5 Little-Known Pregnancy Facts That Will Surprise You

By Linda Geddes

If you thought women were the only ones who needed to cut down on stress when trying to conceive, think again. Psychological stress can also affect sperm quality, reducing its concentration, appearance, and ability to fertilize an egg, according to a recent study of 193 men led by Columbia University.

Men who experienced two stressful life events, such as the death of a loved one, in the past year had poorer quality sperm than those who experienced no such events. Unemployed men also had worse quality sperm, on average, than employed men – although general work-related stress didn't seem to have an effect.

Once you actually get pregnant, there are more surprises in store. Here are five other things about pregnancy that your OB-GYN probably hasn't told you:   

Men can get pregnancy symptoms, too.
Up to half of men are thought to experience some symptoms of Couvade Syndrome, or sympathetic pregnancy—although not all physicians agree on that. The most common symptoms are loss of appetite, toothache, nausea, sickness, and anxiety. If this sounds a little too much like male hypochondria to you, there may also be a physical explanation: rising levels of the hormone prolactin, which is more commonly associated with breastfeeding.

What's a breastfeeding hormone doing in expectant fathers? While men don't usually produce enough prolactin to trigger lactation, this can happen — certain medical conditions, including pituitary tumors, occasionally result in the production of "man milk." But prolactin may have other benefits for new dads, including making them more likely to interact with their baby. 

Unborn babies can taste what their mom is eating.
Take a draft of amniotic fluid from a woman after she's eaten a garlicky meal and you can smell the garlic wafting off it. Smelly molecules from a women's diet get into the amniotic fluid by the same mechanism they make their way into breast milk via the blood. And babies, who literally breathe amniotic fluid during their time in utero, can detect them as they already have smell receptors in the back of their noses. This early exposure to tastes and smells in mom's diet may even serve to shape their preferences in later life. Several studies have shown that babies whose moms ate a lot of garlic or aniseed during pregnancy were attracted to these smells after birth.

Pregnancy really does change your brain.
You've probably heard of momnesia, or pregnancy-related forgetfulness, but pregnancy triggers other changes in the brain as well. For one thing, women's brains shrink during late pregnancy, and don't usually return to their normal size again until around six months after birth. The impact of this shrinkage isn't yet fully understood, but it may be a physical manifestation of the structural reorganization that's taking place. Animal studies have suggested that pregnancy triggers the growth of new brain cells in the brain's memory center, the hippocampus. It also seems to trigger improvements in their navigational skills and memory for places.

Human studies also hint at some behavioral changes brought about by pregnancy. Women may become more sensitive to facial expressions including fear, disgust, and anger. They also appear to be less fazed by stressful situations during late pregnancy.

Unborn babies can detect their mother's mood.
If the sight of Julie Andrews prancing around the mountains singing, “The hills are alive...” lifts your spirits, spare a thought for how it might be affecting your baby. One recent study found that fetuses whose moms were shown this movie clip waved their arms around and made more movements overall than when their moms viewed a sad movie. It's difficult to know whether this meant that the babies shared their moms' enthusiasm for the film, but it's a hint that unborn babies are already tuned into their moms' emotional responses.

Cells from your baby live on in your body after birth.
Having a baby changes you in more ways than you might imagine: From early pregnancy onwards, you will forever carry a little piece of your baby around with you in the form of fetal cells circulating in your blood or surviving in your bone marrow. There are even hints that these cells may function as a kind of repair kit for mom: Women with breast and other cancers seem to carry fewer of these cells than healthy women, while studies have also found signs that fetal cells may help patch up some of the physical damage to the liver caused by hepatitis C. And it's a two-way street. In all likelihood, you are still carrying around some of your mom's — maybe even some of your grandmother's cells — in your own blood.

Linda Geddes is a London-based magazine journalist who writes about biology, medicine, and technology. She has worked as both a news editor and reporter for New Scientist magazine. She has received numerous awards for her journalism including the Association of British Science Writers’ award for Best Investigative Journalism and the European School of Oncology’s Best Cancer Reporter. She was also shortlisted for the Paul Foot Award in 2011 and the Press and Periodicals Association’s Writer of the Year award in 2009, 2011, and 2012. Her book, "Bumpology: The Myth-Busting Pregnancy Book for Curious Parents-To-Be," was published in March 2014.