From Dr. Jennifer Haythe, M.D. Cardiologist for the Center for Advanced Cardiac Care and Co-Director of the Women’s Center for Cardiovascular Health at New York-Presbyterian Columbia University Medical Center.
I was scrolling twitter recently and came across a recent study in the Australian and New Zealand Journal of Obstetrics and Gynecology looking at women and their understanding of fertility. Shockingly, a mere 13% of surveyed women could correctly identify their “fertile window.” I realized we are doing a terrible job of educating young women on their menstrual cycles. When I was trying to conceive, I read a fabulous book called “Taking Charge of Your Fertility” by Toni Weschler, MPH – and I highly recommend picking up a copy for a long and thorough explanation. But for the basics, keep reading.
First of all, every woman is different and menstrual cycles can vary from 20-40 days with most women experiencing cycles about 28 days long. The following explanation will be based on a 28-day cycle. However, if you learn to read your body’s symptoms you will be able to know what phase you are in regardless of the duration of your cycle.
Menstruation Days 1-5 (can be shorter or longer!)
Menstruation or “your period” is the shedding of the lining of the uterus when pregnancy does not occur. Typically, women bleed for 3-7 days. Women can feel crampy or bloated, experience headaches and nausea, and general malaise.
Follicular Phase Days 5-14
During this phase your body prepares a follicle for ovulation. Your pituitary gland secretes FSH stimulating between 10 and 20 follicles to develop. In turn, they secrete estrogen, which causes the lining of the uterus to thicken in preparation for possible pregnancy. Only the best and the brightest egg will be released at the time of ovulation. As estrogen levels rise and ovulation approaches, a woman’s cervical mucus will also change. (It’s NOT gross so just get over it because it’s a great way to predict fertility). Women have mucus throughout their cycle, but “fertile mucus” is different. It has the consistency of egg whites and is clear, stretchy and slippery. Sometimes you may notice it dangle down while sitting on the toilet. Fertile mucus not only lets you know when you are about to ovulate but also helps the sperm swim towards the egg. High levels of testosterone during this period serve to increase your libido and interest in sex.
In addition, your cervical position may change. Practice placing your fingers into your vagina and feeling the position of the cervix. As ovulation approaches the cervix will move up and its opening widens.
There are also changes in your body’s temperature leading up to ovulation and some women track these changes using a thermometer to help understand when ovulation is set to occur.
Ovulation Day 14
When estrogen levels reach a peak, luteinizing hormone (LH) is released by the pituitary causing the follicle to release the egg. Some women can actually feel when they ovulate. Mittelschmerz is German for “middle pain” and is a sharp one-side lower abdominal pain some women feel when the egg is released from their ovary. Ovulation predictor kits work by detecting the surge in LH in your urine.
Here is the key fertility point for those trying to conceive: an egg can live for 24 hours but normally lives for only 6-12 hours, while sperm can live for up to 3 days. Ideally, sperm are waiting patiently in the Fallopian tube at the time of ovulation. This means that intercourse should ideally take place in the 5 days before ovulation. You need the sperm to be ready and prepared so they don’t miss the window of opportunity. Intercourse after ovulation is less likely to result in a pregnancy, and certainly more than 24 hours after ovulation intercourse will not result in pregnancy.
Luteal Phase Days 15-28
Remember your follicle that released the egg? Well that changes into the corpus luteum once the egg has left. The corpus luteum secretes large levels of progesterone and some estrogen, which help maintain and even further thicken the lining of the uterus for possible conception/implantation. If pregnancy does not occur, and implantation does not result, the corpus luteum breaks down and progesterone levels plummet. It is actually the drop in progesterone (and estrogen predominance) that causes typical PMS symptoms of breast tenderness, headaches, mood swings, poor sleep, and fluid retention. Cervical mucus during the non-fertile phases of your cycle can be sticky, crumbly, gummy or creamy. When progesterone levels drop low enough, the uterine lining disintegrates and menstruation starts.
By understanding this simple cycle that happens to your body every month you will be better prepared for your period and better prepared for trying to conceive.