"Oh, just put a pillow underneath your hips during sex, then you'll definitely get pregnant," a good friend told me. "That did the trick for us twice."
Now, the friend is a smart woman. She has a Ph.D. in biology, for Pete's sake. So she must know what she's talking about when it comes to conception, right?
"No, not at all! There's no evidence to support that," says Dr. Jessica Illuzzi, an obstetrician and gynecologist at the Yale University School of Medicine. "Maybe the idea seems logical and some older clinicians still tell patients that, but studies have found no difference."
Turns out my friend and I are not alone.
A surprisingly high number of women ages 18 to 40 are a bit clueless about the ins-and-outs of baby-making, Illuzzi and her colleagues report Monday in the journal Fertility & Sterility.
More than a third of women surveyed think that elevating the pelvis during sex or using specific positions boost the chances of conception. And just 10 percent of women know the optimal time to try each month to get pregnant.
"A remarkably low number of women are aware that you have to have intercourse before ovulation to get pregnant," Illuzzi tells Shots. About 60 percent (including myself) thought the best time was after ovulation.
"The peak window of fertility is the two days before you ovulate," Illuzzi says. "It's probably good to have sex on both days. Some doctors tell couples to have sex every other day, but then they might miss their fertile window."
And sorry, guys: Having sex more than once a day won't boost your chances of putting a bun in the oven. In fact, that frequency may hurt you in the long run, Illuzzi says. "If he ejaculates too often, his sperm count goes down."
After talking with patients for years at the Yale clinic, Illuzzi started worrying that women around the U.S. were less informed about conception and pregnancy than she and her fellow doctors thought.
So last March her team gave 1,000 women an online survey to assess their knowledge about reproductive health. The survey included women across various races, ethnic groups and socioeconomic levels around the country.
"We didn't find very big differences in knowledge across socioeconomic groups," Illuzzi says. More educated women were only slightly more informed, the survey found.
In general, all women had big gaps in knowledge, Illuzzi says, especially in terms of risk factors for infertility and birth defects.
More than half the women surveyed didn't know that folic acid supplements need to be taken at least a month before conception to prevent neural tube defects. And although most women realize that getting pregnant becomes harder and harder as you get older, many didn't realize that aging raises the risk of miscarriages and chromosomal abnormalities, such as Down syndrome.
About a quarter of women didn't know that obesity, smoking and irregular periods can all decrease fertility and that the same goes for a sexually transmitted disease.
"The No. 1 thing women identify as their risk factor for infertility is stress," she says. "But the literature doesn't really support that as a risk factor.
"It's good to destress your life," she adds. "But in the end, stress probably isn't what's keeping you from getting pregnant."
So where can women go to figure out what the problem is when infertility strikes? Talk to your doctor, Illuzzi says. And for more information, check out medical websites run by universities and physicians organizations, such as the American Congress of Obstetricians and Gynecologists.