A renewed push by several states to restrict access to abortions could have negative consequences for the health and well-being of women, as well as their children, research has shown.

Since January, eight states have passed laws that ban abortions well before 24 to 28 weeks of pregnancy – the fetal viability standard most states follow that stemmed from the 1973 Roe v. Wade U.S. Supreme Court ruling. The recent abortion bills passed by Georgia, Kentucky, Mississippi, Missouri and Ohio set restrictions as early on as six weeks, with Alabama legislators voting to ban nearly all abortions. None of these laws has taken effect and all are expected to face legal challenges.

Research at UC San Francisco and elsewhere has shown that without access to abortion services, more women carry unwanted pregnancies to term and that this can have negative health consequences for these women and their families.

Diana Greene Foster, PhD, a professor in the Department of Obstretrics, Gynecology & Reproductive Sciences and director of research at Advancing New Standards in Reproductive Health (ANSIRH), has done groundbreaking work on the effect of unintended pregnancy on women’s lives. She leads the nationwide Turnaway Study, the first major longitudinal study examining the physical and social consequences for women who have been denied wanted abortions. She answered some questions about the new wave of abortion restrictions nationwide.

So what is the significance of the new restrictions in many states that limit abortion to six or eight weeks of pregnancy?

Pregnancy is, first of all, measured by most physicians from the beginning of the woman’s last period – which is earlier than conception.

If the restriction is for the first six weeks, then under the best possible circumstances, where you have regular periods and you notice the minute it doesn't show on time, you would only have two weeks to find an abortion. But that best-case scenario does not describe many, many women who don't have regular periods and therefore wouldn't miss it in time.

It means lots of women won't know that they're pregnant in time to get an abortion. As a result, women with enough money will travel out of state. Young women and women who are poor will probably end up carrying pregnancies to term that they preferred to terminate.

Some women may turn to non-clinical methods. For example, ordering pills online, trying to circumvent the medical care system. More women will do things on their own without the help of a clinician.

Based on the research, what is known about what happens when women do not have access to legal abortions?

In the Turnaway Study, we compared women who were able to get an abortion to women who were denied one and followed them for five years. Most of the women who were denied were already in the second trimester, beyond the point where they could order pills online. So nearly all the women carried the unwanted pregnancy to term.

When you ask women, “Why do you want to have an abortion?” their reasons for wanting to have an abortion are a good predictor of what the consequences are when they're denied. For example, the most common reason is that women say they can't afford to have a child right now, or have another child right now. We find large economic differences: the women who are denied are more likely to live in poverty, less likely to be fully employed, more likely to report that they don't have enough money basic living expenses, compared to women who have received an abortion.

Women who received an abortion were 50 percent more likely to set an aspirational plan and achieve it – such as finishing their education, getting a better job, giving a good life to their children, being more financially stable – compared to women who were denied an abortion.

What has been shown to be the health consequences for the woman?

There are much greater physical health risks of carrying a pregnancy to term and giving birth than there are of having an abortion, even a later abortion.

Women report more serious complications from birth than they do from abortions. Six percent of women who gave birth compared to 1 percent of women who received an abortion reported a potentially life-threatening condition, things like preeclampsia and postpartum hemorrhage. And there are physical health consequences of being denied an abortion that last for up to five years.

What are the consequences for the woman’s existing children and the children born from unwanted pregnancies?

We find that when women are denied an abortion, their existing children do worse in two areas in particular. One is in achieving developmental milestones having to do with language and motor skills, and social and emotional skills. The other is in the economic health of the household – they are more likely to be living in homes where there's not enough money to pay for food and housing and transportation.

We also looked at the next child born after a woman was able to receive an abortion compared to the child born because the woman was denied an abortion. The kids born after an abortion were themselves more likely to come from a planned pregnancy, they are more likely to have positive maternal bonding with their mother. They're less likely to live in poverty than children who are born because the woman was denied an abortion.

What do we know about women who seek later abortions?

Lots of people, when they think about women having later abortions, kind of blame the woman, asking things like, “Why didn't she come in earlier? What was she doing? Was she just struggling with the decision?” That's not what we find at all.

One of the major things that slow women down is not realizing they were pregnant in the first place. In our study, two-thirds of women who sought abortions after 20 weeks did not know they were pregnant until after eight weeks. Nearly all women reported logistical delays: 38 percent said they did not know where to go for an abortion, 27 percent said they had difficulty getting to an abortion facility, and 65 percent said they could not afford the cost.

Young women, teenagers, and women who have never been pregnant before are more likely to not realize that they're pregnant. There are other reasons people can be late in recognizing a pregnancy: having just had a baby or having irregular periods for a whole bunch of reasons, including contraceptive use and various health conditions.

Once a woman is late in realizing she’s pregnant, everything becomes much harder about getting an abortion. It becomes more expensive. You have to travel farther to find a provider who's willing to do it. If you start being a little late, all the delays snowball sometimes to the point where women are too late to get an abortion at all.

Why is it important to study the health consequences of women’s access to legal abortions?

Abortion is often seen as just a political issue, but one-quarter of American women will have an abortion over their life, so it is extremely common. And the risks around pregnancy are some of the greatest risks that women of reproductive age face. These are major public health and medical care questions – the safety of providing abortion, the safety of pregnancy and delivery, and making sure that women face those risks voluntarily.

The Roe v. Wade decision says women should have access to abortion in the first trimester and prior to the viability of the fetus. I hope that if the new bans go to the Supreme Court, that the Supreme Court takes into consideration the real harms of restricting access to abortion for women and children.