doctor has suggested that I consider fertility drug treatments. The irony of our situation is that I have been taking a birth control pill for five years to prevent getting pregnant, and now my doctor suggests that I take another drug to help me get pregnant. When I went off birth control, about a year ago, my menstrual cycle became very irregular. I had been taking a birth control drug called Ortho Tri-Cyclen. To be perfectly honest, I don't understand how it works because my periods were more regular when I was on the pill than when I went off of it. My doctor told me that the pill works because it tricks your body into thinking that it is pregnant. That just confused me even more. When I looked back on my decision to take birth control pills, I realized that I did not really understand how they work. I just do not want to make that mistake again. Before I consider taking any more drugs, I want to understand more about how they work. The drug we’re looking into is called Clomid. I asked my doctor a bunch of questions, but I still feel confused. I looked up some stuff online when I got home. Here is some information that I learned from a website about how Ortho Tri-Cyclen works: Estrogen and progestin work in combination to suppress the hypothalamic-pituitary-gonadal (HPG) axis. This suppression leads to a decrease in the release of gonadotropin-releasing hormone (GnRH) from the hypothalamus and luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary. Maturation of the dominant follicle is inhibited under the decreasing levels of FSH and LH. Hormonal contraceptive use also leads to an increase in the viscosity of the cervical mucus, which inhibits sperm penetration and movement through the cervical canal. I am hoping that you would be able to help me understand how these drugs actually work. My doctor told me that birth control pills contain small amounts of estrogen and progesterone, and these hormones prevent me from ovulating. I don’t understand how giving me these hormones in a pill would prevent me from ovulating. I assume that it has something to do with the levels of the gonadotropins that I asked about earlier. Can you explain this to me?

Explanation / Answer

Gonadotrophin-releasing hormone is produced and secreted by specialised nerve cells in the hypothalamus of the brain. It is released into tiny blood vessels that carry this hormone from the brain to the pituitary gland where it stimulates the production of two more hormones – follicle stimulating hormone and luteinising hormone. These hormones are released into the general circulation and act on the testes and ovaries to initiate and maintain their reproductive functions. Follicle stimulating hormone and luteinising hormone control the level of hormones produced by the testes and ovaries (such as testosterone, oestradiol and progesterone) and are important in controlling the production of sperm in men and the maturation and release of an egg during each menstrual cycle in women.

During childhood, the levels of gonadotrophin-releasing hormone are extremely low, but as puberty approaches there is an increase in gonadotrophin-releasing hormone which triggers the onset of sexual maturation. No one really knows why this occurs, but it probably involves many different factors.

When the ovaries and testes are fully functional, the production of gonadotrophin-releasing hormone, luteinising hormone and follicle stimulating hormone are controlled by the levels of testosterone (in men) and oestrogens (eg, oestradiol) and progesterone (in women). If the levels of these hormones rise, the production of gonadotrophin-releasing hormone decreases and vice versa.

There is one exception to this rule; in women, at the midpoint of their menstrual cycle, oestradiol (produced by the follicle in the ovary that contains the dominant egg) reaches a critical high point. This stimulates a large increase in gonadotrophin-releasing hormone secretion and, consequently, a surge of luteinising hormone which stimulates the release of a mature egg. This process is called ovulation.

gonadotrophin-releasing hormone

A deficiency of gonadotrophin-releasing hormone in childhood means that the individual does not go through puberty. An example is a rare genetic syndrome known as Kallmann’s syndrome which causes loss of the development of gonadotrophin-releasing hormone-producing nerve cells with a consequent loss of pubertal development and sexual maturation. It is more common in men than women and leads to loss of development of the testes or ovaries and infertility.

Any trauma or damage to the hypothalamus can also cause a loss of gonadotrophin-releasing hormone secretion which will stop the normal production of follicle stimulating hormone and luteinising hormone causing loss of menstrual cycles (amenorrhoea) in women, loss of sperm production in men and loss of production of hormones from the testes and ovaries.

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