In the U.S., nine out of ten couples with a female partner under the age of 35 who are actively trying to get pregnant succeed within one year. The chance of a pregnancy is about 25% per month. For couples that fail to achieve pregnancy after one year (and for women over the age of 35 after 6 months) fertility testing is recommended to identify any obstacles that could prevent pregnancy.
For the female aspect of infertility, a woman is born with approximately two million non-renewable eggs in her ovaries. Each egg is housed in a sac, and together the egg and sac are referred to as a follicle. Once a month, several of these follicles begin to mature under the influence of follicle stimulating hormone (FSH). FSH is produced by the pituitary gland and travels in the bloodstream. As the follicles grow, they in turn produce two hormones called estradiol and inhibin. These two hormones travel in the blood to the pituitary gland where they turn off the FSH production. Only the most mature egg follicle can continue to grow once FSH production drops. This process prevents too many egg follicles from developing and is important as humans are not litter-bearing and the womb should ideally carry only one baby at a time.Approximately fourteen days after the start of the menstrual period, a second hormone, called luteinizing hormone (LH) is produced by the pituitary gland. This hormone travels in the bloodstream to the mature egg follicle and causes it to rupture in a process called ovulation. Once the follicle sac ruptures, the egg is released from the ovary and swept into the end of the fallopian tube. The remainder of the ruptured follicle remains in the ovary and continues to produce hormones including progesterone, which only appears after ovulation.
In terms of male infertility, or male factor, men produce millions of sperm each day. Following sexual intercourse, sperm swim rapidly through the cervical mucus up into the fallopian tube where they attempt to fertilize the egg. Although sperm can survive for 2-3 days in the cervical mucus, the egg only lives for twenty-four hours. For this reason, the timing of intercourse is very important.
There are a number of variables in the ever-mysterious reproductive system and path to pregnancy. If you have any questions about trying to get pregnant, or need help, feel free to call us at Santa Monica Fertility. We are always happy to help!