Kate took a long time to wake up from the anesthesia, but the egg-retrieval procedure was successful. Whew!

If you've been reaching for the Kleenex as you follow Kate Pearson's struggle with obesity and infertility on This Is Us, brace yourself.

This is not a spoiler alert, but consider some possibilities. Even if she gets and stays pregnant — an eventuality that Tuesday night's episode set up — her weight, compounded by polycystic ovary syndrome (PCOS), could make the nine months a nail-biter. Kate would be at elevated risk of gestational diabetes, preeclampsia, and even a rare but heartbreaking occurrence — stillbirth.

Emmy-nominated actress Chrissy Metz has hinted that happier plot lines are in store. "You're going to be pleasantly surprised," she was quoted by the Hollywood Reporter. "There's some good stuff going on."

For women dealing with PCOS — at least one out of every 10 females — it's all good. No matter what happens, NBC's hit show is bringing attention to a common, complex, life-altering disorder that most people (including too many doctors) know nothing about.

"It's one of my favorite shows. When they said, 'polycystic ovary syndrome,' I jumped off the couch and said, 'Oh, my God!' " said Latasha Shepherd-Brown, 33, of Philadelphia. Diagnosed with PCOS in her teens, she recently underwent bariatric surgery to help with weight loss and perhaps boost her chances of a baby when she and her husband are ready.

So what is PCOS, and do Kate's travails ring true? Here's a brief overview from research and specialists:​

PCOS is the leading cause of female infertility. For reasons that remain unclear, the ovaries produce too many male hormones, particularly testosterone, which disrupts the menstrual cycle and derails ovulation. (Acne and male-pattern hair growth or hair loss are also common with PCOS, although Kate shows no signs.) Experts used to believe the lack of ovulation inevitably made eggs get trapped in their follicles, studding the ovaries with cysts — "polycystic." But it has become clear that some women with PCOS don't have ovarian cysts, and some women with cysts don't have PCOS. As fans know, Kate's fertility may also be hurt by her age (38) and her husband's use of antidepressants.

PCOS turns weight management into a catch-22. Excess testosterone leads to insulin resistance, which can promote diabetes, heart disease, and high blood pressure. It can also lead to obesity by promoting weight gain and thwarting weight loss. Katherine Sherif, a PCOS specialist at Thomas Jefferson University, explained it this way: "Women with PCOS have high levels of insulin, which is a growth hormone. These women will eat the same as other women, but they will put on weight and the other women won't. Their bodies save every calorie." Even so, diet and exercise are cornerstones of PCOS management, along with oral contraceptives, which normalize the menstrual cycle, and metformin, a drug that reduces insulin resistance.

Miscarriage is more common with PCOS. Last season, fans rejoiced when Kate found out she was pregnant — and grieved with her when she miscarried. Early pregnancy loss occurs in a third to half of women with PCOS. Why? Again, insulin resistance and obesity are believed to play significant roles, as well as high levels of an amino acid called homocysteine, which is produced when proteins are broken down.

The role of bariatric surgery in PCOS treatment is unsettled. In the first season, Kate's weight led her to consider bariatric surgery, a procedure to make the stomach smaller. Though bariatric surgery has become a mainstay of treatment for extreme obesity, not many rigorous studies have been done in women with PCOS. A recent review of those studies found surgery improved PCOS symptoms, including male-pattern hair growth, menstrual irregularities, and insulin resistance, but the effects on infertility were inconclusive. International guidelines on PCOS diagnosis and treatment say the "risk-to-benefit ratios currently are too uncertain to advocate [bariatric surgery] as fertility therapy."

Fertility treatments work, but may carry extra risks. When the only fertility problem is lack of ovulation, women with PCOS are usually treated with a drug that induces ovulation. The most invasive, most high-tech resort is in vitro fertilization. An IVF specialist initially refused to take Kate and Toby on as patients, giving her a 90 percent chance of failure. That estimate may be a bit harsh, but as the show accurately portrayed on Tuesday, obesity can add to the risks of going under anesthesia for the egg retrieval. What's more, research suggests PCOS makes the uterine lining less receptive to a fertilized egg, reducing implantation rates.