Dear Doctor: I normally get a flu shot every year, but now I'm pregnant and have read that the vaccine might cause miscarriages. Is this true?

Dear Reader: First, let's explain why this is an issue: Pregnant women who contract influenza are more likely to develop complications from the influenza virus. The most striking example of this occurred during the H1N1 pandemic in 2009, when pregnant women accounted for 5 percent of virus-related deaths, but comprised only 1 percent of the population.

In general, pregnant women with influenza are more likely to require hospitalization and more likely to end up in the intensive care unit. They also have a greater likelihood of giving birth to children with cleft lip, neural tube defects (spina bifida), hydrocephalus (increased fluid within the brain) and heart defects. These complications of influenza led the Centers for Disease Control and Prevention in 2004 to recommend that all pregnant women get the influenza vaccine, regardless of trimester.

Now let's look at the safety of the vaccine itself.

A recent study in the journal Vaccine obtained data from health care organizations in five states about women who were pregnant during the 2010-2011 and 2011-2012 flu seasons. The authors determined which ones had been vaccinated with the standard influenza vaccine and which ones suffered a spontaneous abortion, or miscarriage. They found that 485 women had a miscarriage; they then compared these women to 485 pregnant women who didn't have a miscarriage.

The major difference was seen among women who were vaccinated the year before they were pregnant and then repeated the vaccination when they were pregnant. Of those, 17 women in the miscarriage group had the vaccine within 28 days prior to the miscarriage. Women in the group who didn't have miscarriages were five times less likely to have had the flu vaccine in that preceding 28 days.

It's possible that an inflammatory response could be to blame for the miscarriages. Because the first shot primes the immune system, the second shot gives a greater immune response, leading to inflammation. Excessive inflammation can then lead to a spontaneous abortion.

However, the authors stressed that their study found a correlation, not a causation. Here are some other factors that emphasize the far-from-conclusive nature of the study:

First, the number of women in this part of the study was small: 17 in the miscarriage group and four in a group who didn't have a miscarriage at the same time. Second, women at increased risk of miscarriage may be more likely to seek medical help and thus be more likely to get a flu shot.

Obviously, a larger study is needed to verify -- or repudiate -- the possible connection. But, ethically, this may be difficult. A researcher would have to compare pregnant women who had the flu vaccine the year before, and give one group the flu shot in the first weeks of pregnancy and not the other. Yet the risks of going unvaccinated are simply too great.

Until we have further data, I would recommend flu shots in pregnancy to prevent the risk of maternal death and birth defects.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Now that I've turned 50, I need to get a colonoscopy, but I just can't drink that disgusting prep solution. I've tried three different times, but I wind up so nauseated that I can't finish. Is there any other way to prepare?

Dear Reader: Let us reassure you that you're not alone in your struggles with preparing for a colonoscopy. Many of our patients say that the procedure itself is a breeze compared to drinking the solution. However, the preparation phase, which thoroughly empties the intestines, is vital to a successful procedure. Alternatives do exist, but they don't have the same effect, and therefore the results of the colonoscopy may not be as accurate or useful.

A colonoscopy is a procedure in which a gastroenterologist examines the inside of your colon and rectum using a long, flexible tube. Known as a colonoscope, it's equipped with a lighted tip and a camera. A colonoscopy can reveal whether colon tissues are irritated or swollen, if polyps have formed, and whether cancer is present. When polyps are found, a small wire loop on the colonoscope can be used to remove them.

For the best view, the colon must be clean. In fact, the state of your colon is the most important variable in the exam. Unless every last vestige of fecal matter has been eliminated, it's possible that polyps, which are small growths with the potential to become cancerous, or other abnormalities may be missed.

And here's where the dreaded prep solution comes into play. Available under brand names like Golytely, Colyte, Nulytely and Trilyte, these are powders that consist of a laxative, along with essential electrolytes like potassium and sodium. You mix the prep powder with 4 liters of water and drink it according to your doctor's orders.

The laxative, along with the volume of water, empties and cleanses the bowel. The added electrolytes compensate for those you are losing. Because electrolytes are basically salts, the prep solution tries to compensate for the taste with the addition of super-sweet flavorings. The mix of the two, as you have found, is challenging.

An alternative is a low-volume prep solution that you mix with significantly less water. You still have to drink a full 4 liters of fluid prior to the exam, but other than the 2 cups or so of the low-volume prep solution, the rest of that 4 liters can be water or any other clear liquid.

But -- and this is important -- low-volume prep solutions won't get the colon as clean. Also, there is the risk that your electrolytes can be sent out of balance. If there's really no other way, then discuss the low-volume prep with your doctor. And if you're willing to give traditional prep just one more go, try these tips:

-- Chill the solution well before drinking.

-- Sip it through a wide straw (it'll go faster) placed far back on your tongue.

-- Alternate gulps of solution with sips of something that tastes good.

It's not fun and it's not easy, but it's worth the investment because you'll get the best results from your colonoscopy. And, remember: When it's caught early, colon cancer can be successfully treated.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: I am a 72-year-old male with no health problems other than GERD, which is well-controlled, and neurological problems associated with a back injury and surgeries. But in the past eight months, I've gone from 189 pounds to 142 pounds. Initially, I attributed this to stress over my wife's death six months ago, but now I don't know. A general physical, along with blood tests, CT scans of the chest and head, and X-rays of the chest have found nothing unusual. What should I do?

Dear Reader: I can understand why you're worried. Although unexplained weight loss is relatively common -- an estimated 15 to 20 percent of adults over 65 will have unintentional weight loss if followed over 10 years -- your degree of weight loss needs to be investigated further. After all, you've lost 25 percent of your initial weight.

In 15 to 37 percent of cases, cancer is the underlying cause of unintentional weight loss. The tests you list show that your doctor has searched for a possible malignancy and ruled out many cancers already. He or she should also rule out gastrointestinal malignancies. Together, a colonoscopy and upper endoscopy can detect cancers of the colon, stomach and esophagus.

Other potential causes of weight loss, seen 10 to 20 percent of the time, are stomach ulcers, inflammatory bowel disease or another gastrointestinal disease. I would expect some symptoms with this, such as poor appetite, stomach pain or diarrhea. Again, an endoscopy and colonoscopy can help rule out these causes.

As for infection, that too can be a cause of weight loss, but it's often associated with sweats and fevers, and the imaging studies or blood work likely would have found the cause. Similarly, blood tests would have identified high thyroid levels, uncontrolled diabetes and adrenal insufficiency, all of which can lead to weight loss.

Potential illness aside, studies have shown a consistent small degree of weight loss among people who lose a spouse, especially among older couples. For some, the weight loss is largely a side effect of difficulties in food preparation, especially if the person who passed had been the one preparing the meals. In those scenarios, taking a more active role in food shopping and preparation, or having a service deliver meals, are both good options.

But for many people, the cause is not focused on the practical, but is rather much deeper and more complex. The loss of a partner -- especially if it was unexpected -- is clearly traumatic. For that reason, I want to gently suggest that you not discount psychiatric causes as a reason for your weight loss.

Anxiety and depression can cause a decrease in appetite, which in turn leads to weight loss. Depression can also lead to isolation and dampen the desire for certain activities, such as exercise, which then leads to decreased muscle mass and weight loss. Bereavement groups, other family members or religious organizations can help manage these feelings, as can psychological therapy. For extreme cases, anti-depressants such as mirtazapine might be needed to help boost both mood and appetite.

Because many of the physical causes appear to have been ruled out, and the weight loss coincides with the passing of your wife, I would encourage you to get help adjusting to the changes you've experienced. Difficult though it may be, now is the time to focus on the life ahead.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)