Amy Lembcke once dreamed of twin babies -- of using aggressive in-vitro fertilization to overcome infertility and conceive her family in one swoop.

But when the time came to pursue IVF, Lembcke backed off. She didn't want to risk the money or toll on her body for a procedure that could produce a baby, or no baby, or more babies than she bargained for.

"I didn't want to take out a loan or a second mortgage on the house just to try to have a baby," said Lembcke, 29, of St. Paul, "because they come with their own expenses."

Lembcke's change of heart helps explain a surprising turnaround in Minnesota -- a decline in multiple births from 2,599 babies in 2009 to as few as 2,297 last year. Multiple births had increased almost every year for the past two decades, mostly because of the popularity of assisted reproduction techniques such as IVF -- by which embryos are fertilized outside the body and then implanted in infertile women.

So while the decline in multiple births is small, it is significant. Public health and fertility experts suspect that the struggling economy discouraged couples such as the Lembckes from pursuing expensive fertility treatments. (IVF can cost around $15,000, and insurance coverage of the procedure is spotty.)

But the decline also marks improvements in infertility procedures; Minnesota's five IVF clinics are all reporting more pregnancies over the past decade but fewer twin and triplet births.

Preliminary figures from the Minnesota Department of Health for 2012 show no quadruplets or higher order births and only 65 babies born as triplets -- a decline from 92 in 2009 and well shy of a high of 167 in 2001. The data also showed fewer twin births, which surprised fertility doctors because many of their patients want twins.

"We've done a very good job at almost eliminating the triplets," said Dr. Jacques Stassart, medical director of Reproductive Medicine and Infertility Associates, which provides IVF in Edina and Woodbury. "The next frontier is to curb the number of twins, though we're meeting a bit of patient resistance to that."

The trouble with twin births is that they double the risk of babies being born prematurely or with birth defects that can result in lifelong disabilities. A sustained decline in multiple births could have significant cost savings for Minnesota's health care system because fewer newborns would need costly neonatal intensive care.

"It's not completely wrong" to want twins, said Dr. Eric Widra, an IVF provider in Washington, D.C., and the chairman of the practice committee for the U.S. Society for Assisted Reproductive Technologies. "If the kids do well, then you have two kids. And if that's how you see your family, then you get a lot of the hard work out of the way early. But from a public health standpoint, you have to look at the differences in risk and the differences in cost."

Reversal of a trend

Last January, a federal study reported record twin births in the United States, but it was based on 2009 data. Now 2010 figures are out for the nation and -- like the Minnesota figures -- they show a decline in twin and triplet births.

"I don't know if it will continue or not, but it's important because the rate had been going up fairly steadily," said Joyce Martin, a birth trends researcher for the National Center for Vital Statistics.

The economy has been linked to a decline in births overall that started with the 2008 recession. Minnesota births declined from 73,664 in 2007 to 66,330 last year. But since 2009, the number of multiple births has declined 12 percent while total births only declined 6 percent.

After trying with her husband for a couple of years to have a baby, Lembcke was diagnosed with a hormone imbalance that made her infertile. She became fixated on ways to get pregnant. The notion of a multiple birth was hardly a concern.

"We did fertility treatments for about six months," she said. "I tend to be overly involved when I'm doing things, and it became too much for me. It took a toll on my marriage. It changes who you are."

Lembcke also worried about the physical toll of taking hormone drugs to produce eggs for the IVF process. So she instead searched for ways through diet and exercise to correct her hormone imbalance and improve her chances of pregnancy.

"It's not about getting pregnant at all costs," she said. "It's about starting a family."

Stassart believes the decline in multiple births is due to improvements in assisted reproduction and fertility specialists recommending more conservative attempts to patients.

Fewer embryos implanted

In 2001, nearly half the women 35 and younger who got pregnant through IVF at Stassart's clinic had multiple births. By 2010, only one-third of those pregnancies resulted in twins or more.

Many of the high-profile stories of multiple births -- such as the Morrison sextuplets born in Minneapolis in 2007 -- were the result of women taking fertility drugs. But IVF certainly contributed to the rise of multiple births over the past two decades. When doctors produced multiple embryos in vitro, they often implanted two, three or more in women to maximize their odds of pregnancies.

That, too, has changed. The average number of embryos transferred in women younger than 35 at Stassart's clinic, for example, dropped from 2.8 in 2001 to 1.8 in 2010.

Stassart was one of the first fertility doctors in the nation to offer single-embryo transfers with a guaranteed second attempt if the first one failed. Few women took up the offer at first, not wanting to reduce their odds after long struggles trying to conceive. But now, a quarter of eligible women at his clinic try it, and 75 percent get pregnant, he said.

The "unsung hero" is improvements in the freezing of embryos that safely preserve them for future attempts, Stassart said. "Fifteen years ago, it was use them or lose them." Now couples are willing to try single-embryo transfers because they know the frozen embryos can be thawed and used in second attempts.

Odds have improved

Widra said the national society representing fertility clinics now recommends single-embryo transfers for younger, healthier women.

"If you have two top-quality embryos, especially at a young age, there is really minimal if any difference in taking home a baby in transferring one versus two embryos," Widra said. "You're just increasing your chances of twins with two."

Lembcke knows that the odds of IVF have improved even since her battle with infertility started four years ago. But she isn't going back, even though her efforts at naturally improving her fertility didn't work. She and her husband are now pursuing adoption.

"It's expensive to adopt, as well," she said, "but we discovered when we made that decision that we felt relief. Because at the end of the journey we knew there was going to be a child there."

Jeremy Olson • 612-673-7744