By: Rachael Rettner, Senior Writer
Published: 05/13/2014 12:02 PM EDT on LiveScience
There are many things couples trying to have a baby can do to boost their chances of pregnancy. But there is also a lot of misinformation out there about fertility, so experts say people should be careful about which advice they heed.
Here are seven common misconceptions about getting pregnant:
It takes a long time to get pregnant after stopping birth control pills.
Many women think that, after they stop taking birth control pills, it will take them six to 12 months to get back to regular menstrual cycles, and that during this time, their chances of pregnancy are reduced.
But studies show this is not the case, said Dr. Jani Jensen, an obstetrician/gynecologist at the Mayo Clinic in Rochester, Minn.
In a study of 200 women who took birth control pills for at least a year, 40 percent had a period or became pregnant just one month after they stopped taking the pill. And by three months post-pill, nearly 99 percent had a period or became pregnant, Jensen said.
Jensen recommended that women who haven't had a spontaneous period within three months of stopping birth control pills be evaluated to see if there's a problem affecting their ability to produce eggs.
Couples who want to have a baby should always try for a year before seeking fertility help.
Doctors in the United States generally define infertility as not conceiving after one year of unprotected sex, but some couples should not wait an entire year to get evaluated if they don't become pregnant.
Studies show that many couples become pregnant within a few months of trying: Among couples without fertility problems, 60 percent will be pregnant within three months, and 75 percent within six months.
Doctors recommend that women age 35 and older try for no longer than six months before seeking a fertility evaluation, Jensen said. Women younger than 35 should still try for a year, unless they have a condition that could make it difficult to become pregnant, such as a menstrual cycle longer than 35 days, Jensen said. In the latter case, they shouldn't wait a full year to seek an evaluation.
Women who monitor their body temperature to boost their conception chances should wait until their temperature goes up before having intercourse.
Monitoring body temperature is one way women can track their fertility over the course of the month and boost the chances of conception. But women shouldn't wait until after their temperatures rise to have intercourse because this temperature rise (about 0.1 degrees Fahrenheit, or 0.6 degrees Celsius) happens after an egg is released, Jensen said.
"If you wait to have intercourse to that point, your chance of success is now reduced by more than half," Jensen said.
Women have the best chance of becoming pregnant if they have intercourse on the day before ovulation, because sperm can live in the female reproductive track for several days, Jensen said.
"What the data seem to suggest is that if there's sperm really ready and waiting at the time the egg is released that that has the best chance of success," Jensen said.
If a man has had a child in the past, he can't be the reason that a couple is infertile.
Some couples think that if they are having trouble getting pregnant, it can't be a problem with the man if he's fathered a child before. But there are many reasons why this is not necessarily true, Jensen said.
"The fact that you had fathered a pregnancy in the past doesn't mean that you have a guarantee for the future," Jensen said.
Many things could have changed in the years since the man first fathered a child. For example, the man could have gained weight or developed thyroid disease, both of which can affect fertility, Jensen said.
There's also a remote possibility that the man wasn't really the father of the child, Jensen said.
Couples should have intercourse every day to increase the chances of pregnancy.
In the days leading up to ovulation, women have a window of time when they can become pregnant. But couples don't need to have intercourse every day during this period — every other day is just as good, Jensen said.
For most women, the "fertility window" is days 10 to 20 of their cycle (counting day one as the first day of menstrual bleeding), Jensen said. So having intercourse every other day in this window is a general recommendation to increase pregnancy chances, Jensen said.
Certain coital positions can increase the chance of pregnancy.
The idea that coital position affects pregnancy chances, or the gender of a baby, is a myth, Jensen said.
"Doing things like lying down with your feet in the air doesn't increase the chance of pregnancy at all," Jensen said.
Expensive vitamins help with fertility.
Some expensive vitamin products are marketed as a way to improve fertility, but the evidence to support this claim is weak, Jensen said. "I strongly urge patients not to take expensive vitamins," Jensen said.