If you're driving, a yield sign means that you should slow down, proceed carefully, and be ready to yield the right of way to other vehicles. What could happen if you don't do those things? You could be hit by oncoming traffic.

Yield in investing means something totally different, but the rules for traffic still apply to some extent. If you don't proceed carefully, your investment portfolio could take a hit.

The problem is that sometimes high-yield stocks are very risky bets. However, there are three healthcare stocks with high yields that I think are definitely still worth buying. Here's why AbbVie (NYSE:ABBV), Pfizer (NYSE:PFE), and Welltower (NYSE:WELL) should help your investment returns cruise along in relative safety.

Five increasingly higher stacks of coins with blocks spelling "yield" on top of the stacks.

Image source: Getty Images.

1. AbbVie

AbbVie's dividend currently yields 3.94%, ranking its dividend as one of the very best among big pharma companies. The company places a high priority on its dividend program, increasing the dividend payout by 140% since 2013.

As attractive as its dividend is, though, there are other reasons for investors to really like AbbVie. Probably the most important is the company's growth prospects. AbbVie should be in good shape to increase its earnings by more than 16% annually over the next five years. What makes this growth especially impressive is that AbbVie's top-selling drug, Humira, will begin to face competition from biosimilars in Europe during this period.

But AbbVie isn't too concerned about the threat to Humira. The company has several other rising stars in its portfolio, including cancer drug Imbruvica, hepatitis C drug Mavyret, and endometriosis drug Orilissa. Even better, AbbVie claims the No. 2 pipeline in the industry, according to market research firm EvaluatePharma. The drugmaker's pipeline candidates notably include immunology therapies risankizumab and upadacitinib and cancer drug veliparib.

In addition to its great dividend and strong growth prospects, AbbVie also looks like a bargain right now. The stock trades at less than 11 times expected earnings, in part due to a well-known short-seller stirring up worries about how regulatory changes might impact the company. However, AbbVie CEO Rick Gonzalez recently stated that the Trump administration's changes related to biosimilars and drug rebates shouldn't be significant problems for AbbVie's business.

2. Pfizer

Pfizer's dividend yield stands at 3.21%. While it's still attractive, that's the lowest yield for the big pharma company in a couple of years. It's not because Pfizer has reduced its dividend, though. In fact, the company has boosted its dividend by nearly 42% over the last five years. Pfizer's yield is lower because its stock price has moved higher.

Why is Pfizer stock performing well these days? Beating Wall Street's revenue and earnings estimates in its second-quarter results certainly helped. Pfizer has also enjoyed a streak of good news from its pipeline, with two U.S. and two European regulatory approvals as well as positive results for a key late-stage clinical study. 

The future could look even better for Pfizer. CEO Ian Read told analysts during the company's Q2 conference call that product shortages in its sterile injectables business should begin to improve in the third quarter of 2018. Pfizer also expects a significantly reduced negative impact of declining sales for drugs that have lost exclusivity within a couple of years.

Most important, though, Pfizer has what appears to be its strongest pipeline in decades. The company hopes to win approvals for new indications for existing drugs like Ibrance and Xeljanz. Pfizer's pipeline also includes promising new drugs with blockbuster potential, such as pain drug tanezumab and rare-heart-disease drug tafamidis.

3. Welltower

Welltower boasts the highest dividend yield of these three stocks -- 5.28%. The healthcare real estate investment trust (REIT) has such a great dividend that I have referred to Welltower as "a retiree's dream stock."

I don't view Welltower as only a stock for retirees, though. Every investor should like a stock that pays a high dividend yield and has solid growth prospects. We can sum up Welltower's growth prospects in two words: baby boomers.

Every day, 10,000 Americans on average turn 65. This will increase the population of individuals age 65 and older by 36% through 2025. The number of individuals aged 85 and over in the U.S. is expected to double in the next 20 years. These demographic trends mean that demand should increase significantly for senior housing and post–acute care communities.

Welltower's properties target both of these markets. The company now focuses more heavily, though, on senior housing properties in major high-growth urban markets that are more profitable. As the elderly population grows, so will Welltower's earnings -- and its dividend payouts.

Risks

Investors should be aware of the risks with any stock they buy. And the fact is that every stock comes with some risks.

For AbbVie, the greatest risk is that its pipeline candidates don't achieve the success that is expected of them. The company remains heavily dependent on Humira, so any major pipeline setbacks would hurt a lot. Although Pfizer isn't as reliant on one drug as AbbVie is, the drugmaker also really needs for its pipeline to deliver on its potential. Welltower is exposed to macroeconomic risks. A severe recession, another housing bust, or a major spike in interest rates could damage the company's prospects.

While these risks are real, I don't think that they outweigh the positives for these stocks. In my view, their high dividend yields, established track records, and solid growth prospects make AbbVie, Pfizer, and Welltower good picks for long-term investors.

Keith Speights owns shares of AbbVie and Pfizer. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.