It could be something as dramatic and public as the terrorist attack, or it could be something highly personal, such as the death of a loved one or the loss of a job.
Either way, if you're pregnant and you're under significant stress, studies show there could be some serious consequences if you don't relieve the pressure.
The consequences of stress
"Although research in this area is still new, it has become increasingly clear that, for many women, stress during pregnancy can have some adverse consequences, including an increased risk of premature labour, premature birth and low birth-weight babies," says Dr Michael Paidas, director of maternal-foetal medicine at New York University Medical Centre.
Additionally, studies have also shown experiencing extreme stress during pregnancy can increase the risk of miscarriage, preeclampsia (a dangerous form of high blood pressure in the mother), and even birth defects.
Not all stress has such negative consequences
The important thing to remember is that not all women react to even major stresses in the same way, so not all pregnant women who experience stress will have a negative outcome, Paidas says.
Often, what can make the difference is how early the stress is recognised and steps taken to offset the risks, doctors say.
Among the most important steps a woman can take: Talking to her doctor about even that small stress she may feel about becoming a parent.
"Many women don't realise that all mothers-to-be, particularly first-time mothers, have feelings of apprehension and even fear - about their baby's health, about the delivery, about the pregnancy itself," says Dr Stephen Chasin, director of high risk pregnancy at New York Weill Cornell Medical Centre.
If you keep those feelings bottled up, he says, stress levels rise. Discuss them with your doctor, however, and you may find you have little to fear.
You can also join a support group of your peers - sharing your feelings about being pregnant with other pregnant women.
"For a lot of women, particularly those undergoing severe types of stress, support groups or peer groups can be really helpful. Talking about it, and seeing that other people are having the same fears and same stresses that you are, can help reduce your own stress," Chasin says.
In addition, experts say if you took anti-anxiety medication before getting pregnant, you should talk to your doctor about continuing to do so after becoming pregnant.
"The question isn't whether a medication has the potential to cause harm during pregnancy, but whether the harm of taking the medication is outweighed by the harm of not taking it," Chasin says.
The March of Dimes also suggests that pregnant women can reduce stress by using a number of different relaxation therapies. Among those recommended include biofeedback, meditation and guided imagery.
Keep an eye on your weight
While most pregnant women who are experiencing stress recognise the signs in time to seek treatment, this isn't always the case. Indeed, experts say that because so many of the physiologic symptoms of stress - difficulty sleeping or gastrointestinal upsets - mirror a normal pregnancy, it can be hard to tell just how stressed you really are.
One way to tell, say experts, is to keep your eye on your weight.
"Failure to gain the proper amount of weight during pregnancy is usually a sure sign that you are suffering from stress," Chasin says.
Correcting the problem as early as possible can help you avoid a number of serious complications, Chasin says.
A new French study published in the American Journal of Epidemiology shows that low weight gain, in conjunction with depression and anxiety, during pregnancy can increase the risk of pre-term labour.
If you find you are not eating well during your pregnancy, or if you are eating and still losing weight, Paidas says you should visit your doctor and discuss not only the weight problem, but any stresses you may be experiencing.
Tips to keep on track
If you find you are experiencing stress, the March of Dimes offers these tips to help keep your pregnancy on track:
- Eat regular nutritious meals and take a multivitamin containing folic acid every day.
- Drink at least six glasses of water a day.
- Get adequate rest and try to find a window of opportunity each day to participate in a relaxation activity.
- With your doctor's OK, participate in an exercise program.
- Avoid alcohol, cigarettes or herbal products designed to alleviate stress - particularly since there is little long-term safety data about effects on baby's health.
- Talk about your fearful or stressful feelings - to your partner, family, friends and to your doctor.
- If you find you can't sleep, or have problems eating, or feel overwhelmed by your emotions, talk to your doctor right away.