In 2007, for the first time since 1973, five Supreme Court justices expressed grave concern with late-term abortions, in a case called Gonzales v. Carhart, and upheld the federal Partial-Birth Abortion Ban Act.

Numerous lawyers and elected officials read the Supreme Court’s decision and thought the Justices were serious. So, since then, 21 states have enacted a prohibition on abortion after five months (20 weeks) (Nebraska (2010), Alabama (2011), Idaho (2011), Kansas (2011), Oklahoma (2011), Arizona (2012), Georgia (2012), Louisiana (2012), Arkansas (2013), Indiana (2013), North Carolina (2013), North Dakota (2013), Texas (2013), Mississippi (2014), West Virginia (2015), Wisconsin (2015), Ohio (2016), South Carolina (2016), South Dakota (2016), Kentucky (2017), Iowa (2017)).

Federal law can reach some areas where state law cannot, so it’s long overdue for Congress to enact a five-month limit too. There are many reasons to do so, but two stand out.

First, since the Supreme Court legalized abortion in 1973 in all 50 states, for any reason, at any time of pregnancy, there have been repeated incidents of late-term abortions and live-birth abortions. The 2013 murder conviction of Philadelphia abortionist Kermit Gosnell—who opened his shop right after Roe v. Wade—was only the latest and most widely-publicized of a string of late-term abortionists prosecuted for killing, or attempting to kill, babies born alive after abortion.

Back in 1973, the justices thrust the nation into this terrible situation by arbitrarily legalizing abortion up to fetal viability (and beyond). The Court’s “viability rule” has isolated the U.S. as one of only four nations (including China, North Korea, and Canada) that allows abortion for any reason after fetal viability. A terrible legacy, which the justices have repeatedly ignored, as they did last year when they struck down Texas health and safety regulations on abortion clinics (the Hellerstedt case), dismissing Kermit Gosnell as just a bad guy who wouldn’t be stopped by any law, a very strange prejudice to be imposed on the states by federal judges.

But there is a second compelling reason why a five-month (20-week) limit is common sense: late-term abortions are considerably more threatening to women’s health. The increased mortality from late-term abortions is as clear as any medical fact can be in America’s 45-year-old dysfunctional system of voluntary data-reporting by abortionists. A 2004 medical study published by Dr. Linda Bartlett in Obstetrics & Gynecology found that the relative risk of abortion-related mortality jumped from 14.7/100,000 at 13-15 weeks gestation. It doubled by 16-20 weeks and doubled again at or after 21 weeks. Add to that the risk of inaccuracy of gestational dating by doctors and a clear legal limit at 20 weeks is necessary to protect women.

Why 20 weeks? Because current Supreme Court case law, and the best available medical evidence, provide the strongest support for a limit at that time, but unfortunately no earlier. The medical evidence of fetal pain is strongest at 20 weeks. And the best medical data (the Bartlett study) shows the greatly increased rate of maternal mortality after 20 weeks. And the Court suggested in Roe v. Wade that the states may enact stronger limits at the point at which abortion becomes more dangerous than childbirth.

Late-term abortions are more dangerous for several reasons. With late-term abortions, there is increased risk of infection and hemorrhage, embolism, perforation or rupture of uterus, and complications from anesthesia. The life and health of women is threatened by miscalculating the gestational age in late-term abortions.

There are also the long-term risks that are aggravated by late-term abortions, including the risk of pre-term birth (PTB) in future pregnancies. A full-term pregnancy provides a measure of protection against breast cancer. A late-term abortion increases the risk of breast cancer, as a 1997 study by Mads Melbye in the New England Journal of Medicine found (“With each one-week increase in the gestational age of the fetus, however, there was a 3 percent increase in the risk of breast cancer.”)

Who knows when “viability” occurs? Women don’t feel viability, as they do fetal movement (quickening). Only doctors looking at gestational age data and technical estimates of fetal survival at various weeks of gestation can estimate when “viability” occurs. A bright line, 20-week limit against late-term abortion is necessary to protect maternal health.

A 20-week limit is consistently supported by polling data, which isn’t a moral standard but a good guide for politicians. A majority of Americans think that second-trimester abortions (after 12 weeks) should be illegal. Even a Huffington Post poll found majority support for a five-month limit to abortions. Twenty-one states have passed five-month limits for several reasons. Based on the controlling decisions of the Supreme Court, it is important for state limits to be carefully focused on protecting both the unborn child and maternal health. Based on all available evidence, it is the earliest prohibition that will likely make it past the current Supreme Court.

Finally, it’s imperative that the Senate add maternal health findings to the five-month limit it is now considering. The bill would be greatly strengthened by adding these well-documented risks to maternal health. It would serve public education and considerably help the defense of the law in the courts. It makes no sense whatsoever for senators to make the public argument for a five-month limit on abortion with one arm tied behind their back, given the intense hostility of abortion advocates and of the courts. Congress should add the maternal health data and pass the Pain-Capable Unborn Child Protection Act.

Originally published in Townhall, on January 29, 2018.