You chances getting pregnant based on the menstrual cycle
Your chances and odds getting pregnant depend on several factors such as when and if you ovulate, the amount of sperm in the ejaculate and when during the menstrual cycle, especially in relation to the day of ovulation you have sex.
Day 1-5: Your menstrual period or bleeding
In essence, menstruation is the monthly shedding of the endometrium, the inner membrane of the uterus. For most women, this lasts between three and seven days. By the third day, levels of progesterone and estrogen are on the rise and working on rebuilding your endometrium.
Around day four, follicle ripening begins to go on the uptick. That means the ovaries are starting to prepare eggs for release. Unless you're a very early ovulator (the average timing for ovulation is 14 days before the start of your period -- track yours by using a basal body temperature chart or an ovulation predictor kit), there's little chance your man's sperm will actually have any eggs to work with during this phase of your cycle.
Your odds of conceiving: Almost nil. It's not detrimental to have intercourse, and some women see it as a good time to take a breather from the rigors of frequent baby-making sex.
Pre-ovulation: Ovulation day minus 1-5
"I recommend having sex frequently -- two to three times a week, but every other day if you can -- shortly after you stop menstruating to cover your window of pre-ovulation," says Kelly Pagidas, M.D., a fertility specialist with Women & Infants Center for Reproduction and Infertility in Providence. Here's why: Around day seven of your cycle, you'll notice vaginal discharge that seems a little springy to the touch. Within a few days, it will turn white and creamy, a cue that your fertility is returning once again. It doesn't mean the egg is released yet, but it's a good indicator that ovulation is on the way and that your cervical mucus is a friendly environment for sperm.
Remember, sperm can live up to five days if it's trapped in fertile cervical mucus, so it behooves you to get a few of his swimmers in place. "One study showed that people who had sex only one time during this phase, even four to five days before ovulation, still got pregnant," says Steven R. Bayer, M.D., reproductive endocrinologist at Boston IVF fertility clinic in Boston.
Your odds of conceiving: Good. An egg isn't technically released during this phase but you'll want to step up your sexual routine in the event that you ovulate earlier than planned.
The day of ovulation
Welcome to prime time for conception! No matter how long your periods are, ovulation generally starts about 14 days before your next scheduled period. When it happens, your body temperature rises about a half a degree. But bear in mind that this takes place after you're already ovulating, which could be too late. "That's where ovulation kits becomes so helpful," Dr. Bayer explains. "Once it turns positive, have sex in the next 24 to 36 hours."
Another good indication of fertility is a change in the consistency your cervical mucus. "You'll see vaginal discharge that increases in amount and has the consistency of egg whites, signaling it's the perfect time to have intercourse," Dr. Bayer says. Test yours by sticking your index finger and thumb in your vagina to get a sample, then tapping your finger and thumb together. If the consistency is thin and spreads easily between two fingers, you're good to go.
Your odds of conceiving: High, if you have sex within 36 hours. Any eggs that are released live no longer than 12 hours. In fact, it's best if his swimmers meet your egg within four to six hours of its release. Data show that having every-other-day sex is just as effective as doing it every day, so no need to go crazy getting busy every hour (unless you really want to!).
Ovulation days 1-13: Post-ovulation
Also known as the luteal phase, this final portion of your cycle lasts a minimum of 12 days and as many as 16. Progesterone starts to rise, signaling that the ovaries don't need to release any more eggs this month. Your cervical mucus will dry up and create a plug to prevent any additional sperm from entering the uterus.
It takes about six days for any fertilized eggs to travel to your uterus. If one implants in your endometrium, you'll start to see the rise in human chorionic gonadotropin (hCG), the hormone measured by home pregnancy tests, within a week.
Your odds of conceiving: Low. Once the egg has been released, there's not much that can be done until next month. But there's certainly no harm in having sex if you're in the mood!