Infertility and Ovulation
Ovulation problems are among the most common causes of infertility in women. If you are not having regular periods each month — or if your cycle is very long or very short — you may be having problems with ovulation.
The Monthly Ovulation Cycle at a Glance
- Day 1 — An ovulation cycle is counted on the first day of menstrual bleeding. At this time, the lining of the uterus is shed for approximately five days. At the same time, several follicles (the fluid-filled sacs inside the ovaries that contain eggs) begin to mature and develop.
Hormones at work: Follicle Stimulating Hormone (FSH) develops the eggs while estrogen levels rise and cause the lining of the uterus to start building up again.
- Day 14 — About two weeks into the monthly cycle, Luteinizing Hormone (LH) levels rise sharply and within 24 to 48 hours the most mature follicle in the ovaries bursts and an egg is released from the ovary. Some women experience a little twinge of pain in one of the ovaries around this time.
Hormones at work: Following the LH surge and ovulation, the progesterone level rises to prepare the lining of the uterus for the embryo.
- Day 15 — The egg travels from the ovary into the fallopian tube. As the egg nestles in the end of the tube, it may come in contact with sperm. If the sperm penetrates the egg, fertilization occurs.
- Day 20 — The fertilized egg continues its journey to the uterus, where it may or may not successfully implant in the lining of the uterine wall. If the egg was not fertilized, it is simply absorbed.
Hormones at work: As the embryo implants it begins to produce Human Chorionic Gonadotropin (hCG), which maintains the lining of the uterus during the implantation process. By day 28, the hCG levels are high enough that a urine pregnancy test will be positive.
Hormones and the Ovulation Cycle
Over the course of the monthly ovulation cycle, several hormones must interact with each other seamlessly in order for ovulation to occur. For example, as estrogen rises it causes the FSH level to drop (preventing more than one egg to mature). Together with a small rise of progesterone, the LH surge is stimulated, which then causes release of the egg. In effect, each hormone fluctuation dovetails into the next. With this in mind, it’s easy to see how critical it is for each one to perform its role. If even one goes wrong, all the others get thrown off. Fortunately, once any ovulation problems are identified, your fertility doctor can take steps to correct them.