By Naomi Schaefer Riley

First comes pregnancy — but then, thankfully, comes marriage.

On Monday, “Today” show co-host Savannah Guthrie announced that she married her fiancé Mike Feldman in a small ceremony last weekend. But that’s not all. The 42-year-old is also four months pregnant.

“We set the wedding date, I bought my dress, and then I found out,” she told viewers. “So I did a little praying. . . . I feel great, and actually I’m so happy to tell the world because I can’t suck in this gut anymore.”

To which one can only say: Mazel tov!

While it seems that the couple planned the wedding before the bun in the oven, it’s nice to see that they decided to go through with it anyway. Plenty of pregnant women these days decide to have the kid first and put off the wedding for a while, or indefinitely.

One can only hope that Guthrie is the leading indicator of a trend: the return of the shotgun wedding.

Getting pregnant before getting married used to be fairly common, according to marriage historian Stephanie Coontz. Coontz, co-chair of the Council on Contemporary Families, says that at the time of the American Revolution between 30% and 40% of brides were with child when they tied the knot.

That number dropped significantly in the 19th century, as ideas about female sexuality changed. As Coontz explains, things went from female passion as an almost uncontrollable force to the idea that “a good woman never even thought about sex.” Premarital sex (and pregnancy) began to become more common again in the 1920s, and by the 1950s as many as 25,000 babies born out of wedlock were being given up for adoption each year. With the sexual revolution, the advent of the birth-control pill and the ready availability of abortion, all that changed.

Today, of course, the stigma against childbearing outside of marriage is almost nonexistent.

Almost 40% of births in the US are to unwed mothers, even though all available research shows that children growing up with two parents married to each other are almost uniformly better off. According to Pew’s Economic Mobility Project, for instance, children from families where two parents have remained married are also more likely to rise up the income ladder if they grew up poor, and less likely to fall into poverty if they grew up wealthy. Researchers at the University of Virginia found that the child of a single mother is two to three times more likely to drop out of high school and boys raised by single mothers are more than twice as likely to be arrested before they are 30.

Unfortunately, it now seems that even if two people having a child want to get married, they are just as likely to put it off until after the baby is born or a few more years after that. According to a report last year called “Knot Yet: The Benefits and Costs of Delayed Marriage,” “most Americans without college degrees now have their first child before they marry.”

Witness the brides on “Say Yes to the Dress” who go on the show during their first trimester to be fitted for a dress they’ll wear sometime after the baby is born. It’s better now to walk down the aisle with a baby than a baby bump. Don’t these women realize that even if they get their figures back it will be years before the bags under their eyes go away? Maybe it would be better to have that “glow” of pregnancy instead.

A few of Hollywood’s leading ladies have come to this conclusion. Jennifer Garner, Drew Barrymore, Kate Winslet, Amanda Peet, Alicia Keys — they all decided to get hitched while pregnant. A Huffington Post article on these women said they had “more than one reason to be blushing.” Of all the things celebrity women could be blushing about, wearing a maternity dress to walk down the aisle isn’t high on the list.

It’s rare these days to wait to have sex til after marriage but at least these ladies realize the importance of having children inside a committed relationship.

Indeed, I think most of us would be perfectly happy to drop the pretense of the white wedding dress if more women would be willing to marry the father of their children sometime before the children are born.

Historically speaking, plenty of shotgun marriages worked out well, says Charlotte Hays, author of “When Did White Trash Become the New Normal?”

If you grew up in a small town in the 1950s or 1960s, “you probably heard whispers that parents of several of your friends who ‘had to’ get married because your little friend was on the way.”

I’m not suggesting we return to a time when men were actually forced at the end of a real gun to marry the girl they knocked up.

Still, as Hays notes, “the shotgun wedding made sure that a child had two parents at the time of birth and paid tribute to the notion of the family as an institution.”

So here’s to Savannah. You can breathe out now.

Naomi Schaefer Riley is the author of “’Til Faith Do Us Part: How Interfaith Marriage is Transforming America” (Oxford).