A wave of state abortion bans has set off speculation: What would happen if Roe v. Wade, the ruling establishing abortion rights nationwide, were overturned?

Although far from a certainty, even with increased conservative clout on the Supreme Court, a reversal of Roe would mean abortion policy would revert to the states, and many would be eager to impose bans.

What would not happen is a full-fledged turning back of the clock to 1973.

Women now have far more methods to avoid unwanted pregnancies, as well as safer, easier options for abortion. Many abortions are induced at home with a two-drug combination, and advocacy groups are spreading the word about home abortions using one of the drugs that can be done without a medical professional’s involvement.

“I don’t think you can put all those different genies back in the bottle,” said medical historian Andrea Tone at McGill University in Montreal. “Women are in charge of their procreative destiny. I don’t think women will put up with the absence of privacy and discretion that birth control and abortion provide.”

Here’s a look at some of the abortion-related changes that have unfolded since 1973:

At the time of Roe, abortion was broadly legal in four states, allowed under limited circumstances in 16 others, and outlawed under nearly all circumstances in the rest. A reversal of Roe would produce a patchwork map where perhaps 15 or so states would continue to make abortion easily accessible, a dozen or more would ban virtually all abortions unless the mother’s life is at stake, and the rest would thrash out their response in the public arena and the legislatures.

In 1974, a year after Roe, there were about 899,000 abortions in the U.S., according to the Guttmacher Institute, a research organization that supports abortion rights.

The number of abortions rose steadily, peaking at 1.61 million in 1990, before starting a steady decline — falling to 926,200 in Guttmacher’s latest national survey, covering 2014. Close to 90 percent of the abortions occur in the first 12 weeks of pregnancy.

The decline is attributed to increased availability of effective contraception and a sharp decrease in unintended pregnancies, notably among teens. In 1974, teens accounted for 32.5% of abortions in the U.S.; in 2014 that dropped to 12%.

Technology and science have given women unprecedented options and control over fertility since 1973. Back then, single women had only recently gained nationwide access to birth control, thanks to a 1972 Supreme Court ruling, said Dr. Sarah Prager, who directs the University of Washington School of Medicine’s family planning fellowship.

“This is recent history,” Prager said. “Now we have these incredibly effective contraceptive methods available.”

A woman can get the morning-after pill without a prescription and keep some in her medicine cabinet for emergencies. Her smartphone sends birth control reminders. Or, if she prefers, a matchstick-size implant gives her no-hassle contraception for years at a time.

Surgical abortion has become safer, employing tools that use vacuum pressure rather than scraping. There’s increasing use of the medication alternative: Ending a pregnancy with mifepristone and misoprostol now accounts for about 30% of U.S. abortions.

“It’s safe and comfortable,” said Missouri resident Lexi Moore, 30, who ended a pregnancy in September with a prescription from Planned Parenthood. “You get to sit in the comfort of your home instead of doing it in a clinic or in a back alley. … You will have cramps, like a heavy period. But it’s worth it in the end, and you have control over that.”

Moore had to drive 70 miles to pick up her prescription and, lacking insurance, paid $800 out of pocket. But she welcomed the outcome, and wrote thank-you cards to the clinic.